Tamron 17-28 F2.8 for Underwater Photography Review

The Tamron 17-28mm F/2.8 Di III RXD is without doubt one of the best options for wide angle underwater photography.

As I wrote in a previous article this lens has several strengths

1. Close minimum focus distance (19 cm wide – 26 cm tele)
2. Lens does not extend when zooming
3. Reasonably compact (99 mm and 420 grams)
4. Good sharpness at the edges from f/4 onwards
5. Low cost compared to other Sony lenses.

The lens will cost you $799 vs $2,299 of the Sony 16-35 GMII which is the best lens in this class however the price difference will convince most people especially those only using the lens underwater that the Tamron is the way to go.

Parts for Nauticam Housings

The Nauticam 18809 wide angle dome port is not a classic dome but has design without a flat base. The port has 11cm radius of curvature and is 85mm deep 180mm wide this means the entrance pupil needs to be 25mm behind the extension.

Nauticam 18809 180mm Wide angle dome port

Nauticam recommended extension is 40mm when combined with the 35.5mm N120 to N120 port adapter. Due to the shape of the lens this cannot be used with the N100 port as the zoom is close to the front of the lens.

Tamron 17-28mm with Nauticam zoom gear

Underwater housing manufactures unfortunately do not apply any science to the selection of domes and extension for a lens but out of pure coincidence the 40mm extension ring is what this lens requires.

Tamron 17-28mm 35.5 adapter and 40mm extension

With the 40mm extension the glass port will be exactly 11 cm from the entrance pupil and focus right on the surface.

The Nauticam parts will set you at $2,284 for the gear, extension and wide angle port.

Pool Session

I had already shot the Tamron in the murky waters of my local pool so I went to Luton that has a better filtration system and started with my usual shots.

I took shots from f/2.8 to f/22 obviously f/2.8 and f/4 are purely academic but decent results are obtained from f/5.6.

Tamron 17 2.8 Close

At F/2.8 most of the area outside centre is blurred.

Tamron 17 4.0 Close

By f/4 we have a substantial improvement.

Tamron 17 5.6 Close

At f/5.6 the lens is better than most already considering the very close shooting distance. Unfortunately at this stage I picked up a bit of debris on the dome and did not realise…

Tamron 17 8.0 Close

f/8 is very good and this is your default for shots that are not close when edges are not important.

Tamron 17 11 Close

f/11 is probably the best overall compromise between edges and centre.

Tamron 17 16 Close

By f/16 depth of field keeps everything in focus however the lens has dropped in the centre.

Tamon 17 22 Close

f/22 gives you a consistent frame but with evident resolution loss.

All the shots above have distortion correction deactivated.

I then went and shoot a tile wall to see how straight is the lens here lens correction is applied.

Tamron 17 5.6 Wall

At f/5.6 shooting from 1.8 meters performance is excellent.

Tamron 17 8.0 Wall

f/8 is even better across the frame and is your default if depth if field is not essential.

Tamron 18 11 Wall

f/11 is great

Tamron 17 16 Wall

f/16 and f/22 give consistent sharpness as expected again those apertures are normally not necessary.

Tamron 17 22 Wall

Shooting people with the Tamron

One of the things you do with a rectilinear lens is to shoot straight lines and correct proportion people and wreck interiors for example. The inside of the pool lends itself well to this.

Tamron 17 2 divers 8

With subject not close the lens has a great pop and rendering at f/8

Tamron 17 side 8

Even closer subject with not far background look great.

Tamron 17 diver 8

If you need the background to be sharper you can stop down.

Ascent 11

Again considering that even WWL-1 and WACPs really need f/11 this looks terrific.

Knee down 14

A final example shows that f/14 is enough to give you the depth of field you need when the subject is not too close.

Conclusion

There is no doubt that if you are in the market for a rectilinear wide angle and you are budget conscious this is the lens to get full stop!

Methods to determine the appropriate dome port for a wide angle lens in an underwater housing

Warning this is an extremely technical article that I have written on request. If you are not familiar with optics, geometry, housings do not attempt to perform a calculation by yourself and rely on expert advice.

Background

The physics of dome ports are not new to underwater practitioners although not many people understand the formulas, it is well accepted that there is a correct way to size and position a dome port in order to optimise optical performance of a lens inside an underwater housing. I do not want to repeat the theory here but if you feel you need a refresher the excellent articles from the now passed David Knight and specifically the piece on dome port theory will be useful. For the purpose of this article I will consider only underwater imaging, split shots and over and under have different considerations and will be addressed separately in due course.

Practical Implications

For our purposes, what is interesting is that a dome port is able to restore the lens air field of view when the camera and lens are inside a housing. The theory says that this happens when the centre of the dome lies on the lens entrance pupil. But what happens if it does not?

Jeremy Somerville has created a number of visualisers that although not totally correct give a good idea of the issues  involved. In particular the positioning of the dome port is something you may want to check. In short if the dome is not correctly positioned we lose field of view as result of distortion and increase the amount of chromatic aberrations. 

We also have to consider that the dome port being a single element lens has also issues of field of curvature and spherical aberrations which are additional to any considerations on positioning and require the user to stop down the lens to reduce the side effect. Those side effects are exacerbated when the dome is not correctly positioned to the point they cannot be corrected no matter how much you stop down the lens.

Choosing appropriate wide angle lenses

Minimum Focus Distance

One of the key takeaways of dome port theory is that if your lens is not able to focus close it may not work at all inside a dome, which in turn means your dome starts to become bigger and bigger to allow your lens to focus or you need to introduce close up lenses which further deteriorate optical quality.

More compact set ups and smaller domes require lenses that can focus close. In addition, due to the dome port optics, infinity focus will be reached at 3x the dome radius from the dome surface: your lens will work to a maximum focus distance well under one metre and closer to half a metre. This is a challenge for wide angle lenses that are designed for landscape and not usually optimised for close focus. One assumption that you cannot make is that a lens that is great for topside use will perform equally well behind a dome, or even more interesting a lens that is small and compact may require a quite sizable dome to work properly underwater which negates the size benefit to start with.

The dead Zone

The dead zone is where the camera cannot focus because our subject is too close. Our objective is to place the dead zone inside not outside our dome so that we can maximise the range we can use for imaging. It is not an issue if the dome radius is so big that the focus area falls well inside the dome, in fact it may be an advantage, but if the camera focus distance is outside the dome we are eating away useful range and at the point where the focus distance is so far that is outside the dome infinity point the camera will not focus at all.

By choosing a lens that can focus very close we accomplish two objectives:

1. We reduce the size of the dome required
2. We maximise the focus range that can be used.

I prefer lenses that have a minimum working distance around 20cm, and avoid anything that focuses from 25cm and beyond, this ensures good image quality and reasonably compact set ups.

Prime vs Zoom

Prime lenses have a fixed entrance pupil this means that once the dome is sized and positioned your job is done. Zoom lenses instead change in size or move the entrance pupil to accommodate changes in the field of view. This is bothersome as it means that if you determine your dome parameters at wide end this may not be correct at tele end. In addition as the angle of view is being reduced the curved surface of the dome will start looking more and more flat. This is a challenge but not one we need to address, as seen in the flat port theory lenses that are longer than 35mm suffer less from chromatic aberrations, therefore for our purposes we will treat zoom lenses like a prime lens whose focal length is the shortest our zoom can manage, i.e. the wide end of the zoom. At the tele end the dome with a zoom lens will look like a flat port but still have some benefit over it in terms of aberrations.

Zoom factor

Although we said we will consider the zoom lens as a wide tele, lenses with a zoom ratio much bigger than 2x will most definitely be problematic. This is the reason why zoom lenses with conservative ratios like a classic 16-35mm are bound to perform overall better  than say a 20-70mm lens. Lenses in the classic 24-70mm or 28-75mm range tend to have less problems because they are not that wide to start with and generally work well as long as they focus close, otherwise they will require larger domes. 

Example Cases

I have good experience after one year on e-mount and therefore I am going to list a few examples of lenses that are excellent topside quality but are bound to work not so well underwater as well as other lenses that have good potential at different price points.

Lenses requiring large domes for optimal performance

Sony 12-24mm F.2.8 GM – a high quality super wide zoom lens that is great for topside use. It has a minimum working distance of 28cm and is 13.7cm long. This lens will likely require a dome port with a radius in excess of 14.3 cm and a field of view of 122 degrees. A port like this is not standard on the market.

Sony 20-70mm F4 G – a versatile topside zoom with extensive zoom. It has a minimum working distance of 30 cm and is only 9.9 cm long this lens is likely to require a dome port over 20 cm in radius to perform at its best.

High Potential Lenses

Tamron 17-28mm F2.8 – A lens that is cost effective and sharp with a limited zoom range. It can focus as close as 19cm and with a size of 9.9cm will require a dome of just over 9cm to have the focus range inside the dome. 

Sony 16-35mm F2.8 GM2 – An excellent topside lens that has a good zoom range and can focus at 22cm. With a physical size reaching 12cm this lens is likely to work with domes that are not excessively large.

Sony 20mm F1.8 G – An amazing low light lens that can focus at 19 cm. With a physical size of 9cm this lens is likely to work with relatively small domes and produce outstanding image quality.

Comparison at equal field of view and different working distance.

The graphic above illustrates how two lenses with equal field of view displayed in solid green require different dome radii depending on the minimum operating distance. The small inverse triangle is the area inside the lens up to the focal plane.

Lens1 will require the smaller dome so that the area not in focus falls inside the dome, if a larger dome is used this simply expands the focus range into the water proportionally to the increased dome radius. A lens with the same field of view but longer MOD2 will require a larger dome to ensure the area out of focus is inside the dome. A smaller dome can be used however the dead non focus area now moves into the water. As the infinity point is still set at 3x the dome radius from the surface using this smaller dome means less focus range can be used by the camera. Using too small domes deteriorates image quality because the compressed focus range has an impact on the overall image resolution.

Locating the Lens Entrance Pupil

In order to properly position the dome port we need to determine where the entrance pupil of our lens is. There are at least 4 methods that can be used to locate the entrance pupil of the lens.

Method 1 Look into the lens

It makes me smile when you read: locating the entrance pupil is easy just look into the lens and see where the aperture is. I do not find this easy at all, first lenses are increasingly complex in construction and second how do you place depth of the aperture correctly even if you can see it? The error margin of this method is very high.

Method 2 Non Parallax Point

If you are into panorama photography you know that you can locate the non parallax point which is the lens entrance pupil using a slide mount and a specific set of targets. 

A demonstration of this method is beyond this write up however if you want to go deeper into this this article should help you. This method has a good level of precision and panotools maintains an entrance pupil database for many DSLR lenses.

Method 3 Trigonometry

Once you know the lens field of view you can use various filter rings to determine the thickness where vignetting occurs. At that point you can simply calculate the distance from the edge of the entrance pupil by taking the ratio between the lens radius and the tangent of the angle of view. This gives good precision and does not require anything else than the lens itself and a few filters but can be approximated also for a lens you do  not own using standard roundings.

Method 4 Lens Design

There are some websites that have lens design drawings directly from patents. This will give you the exact location of the entrance pupil from the image plane and from the lens mount.

I use the site maintained by Bill Claff called the Optical Bench Hub. Unfortunately the database is not complete, some specific brands designs are scarce. The benefit of this method is that you can use it to make calculations before you buy the lens and it is 100% accurate.

Entrance Pupil Determination – Practical Examples

Case 1: Lens Design Available

Sony 20-70mm F4 G lens is a very versatile zoom, whe wide angle 20mm is sufficient for many situations and the tele end of 70mm good for close up work on land. This lens makes a good candidate for underwater use in terms of angle of view however it has a minimum operating distance of 30 cm which is far from ideal.

We locate the lens design on the Optical Bench Hub here.

The important parameters are I distance from the edge of the lens to the image plane (sensor) which is 115.04mm and P distance of the entrance pupil from the lens front.

The difference I – P = 91.79mm still accounts from the flange distance. Taking that out we get 73.79mm from the lens mount.

The lens has a minimum working distance of 300mm. If we subtract the entrance pupil distance from the image plane of 91.79mm we determine a minimum dome radius of 208.21mm which is rather large and in fact not available if not as a custom product.

Of course we can still go ahead and use a smaller dome radius however all the range between the MOD and the edge of the dome will be wasted and not produce an image in focus.

Sony 20mm F1.8 G lens is the modern equivalent of a Nikkor UW15 giving a field of view that is acceptable for most uses and excellent image quality.

We locate the patent on Optical Lens Hub here.

The lens has a MOD of just 19cm the distance I-P=80.91 a dome with a radius of 11cm will contain the entire non focus area. The entrance pupil is 62.91mm from the lens mount.

Case 2: Lens Design Not Available

The Tamron 17-28mm F2.8 is an affordable, fast and high quality wide angle lens with a somewhat limited zoom range. The lens is 99mm long and takes a 67mm filter thread. I used an ND1000 Hoya Pro filter with a thickness of 5.6mm, the lens external radius is 69mm with the filter on.

The lens nominal field of view is 103.70 degrees however all mirrorless lenses have software corrections. Ideally I need to know the real field of view however the error is normally 1 to 3% and does not influence the calculations too much.

If we consider a length of the lens and filter of 104.6mm and a radius of 34.5 mm for an angle of 51.85 degrees we obtain a distance from the lens mount of 77.5 mm and from the focal plane of 95.5 mm. Taking into account that the MOD is 190mm this gives a minimum radius of 94.5 mm for the dome which is very good news.

Sony has recently released the 16-35mm F2.8 GM2 with a MOD of just 22 cm. Using the same logic as before we calculate the entrance pupil to be 93.5 mm from the lens mount or 111.5 mm from the sensor. This means a dome radius of minimum 220-111.5=108.5 mm is required to contain the area not in focus inside the dome.

Dome Selection Part I – Field of View

The first thing that  we need to ensure is that the dome field of view can contain the lens field of view otherwise our main objective of preserving the air performance would be lost.

Unfortunately the specifications of dome ports on the market are somewhat lacking so you need to make do with what you have or ask for CAD details.

I use Nauticam that do produce good documentation, zen does this too 18809 18810 18812 18813 18815 N120 Optical Glass wide angle port.pdf

Here you can see that, ignoring the thickness of the glass for simplification purposes the various ports have the following field of view using the formula 2*arcsin(glass port diameter/curvature radius)

Part Number	Description	Angle of View (degrees)	Widest Lens mm(Full Frame Eq)
18809	180mm Optical Glass Wide Angle Port	109.8	16
18812	230mm Optical Glass Wide Angle Port II	146.8	7
18813/18815	250mm Optical Glass Wide Angle Port II	102.75	18

It is somewhat surprising to see that the larger port  in terms of size is the narrower in terms of field of view I believe this is a compromise in terms of weight.

Dome Selection Part II – Curvature Radius

Looking at field of view is not sufficient, we also want to ensure that the lens MOD is contained by the dome and therefore we need to take into account the actual radius of curvature of the port

• 18809 180mm Optical Glass Wide Angle Port Radius 110mm
• 18812 230mm Optical Glass Wide Angle Port II Radius 120mm
• 18813/18815 250mm Optical Glass Wide angle port Radius 160mm

The port size goes with the curvature radius however somewhat surprisingly the difference between the 230mm and 180mm port is rather small making the choice between the two more a matter of field of view.

Amount of Recession of the Camera from the Port

Camera housings are not like skin, armed with a digital calliper you need to determine the distance between the lens mount and the housing port mount. Alternatively you can reverse engineer this once you have a lens port combination that is absolutely exact.

For the purpose of my calculations I have measured that my E-Mount camera is 27mm recessed inside the housing. This is important as it is needed to calculate the extension for the dome. If you are in a different format you need to measure this distance yourself.

Entrance Pupil to Housing Port

We have previously determined the entrance pupil from the lens mount and now we know how much this is recessed in the housing so we can calculate the required extension to reach the entrance pupil however this assumes the domes are hemispheres which in most cases they are not. Let’s leave this aside for one second and go back to our examples.

Sony 20-70mm F4 Entrance Pupil Distance = 73.79mm – Housing recession 27mm = 46.79mm from the housing

Sony 20mm F1.8 Entrance Pupil Distance = 62.91mmm – Housing recession 27mm = 35.91from the housing.

Tamron 17-28mm F2.8 → 50.5mm from the housing

Sony 16-35 F2.8 GM2 → 66.5mm from the housing

Wide Angle Ports

Again we need a calliper to determine the depth of the port as those are not full hemispheres. I have access to the 180mm dome and I know that the port is actually 8.5cm tall from mount to glass edge because I measured it. This means I need to add 25mm to the extension required. From the manual I estimate the 230mm port needs extra 13mm and the 250mm port 34mm. if you own those ports and want to provide me the exact measurement I will build a calculator for dummies.

Back to our examples with some real calculations:

Sony 20-70mm F4 Port required 250mm Wide angle Port. Extension required 46.79+34mm=80mm

Sony 20mm F1.8 Port Required 180mm Wide angle port. Extension required 35.9mm+25mm=60.9mm

Tamron 17-28mm F2.8 Port Required 180mm Wide angle port. Extension required 50.5mm+25mm=75.5mm

Sony 16-35 F2.8 GM2 Port Required 180mm Wide angle port. Extension required 66.5mm+25mm=91.5mm

If we are using the 35.5mm N100 to N120 adapter this means that the actual extension rings required are 

Sony 20-70mm F4 → 80-35.5=45 mm Part required N120 Extension Ring 45

Sony 20mm F1.8 → 60.9-35.5=25.4 mm Part Required N120 Extension Ring 25

Tamron 17-28mm F2.8 → 75.5-35.5=40 mm Part Required N120 Extension Ring 40

Sony 16-35mm F2.8 GM2 → 91.5-35.5=55 mm Part Required N120 Extension Ring 55

Nauticam Port Chart Check

Lens	Extension Determined	Extension Suggested	Delta
Sony 20-70mm	45 mm	40 mm	5 mm
Sony 20mm	25	NA	NA
Tamron 17-28	40 mm	40 mm	0 mm
Sony 16-35GM2	55 mm	50 mm	5 mm

We can see that for the 20-70mm where the entrance pupil is known the Nauticam port chart is off 5mm. For the 17-28mm where design information is not known there is no discrepancy with my method and for the 16-35 GM2 there is a discrepancy of 5mm.

I checked the situation for the 16-35mm GM2. This lens has some distortion and therefore the uncorrected field of view is 109 degrees which is too big for the 180mm wide angle port. With my calculated 55mm if you remove distortion correction in camera you can see a tiny bit of shading from the dome petals but this goes away when distortion correction is active. Therefore I am satisfied that my calculations are more accurate. I contacted Nauticam who ran the MFT charts in their test rig and they said 55mm works well too. Although it is ideal to have the exact extension if you have one that is 5mm off the calculated value and the dome does not vignette you need to consider if the image quality you get is satisfactory and make your call.

I also tested this lens in a pool, you can read the review in this post.

What about other brands?

The challenge with other brands is the lack of documentation however you can contact the design department to obtain information on the dome port they should not be a secret. The other challenge is the availability of extension rings. The Nauticam system has a level of precision of 5mm which is excellent however I am under the definite impression that they run their tests using in most cases steps of 10mm and using as first approach how the lens fits the port, they do not go and attempt to determine the entrance pupil.You can observe that because when you look at a specific port say the 180mm wide angle and you apply the suggested extensions in all cases the lens edge is flush with the extension.

In most cases this turns out to be accurate however there are some cases where wider lenses need to be more recessed and narrower lenses need to stick out more.

Fisheye Lenses

When you use a fisheye lens with a complete hemisphere dome port the calculations remain the same however it is a bit simpler to proceed without data. If your fisheye has a diagonal 180 degrees view and your extension is too long you will see vignette in the corners. However if you push your fisheye lens closer to the glass you may be able to use a dome with a smaller field of view but the edge distortion will increase and so will chromatic aberrations. A classic example is the 230mm wide angle port used with a fisheye lens. The port has a field of view of 146.8 degrees which is far away from the required 174 degrees of a diagonal fisheye lens. 

Panotools provide entrance pupil for the Nikkor 8-15mm therefore we don’t need to go trial and error. The Canon 8-15mm Fisheye is on the Optical Bench Hub.

Following the same logic we determine that the entrance pupil is 129.98-18-17.98-27=67mm from the housing. Taking out 35.5mm for the adapter we get 31.5mm vs the 30mm on the Nauticam port chart. This means the lens will stick out from the dome opening and that is fine as a shorter lens would make it vignette. Try it if you have a 35mm extension you will see the vignette. If you have access to all extensions in steps of 5mm you can determine the correct one when the vignetting stops even without the entrance pupil position. Please note the above calculation is to use a Canon EF lens (flange distance 44mm) on E-Mount (flange distance 18mm) however if you work that out in the N120 Canon system with the additional gap for the more recessed housing you end up in exactly the same place.

Wrap Up

This article has shown that it is possible, with basic knowledge of trigonometry and access to lens, dome and camera design information to determine:

• How well a lens may work
• What is the minimum dome radius required to preserve the image quality
• What is the extension required
• How to find out the required field of view of your port

Without acquiring the actual lens camera or wide angle port. It is important to understand that if a lens is weak in air it won’t get better in water and in particular you need to appreciate that topside tests are not identical to use behind a dome that instead means working at very close focus well under one metre mostly around 30 to 50 cm. It may be worth it in some cases to rent a lens if available and take some tripod shots at close range. If you see really weak performance the lens may not be worth housing it at all.

One of the misconceptions that has propagated in the last few years is that all rectilinear lenses offer poor performance compared to water contact optics and you need to stop down to very small apertures to have good edges. From my personal experience with the Tamron 17-28mm, I can conclude that this lens is far sharper than the water contact optics that require a similar investment and even beats more expensive options (WACP-C) however the rectilinear look is somewhat not in trend in underwater photography. Majority of photos want the centre to pop and this works better using fisheye lenses or distorted optics at close range. Still there is a place for rectilinear lenses: models, wrecks where shapes are known, even fish and marine life where the exact dimensions matter for scientific purposes.

I hope that this article allows you to have a more informed view of the key factors to look for in a lens that will ensure underwater performance is as good as it can be.

Sony FE 16-35mm F2.8 GM II for Underwater Photography

The latest addition to the GM family from Sony has been the mark II of the 16-35mm wide zoom lens.

Nauticam has recently released the zoom gear for this lens and has it on the port chart with a 50mm extension for the 180 wide angle port and 60mm for th 230 wide angle port the SKU is 37175.

I have owned this lens since September and has become a favourite for topside landscape trips. It produces very sharp images across the frame with excellent rendition.

The lens is quite big and takes 82mm filters. An interesting characteristic for underwater use is that the lens is longest at wide and and shortest at tele end. It has also a minimum operating distance of 22cm and is 12 cm long leading to small dome port requirements.

My preliminary tests indicate that this lens will perform best with a 55mm extension ring and after aquiring the zoom gear from Underwater Visions I made my way to Luton Inspire last night.

During my hour in the water I was called to take photos of a scuba dive experience nonethless I managed to run a series of test.

The lens is sharpest at f/5.6 and it drops afterwards a trend of all Sony mirrorless. I took tests shots at f/5.6 f/8 f/11 f/16.

The initial test is the demanding MOD test get as close as possible to a target and shoot a wide scene.

F5.6 MOD

F8 MOD

F11 MOD

F16 MOD

In terms of centre performance best results are at f/5.6 decreasing as you stop down.

I then take the same shot putting the target at the bottom edge.

F5.6 MOD Edges

F8 MOD Edges

F11 MOD Edges

F16 MOD Edges

The situation changes with best edges at f/16 however good results are already found at f/11

The wall test gives similar outcomes this is taken at around 1.5 meters.

F5.6 Wall

F8 Wall

F11 Wall

F16 Wall

With a target that is not near f/8 and f/11 do best suggesting those aperture are those to use for general cases, this is a good result.

Time to show some example shots.

F8 Example

F11 Example

There is no doubt that the lens is very sharp across the frame. You can zoom into the full rez images to see the detail.

Comparison with Tamron 17-28mm

So far the Tamron 17-28 held the prime spot for the best rectilinear lens on the Sony full frame format. I would say that the Sony 16-35mm GM2 is on par with maybe an edge on the overall resolution at f/11.

Consider though that the Sony is almost 3x the price is it a worthy upgrade to the Tamron? My view is that it is not.

If you bought the lens to take it underwater the Tamron is identical you cannot tell them apart, however if you own or like the 16-35GM2 as topside zoom the focal range is much more useful.

Conclusion

Strong performance from Sony and definitely recommended with the 180 wide angle port. I do not own the 230 port that has 1 cm wider radius but would expect marginally better performance.

Open Water: Canon 8-15mm with Kenko 1.4 Teleconverter

In a previous post I described the use of the Canon 8-15mm as a zoom fisheye using the Kenko Teleplus HDpro teleconverted.

I had the opportunity to try this set up in Malpelo although in a situation that was not ideal for it.

I put this lens on expecting some wide angle school shots and instead it ended up being a dive with Galapagos sharks coming fairly close.

With the imminent launch of the Nauticam Fisheye Conversion Port many users will ask if they shoud invest in that or they can get decent quality at more affordable cost spending less then £800 for a teleconverter set up. I assume any Sony full frame E-mount shooters own both the Canon 8-15mm and the Sony 28-60mm.

Edit 9 March 2024

Studio Shots

I found some time to do some tests at f/16 distance 25cm which is typical of wide angle in a dome.

As you can see the kenko 1.4 TC does not loose any quality compared to the bare lens and looks more magnified at same focal lenght in the centre.

Canon 8-15 15mm f/16

Canon 8-15 1.4 15mm f16

Why is the quality the same? Probably the Canon 8-15mm is a better lens at 10.7mm that it is at 15mm and therefore even with the teleconverters result match. This corroborates my in water results.

Malpelo Shots Analysis

The dive was early in the morning and topside overcast resulting in a fairly dark dive.

The sharks came fairly close however as soon as the strobe fired they turned on their back. My impression was that this was more due to the noise of the strobe firing then the actual light.

All my shark shots are at f/8 1/30 ISO 500. As the shutter speed is quite low you have situations where the subject is sharp but some of the fish at the edges has some motion blur this is unrelated to the lens.

Profile

If you open the above image on a separate tab and zoom 100% you will see that the shark is pin sharp and so are the small fish on the same focal plane and the one behind. The reef on the left bottom corner is soft.

This has to be expected as the focal point is further back from the shark so the camera is out of depth of field on that corner.

The situation repeats in other shots like this one where the shark is even closer however the edge improves due to the reduced distance gap with the reef.

Checking in

Turn back

Again shot after shot the fact I was focussing on the shark that was deeper in the frame resulted in the left edge being soft, this has to be expected and there is nothing wrong with the set up the dome or else.

I took some shots really close on the reef at f/16 to make the point here the muray eel is sticking out of the reef so the edges look much better.

This other shot has an hawkfish in the edge you can still see the coloration and the eyeball of the fish.

Conclusion

In general terms shooting f/8 on full frame is not an example of small aperture in fact this is a setting for distant subjects almost and wide angle scenes. In the environmental situation I was in I could have increased the ISO to achive higher shutter speed and smaller aperture however this would have resulted in more noise and loss of resolution across the whole frame. My view is that for general wide angle where there is no clear subject you can try to focus closer to have the edges sharper however this is not always a possibility with sharks and things moving and furthermore there is rarely anything of interest in the edges.

This was my second time with this combination and I remain of the opinion that the teleconverter does not take anything away in the center of the frame and deteriorates the edges only just slightly and is therefore a worth addition. The nauticam FCP is not yet released and combined with the 28-60mm will for sure produce a more flexible set up because of the increased zoom range compared to the teleconverter however if this produces better image quality on the overlapping range remains to be seen. I expect it will cost considerably more than the £800 required to add the teleconverter to your Canon 8-15mm.

Diving Malpelo Sanctuary of Flora and Fauna

It is a long time I do not write post that are a real blog but the trip to Malpelo deserved it.

I decided to take two cameras with me so that I could shoot topside without the pressure of taking the camera outside the housing.

Things to know about Malpelo

Malpelo island is a small rocky island off the coast of Colombia and is not inhabited if we exclude the thousands of birds that live on it and the few soldiers that manage the outpost.

It is situated around 500 km away from mainland and is 1.5 km long for 640 meters wide at the best. The island is volcanic in nature and despite being a Sanctuary of Flora and Fauna has no vegetation on it.

During our stay we had several thunderstorm that resulted in small waterfall from the cracks on the rocks.

There is no mobile phone coverage as you sail off the coast and the only way to get signal is to use a satellite phone.

Malpelo has two weather seasons and dive conditions change considerably:

• January to April – Dry season
• May to December – Wet season

The main difference in addition to the fact that it rains is the water temperature and the depth of the thermocline.

Most people go to Malpelo to see hammerheads and as the weather gets warmer the thermocline goes deeper and so do the hammerheads.

On the other hand visibility improves during the wet season so if you are into video or photo you can get 20+ meters visibility compared to 10-15 in the dry season.

I went in June and this meant schooling hammerheads in the blue and thermocline at depth. I knew about it but other guests didn’t so they were either disappointed or pushing the dive guide out into the blue to see them which frankly was not ideal.

There are only two boats that visit Malpelo regularly the MV Ferox which is what I used and the Sea Wolf. The Ferox caters to more international travellers is entirely made of steel being a former Swedish minesweeper. The Sea Wolf hull is made of aluminum it is more comfortable in terms of living area but suffers the sea conditions much more. The clientele is more local or South American. The two boats have a set number of permits and at one time there is only one boat except on arrival and departure day when you may cross the other one.

The trip starts from the Intercontinental hotel in Cali and you get to Buenaventura after a 3+ hours coach ride in extremely bendy roads with many tunnels. You embark the MV Ferox ribs directly from the touristic port of Buenaventura. Due to the level of crime in this location you stay there the absolute minimum amount of time. The destination was not flagged as safe by my travel insurance as of June 2023.

I shot a little clip of the process of getting on the boat that should give a good idea.

Getting Aboard the MV Ferox

As you can see from the clip the boat is not exactly luxurious. I was in a full size cabin so I could set up my camera inside. All other cabins except the doubles were smaller. There is no dive deck as you dive from the RIBs and the upper deck was absolutely super slippery the moment you had some rain.

Transit to Malpelo

The Ferox leaves after dinner on day 1 and then travels non stop until arrival. Conditions were pretty calm during my crossing and the boat arrived in Malpelo at night.

MV Ferox Transit to Malpelo Sanctuary of Flora and Fauna

Once arrived the boat stayed on a mooring point on the north east of the island in front of la cara del fantasma dive site and close to the military outpost.

If you are prone to sea sickness please note that the boat is only attached to a single mooring point and therefore will move with the wind and the waves. In addition the generator providing light is quite noisy and goes on non stop. My earplugs were not good enough for a quiet night, I recommend you invest in heavy duty ones for shooting.

Dive Operation

The dive operation is absolutely superb in terms of logistics and organisation.

The two RIBS travel on the deck of the boat during the crossing and are dropped in using cranes upon arrival. The scuba gear that was set up during the crossing is loaded on the RIB by the crew and stays there for the duration of the trip until unloaded and then the RIB are lifted back on board.

Tanks are filled directly on the RIB, this set up is fantastic as you only have to make it to the boat while your camera gets passed to you. Due to the surface conditions anything different is not advised.

MV Ferox Dive Operation Set up

The Diving

I was expecting absolutely barren rocks with no coral after reading several sources however this proved to be wrong. There are hard and soft corals, not as you would expect in Egypt, but plenty to have macro life which of course was not the main objective of anyone on the trip.

Soft Coral Pinnacle

Sway

Wrapped around finger

Wrasse

Butterflies

Fish Schools

One of the most attractive features of Malpelo in the wet season are the huge aggregations of fish. When I say huge I mean that the lens I brought for that which is what I use in Egypt for the local school was simply not wide enough.

D’Artagnan Dive Site – Sanctuary of Flora and Fauna of Malpelo Island

The three mosqueteros, pinnacles to the north of the island were the best for schools.

Snappers at D’Artagnan I

Snappers at D’Artagnan II

Snappers at D’Artagnan III

For the great joy of photographers and videographers.

Selfie-sh

Breaking the school

The school of trevallies there is no doubt the biggest school I have ever seen to date and lends itself to all sorts of wall to wall shots.

Upside

Arrows down

Couple

Red Mullets

My absolute favourite were the snappers though due to the coloration.

In a dive site I even saw two schools of different species in a sort of alliance.

Two Schools

The Giant Moray – Queen of Malpelo

Although people go to Malpelo for sharks a special mention goes to the amount of (free swimming) giant morays. The population is huge and this fish is really a pleasure to watch and capture with your camera.

El Arrecife – the check dive

Moray on Red

Spongers

Howling

There are of course other reef fish and some of the least shy hawkfish I have ever seen.

Hard Coral

What about Sharks?

And here comes the elephant in the room. Did we see hammerheads? Yes however the largest school was circa 12 and far away in the blue.

Guides discourage using strobes or video lights when those point to the blue (why would you do that anyway?) but it is ok to beam the sharks with light when you shoot against the reef.

La Nevera is probably the best site for hammeheads due to the strategically placed cleaning stations.

La Nevera

However there are other sharks in Malpelo with warmer water.

Firstly Galapagos shars some specimen really large as well and they do come close.

Profile

Checking in

Turn back

Frontal approach

Get closer

Sharks tend to turn back as they hear your shutter or your strobes makes a ready sound hence the reason some of those look like turning back. I had a Canon 8-15mm with 1.4 TC for those shots so the shark are closer than they look.

Other subjects that are easier to capture are eagle rays saw up to six together. By no means a large aggregation but quite easy to track.

Eagle and Riccardo

Fly high

Whitetip down

White tip sharks were quite common as well.

We also saw tiger sharks which is one of the reason we did not see many silky sharks (they can eat them) on the same sites. Humpback whale were seen in the distance and a whale shark came under our rib after a dive at El Monstruo.

Whale shark at Baio del Monstruo

Crew

Special mention to the dive guides of the Ferox, I was with a spanish speaking group with Richi Valens who did an awesome job. The other guide Sten is also very well known and long time guide in Malpelo having worked with previous operator departing from Panama.

The whole boat crew were very helpful and the food was light for once: not the usual fatty foods that you experience on some other liveaboards. Beers were $2 per can but a whole bucket was served free after the last dive.

The skippers of the two RIBS are just incredible for the mix of agility, seamanship, strength pulling up BCD with one hand from the tank neck.

Conservation Efforts

While there we met Camilo Abella a park ranger with a degree un biology and excellent English more info on the efforts of the rangers here

A catamaran from Biodiversity Colombia patrols the island at all times to stop ilegal fishing oh sharks. They stay on the boats in 3 months shifts to keep things as they are.

I left a donation when I was there and I hope you will do the same after reading this blog.

Few Other Considerations

I guess many people will be thinking is Malpelo for me or not? And the answer does change a lot depending on your preferences and priorities.

If you need a luxury liveaboard and mind rough surface conditions Malpelo is generally not for you. I would also add that for photographers wanting to take pictures of hammerhead sharks there are places where this is considerably easier. Cocos Island where you can sit on the bottom waiting for sharks is definitely a safer option than Malpelo where contact with the bottom is broadly not allowed, unless with a few fingers if there is ripping current. Even Galapagos despite the reputation has considerably easier diving conditions. To understand how tough it is in Malpelo you need to look at the entry and exit on the tenders. In Galapagos you will still get in and out the tender with your gear in Malpelo that is very risky business. Many dive require short crossings from one pinnacle to another with strong currents and most people are forced to dive with 15 liters tank. If your air consumption is too bad and you are on 12 liters your are told you need to change by the guides to avoid cutting it short for the group. You are also asked to go higher and dive with the bubble of the group if you are running low but this is not a great idea.

In terms of safety you need a surface marker buoy, a flashlight; a beacon to find you in case you are lost is provided. I also carried a knife and a reel which I had to use in one occasion. During the trip I realised that smaller domes are really to be preferred I had a difference of 20 bars air consumption when switching from WWL-1 with its 5.5″ dome to a larger 180mm wide angle port. In addition I got strain on my left arm for carrying my 7 kg video rig in and out the rib and in and out the cabin depite getting help. Super heavy rigs are not ideal for the rollback negative entries required on each site. Going in and waiting for the skipper to pass the camera is not a good idea either as the group could have drifted.

Would I go back? Immediately and next time in the dry season.

Fine Tuning your Nauticam A1 Housing

What does my housing have that your does not?

I guess lookig at the title image you may spot two small differences.

Those parts are installed.

Required Parts

You will have noticed that your housing does not have a screw hole to mount a ball to put your monitor or focus light.

What you need to do is to remove one of those from the handle plates.

Allen bolt to be removed

You can then install the M5 ball so that you can use it to put the accessory you need.

M5 Ball installed

I am left eye dominant so I want to have free space in front of my right eye while my left is on the viewfinder so I put my ball on the left however you can do as you see fit.

You can also take the rubber assembly out of the socket and put an M10 ball mount which is more sturdy however you will be screwing metal on metal and I do not recommend that.

The other thing that you have noticed is that my housing has almost equal distance between the handle ball mounts and the centre.

Overview

However the housing as it comes out of the factory has a shorter distance between the left handle and the center than the right handle as consequence of the camera lens mount being on the left.

This is ok for topside but for underwater as soon as you are taking very close images with two strobes you will realise you have lights uneven and more shadow on your side.

Installing a single spacer into the handles give you this.

Spacer installed

Now your strobes or lights are simmetric however the housing fits a bit more snug into the travel case if you use that. You may need to remove it for travel if you pack case in case as I do.

Hopefully this was useful subscribe to my channels on for more tips and/or to this blog to get updates. And feel free to donate using the button on the left hand of the menu.

https://www.youtube.com/interceptor121

Sony 28mm Prime vs 28-60mm Zoom with the Nauticam WWL-1

The Sony A7R2 was released in 2015 some time later Nauticam released the WWL-1 and I was told this wet lens would work with a Sony full frame using a 28mm prime.

Years later I own a Sony A1 and I have been considering the 28/2 prime as a complement to the Sony 28-60mm mostly to address sharpness issues at the edges.

There is no doubt that the 28-60mm is a great little travel lens and perfect companion of the A7C however performance at the edges is never quite right no matter how much you close down.

Build Comparison

The 28mm prime is smaller than the 28-60mm when this one is extended but has a wider front element.

SEL2860 vs SEL28F20 Side

The side by side comparison shows that the 28mm is 9mm shorter when the zoom is at 28mm. The 28mm has a 49mm filter thread while the 28-60 has a 40.5. The 28mm is two stops faster than the 28-60mm but has a lot of vignetting.

DxoMark says the 28/2 will resolve 47 megapixels when coupled with the A7RIV 62 megapixel sensor.

The lens has quite a bit of distortion but not as much as the 28-60mm and also strong vignetting.

Sony FE 2/28 Mounted Front

On the A1 the lens looks small and well proportionate to the camera body. Not sure if I will ever use a 28mm prime but I got my copy from Wex photography using a discount code and it was open box.

Sony FE 2/28 Mounted Side

Port Required

The lens will vignette with the Nauticam flat port 45 and it requires the purposely designed flat port 32. This was released after the new generation of Sony housing as replacement of the flat port 37 used on earlier models.

Nauticam N100 Flat Port 32

Not much to say the port is obviously shorter and does not focus a knob.

Flat Port 45 vs 32 Perspective

Flat Port 45 vs 32 Side

Topside Comparison

Before taking the camera in water I wanted to make sure the lens was sharper than the 28-60mm and it is.

My assessment topside is that the lens is best at f/5.6 and the 28-60 never really matches it. At f/11 the resolution drops and the two lenses become comparable however there is no benefit shooting the 28mm at smaller apertures than f/8.

Sony SEL28F20 topside f/5.6

SEL2860 Topside F5/6

You can open the images in a new tab I spare the crop comparisons the 28-60 edges are blurry at f/5.6.

SEL28F20 Topside F8

SEL2860 Topside F8

By f/8 there is an improvement at the edges but the centre drops on the 28mm. Likewise on the 28-60mm where the edges become acceptable.

SEL28F20 Topside F11

SEL2860 Topside F11

At f/11 the lenses are almost identical. This is an important consideration as underwater this means shooting from f/11 and smaller aperture will not show substantial differences between the two lenses with the WWL-1.

Pool Tests

I set up my camera and went to Inspire Luton for a shooting session.

First I set up the small test reef and took images at various apertures.

I disabled distortion correction so there is a little black bar on the bottom when you are at extreme close range.

SEL28F20 F5.6 Front

The image at f/5.6 shows that on the focus line (the pink coral is the target) everything is good quality as you move to the edges but you can see the depth of field running out as you get closer. Do not confuse this with the lens edge performance as many testers do.

SEL28F20 F5.6 Edge

The focus point is on the line Achieve Neutral Buoyancy. You can see that the WWL-1 deteriorates the image quality especially on the meridional lines compared to topside. However this is overall useable in my opinion compared to the 28-60mm.

SEL28F20 F8 Front

Closing to f/8 achieves overall the best centre performance.

SEL28F20 F8 Edge

Edges are more than adequate I would say f/8 is the sweet spot of this lens for shots that are not too close.

At f/11 the WWL-1 in its best performance at the edges but the lens has lost a bit of punch.

SEL28F20 F11 Front

SEL28F20 F11 Edge

Here is a shot at f/16 just to demonstrate the issue of depth of field is unrelated to the lens aberrations.

SEL28F20 F16 Front

Personally I would not use this lens for close up work but if you have to f/16 is the way to go.

For reference this is the 28-60mm at f/11 which is totally usable, the shots are not as close so less demand on the lens.

SEL2860 F11 Front

SEL2860 F11 Edge

Shooting a target further away demonstrates the ability of the 28mm at wider apertures.

Tile Wall SEL20F20 F5.6

Edges are fine at f/5.6 but this is a flat target.

Tile Wall SEL20F20 F8.0

In conclusion my recommendation for the 28mm is to shoot the lens at f/8 and go to f/5.6 when there is nothing in the edges as necessary to improve centre sharpness. This is an improvement of 1 stop over the 28-60mm. It is not possible to use the lens at f/4 with the WWL-1 the performance is just not there.

Divers Example

The lens has a good contrast and pop.

Fly SEL28F20 F8

Gauge SEL20F20 f8

Octo2 SEL28F20 F8

Sharing SEL28F20 F8

Shots at f/5.6 are softer at the extreme edges and depth of field also plays a role.

Knee down SEL28F20 F5.6

Midwater shots do not display significant issues as expected.

SEL28F20 f5.6 Diver Side

Open Water Shots

I used this lens in Sorrento during my last trip shooting it always at f/8 which was a mistake for close up shots where I should have closed down the aperture.

The shots that follow would have been better suited to a fisheye.

Gattuccio Egg

Vedetta

In salita

At close range I did not close down to f/16 so the lack of depth of field is evident. Do not confuse this with edge performance.

Spugne

Cucu

You can see that as the focus is on the grouper the reef coming outwards is blurred due to lack of depth of field.

This is very apparent on this shot.

Cernia in crociera

I have the impression that those water contact optics work better when focussed closer in the frame not on the target as if the depth of field is mostly behind the focus point.

Wrap Up

The Sony 28/2 costs £339 currently and the flat port another £369 for a total of £708 for the set up.

I have not tested the lens with the WACP-C but I think performance will be worse as the mount has a lot of gap until the back of the lens is reached and this creates other side effect.

I believe that the 28mm prime is not something that you require for a 24 and even 32 megapixel camera. Users of the A1 or A7R series that want the absolute best quality and the ability to shoot one stop more open will look into this lens but the majority of shooters will stay with the 28-60mm as their only lens. For video users I think the 28/2 lens is a non starter and I am not planning to use it at all as in 16:9 the extreme edges are cropped and even the 28-60mm is fine.

Nauticam WACP-C vs WWL-1

I am conscious that a post like this is destined to create some stir, however it reflects over one month of testing of the two Nauticam water contact optics with my A1 and summarizes my conclusion for my own use.

Of course if you are reading this you may agree with what you will read and this will be your conclusion too. Or otherwise you would have bought the WACP-C thinking it was an upgrade for your Sony Alpha and well if it turns out it is not you will think it is anyway.

I was fortunate to be able to borrow the WWL-1 DRY from Alex Mustard. This lens is the prototype of the current Nauticam WACP-C. The lens has remained pretty much the same but it now has an integrated fixed float collar and built in extension. Other than a thickening of the rear lens mount ring it looks identical and therefore I assume optical performance is the same.

Someone will say well but it is not the same, but as we know the construction of the WWL-1, WACP-C and WACP-1 is identical and each model is 1.15 bigger than the previous with the optical design made of 6 lenses in 5 groups for all of them.

I have not had the chance to test the WACP-1, Alex said he would lend me that too however I am not interested in such large lens.

I have also had the opportunity to test the WACP-C with a variety of lenses including some not on the port chart like the Tamron 20-40 F2.8 and 17-28 F2.8 both did very well but nothing amazingly better than that little Sony 28-60 or the Sony 28mm prime and therefore I concluded that path is not worth pursuing.

Sony SEL2860 Lens Options

For the purpose of this article I will focus on the comparison with the Sony SEL2860 F4-5.6 28-60mm which is no doubt not an amazing lens but it happens to be pretty sharp from 35mm onwards. It is rather weak at 28mm at the edges so one of the things I wanted to check was if the larger WACP-C was giving an improvement over the smaller WWL-1.

Sony FE 4-5.6/28-60 Side

The Sony SEL28060 is a small lens that needs to be extended for use. When mounted on the A1 is pretty compact, no surprise as this is the kit lens for the A7C.

Sony SEL2860 Mounted Front

The lens is longest at 60mm but only 1mm shorter at 28mm which makes it ideal for use behind a wet lens.

Sony SEL2860 Mounted Side

To use it on the Sony E-Mount Full frame of new generation with the N100 port system you need the flat port 45 that comes with a rather unuseful knob that I have removed from mine.

Nauticam N100 Flat Port 45

Nauticam WWL-1 on Sony A1

The set up with the A1 is very compact and portable the whole housing, wet lens camera, strobes and arms together with camera and lens fit a carry on luggage on every airline of the world.

To use the WWL-DRY aka WACP-C I needed to use my 35.5 N120 to N100 adapter and a 25mm adapter ring. The production version only needs a 30mm N100 extension ring but will be as long as you see here.

WWL-1 DRY with float belt

There is a considerable difference in weight between the two set ups and the production WACP-C is heavier.

I own the original WWL-1 version with non integrated float collar which is lighter than the current WWL-1B.

Nauticam WWL-1

In the post title image you see both lenses without floatation.

Pool Tests

In order to perform a comparison I decided to use a semi scientific method consisting of a fixed scene and shots at very close range. The closest the subject is to the lens more stress is induced on the optics that are designed to focus far away. This means that if a lens is better than another at close range when you point them far way the gap will still be there but will reduce.

WACP-C

The first set of tests was performed with the WWL-1 DRY.

CFWA f/5.6 WACP-C 2860

I started at f/5.6 not f/4 that looked visually a waste of time. First I tried with the target on a line to see the potential effect of field of curvature and other issues.

At f/5.6 the sides are already blurry. The edges are even more fuzzy.

EDGE f/5.6 WACP-C 2860

The images are 6 megapixels feel free to open them in another tab and look for yourself.

Edge WACP-C f/5.6 2860

Moving to f/8 improves the situation but not as much as you would think.

CFWA f/8 WACP-C 2860

The edge remain soft at f/8.

Edge WACP-C f/8 2860

EDGE f/8 WACP-C 2860

From f/11 we have good performance across the frame using the SEL2860.

CFWA f/11 WACP-C 2860

Edge WACP-C f/11 2860

EDGE f/11 WACP-C 2860

Note that the focus point is on the edge and this means the issue if solely due to the water contact optic is not a problem of depth of field or field of curvature.

I proceeded to shoot at f/11 and f/8 avoiding f/5.6.

Look here

Maddy tells them off

Shooting at f/8 is possible if there is nothing at the edges and the depth of field is sufficient.

Maddy side

WWL-1

The test with the WWL-1 brought practically identical results.

Sides are soft at f5/6 and the slate shows obvious issues of depth of field.

SEL2860 F/5.6 Front

SEL2860 F5.6 Edge

Edges are very similar to the WWL-1 DRY perhaps a bit better.

At f/8 the situation improves as it had happened with the WACP-C.

SEL2860 F/8 Front

SEL2860 F8 Edge

From F/11 image quality is consistent across the frame.

SEL2860 F11 Front

SEL2860 F11 Edge

There is an obvious issue of depth of field so if you are shooting at close range with the 28-60mm you really need to look at f/16 but this was not the point of the tests.

f/11 side shot

David f/8

Diver f/10

Wrap Up

As you can see by yourself there is really nothing between the two optics and clearly the difference between the wet and dry version is simply in the ergonomics and of course the price. For me there is no reason to consider the WACP-C unless you have serious issues with a wet mount.

After all those tests I decided not to take the WACP-C to Italy and used the WWL-1 for both photos and video with good results.

Puolo -40

This shot is taken at 40 meters with the 28-60mm at f/11.

I pretty much used f/11 fixed changing other parameters for the exposure and at time using the zoom.

Andrea

This is not the red sea it is much darker and as you can see dry suit were in use.

Bavosa Ravvicinata

The zoom of the 28-60 has some clear benefits.

Conclusion

The WWL-1 needs the bayonet mount and the flat port 45 to operate with the WWL-1. This comes at cost of $2,119.

The WACP-C needs the N100 extension ring 30 to operate. This comes at $3,426.

If you a Sony full frame E-mount user and have issue dealing with the bubble removal of a wet lens when you jump in the water you can spend $1,306 to avoid yourself the inconvenience. However you will not have any benefit in terms of optical quality and you will be carrying more weight.

For video the wet lens is clearly preferred as you can operate the 28060 with a flat port and wet lenses for close up work.

The WWL-1 remains the true Nauticam master piece and a lens that keeps delivering years after the introduction.

WACP Prototype Experiments

Few days ago Alex Mustard popped in to drop his WWL-DRY aka WACP-C prototype so that I could conduct some experiments for the enjoyment of the entire underwater community on Sony E-mount.

This lens is not the same of the current WACP-C but it is very similar. It does not have a float collar, a bit like the original WWL-1 dimensionally appears a few mm different from the WACP-C specs.

The lens seems a bit shorter.

140 mm length instead of 145 mm of current production version

The dome diameter is identical somewhere in the region of 130mm.

Dome port perspective masks the real diameter of 130mm

The lens is very heavy in water so I needed some floatation.

Stix float belt carved to fit a dome

I rented a Tamron 28-75mm G2 from lenspimp only to discover it would not fit any of my extensions. Alex Tattersal has sent me an adapter on loan but it did not make it for my pool session.

I therefore decided to use my Tamron 17-28mm although the extension was 5mm too long I got no vignetting at 26mm.

Ready to dive

I exchanged notes with Alex who told me he tried all sorts of optics with his Nikon only to use a 1990 lens now discotinued as all modern fast lenses would refuse to work properly. I was determined to try anyway confident I would get good results.

Pool Tests

Arrived in Luton for a short one hour session last night I took my usual props. The first set of tests show already some interesting results.

I always start as close I can get to the props to fill the frame.

CFWA f/5.6 T28

At f/5.6 the centre is very sharp however I noted the background and were not particularly crisp while the centre was but not in the background. There is an issue of depth of field so I started stopping down the lens.

CFWA f/8 T28

By f/8 results were already very good considering the shooting distance. Consider that a shot like tha requires f/16 on a fisheye or rectilinear to have sufficient depth of field.

By f/11 we are in a really good place.

CFWA f/11 T28

The depth of field is not quite enough for the plant in the back but the edges are sharp.

To show that this is a genuine depth of field issue look at this shot at 17mm in APSC.

17mm APSC f/5.6

It looks very much identical although this is even wider at 25.5mm equivament.

The second step is to look at edge sharpness the pool provides a nice tiled wall for this purpose. Here am shooting at around 1.5 meters.

You can see immediately that the frame is sharp throughout at f/5.6

wall f/5.6

Moving to f/8 improves edges

wall f/8

f/11 brings better edges but in my opinion not the best centre.

wall f/11

This reflects very much the nature of the master lens which is outstanding in the centre at f/5.6 with so so edges but very good on both accounts at f/8. F/11 starts showing an overall resolution loss.

I then moved to test field of curvature.

grid f/5.6

The lens has virtually no field of curvature and the edges are good already at f/5.6.

grid f/8

By f/8 the result is excellent.

grid f/11

At f/11 better edges but slightly worse centre.

Having completed the lab tests it was time to shoot some divers however I was coming to the end of the hour and they had started surfacing!

group f/5.6

Shots at distance with f/5.6 look great.

surface 3 f/5.6

Consider the shutter speed is low as I was trying to get some ambient light and the subject far so there is some motion blur.

surface f/5.6

f/8 is probably the sweet spot for underwater use.

Wide f/8 T28

group f/8

F/11 is really not needed unless you have a close up shot.

Self Potrait f/11 T28

Conclusion

There are some obvious strengths to the Tamron 17-28mm which in my view performs at 28mm way better than the Sony 28-60mm even with a too long extension.

Upon reflection I have decided not to invest on the Tamron 28-75mm as I already have thr Sony 24-70mm GM2 and there is an overlap topside.

Edit 8 April: I received today the adapter ring I needed for the 28-75mm G2 and unfortunately there is vignette at 28mm ruling this lens out entirely for the WACP-C.

If you want to use the Tamron 17-28mm with the WACP-C you need an N120 to N100 25mm adaptor ring, in addition to the zoom gear (not necessarily unless you want to shoot also APSC) and the 35.5mm N100 to N120 port adapter.

The Tamron 17-28mm costs $799 on Amazon.com and it is the best rectilinear wide angle for underwater for the e-mount and we now discovered also compatible with WACP-C.

I will try other lenses in due course but the lesson learnt is that if you do your homework you will find something.

Thanks to Alex for the loan and bear with me a little longer!

Going Macro with Sony A1 and 90mm Macro Lens

I must admit Macro photography is not exactly my favourite genre both underwater and topside however I do enjoy a bit of critter hunting.

I was sure that the A1 would be an absolute beast for topside wildlife and underwater wide angle, however I did not feel comfortable at all with the performance of the Sony 90mm Macro lens.

It has a reputation for hunting and a lot of focus breathing that make it hard to use for topside focus stacking.

I have been playing with the lens topside and I did see examples of both so I was somewhat skeptical taking it underwater.

Camera Settings

I was perhaps over worried so I set up the camera for the worst case scenarios:

• Focus limiter set to 0.3 – 0.5 meter
• CAF priority set to Focus
• Aperture drive – Focus priority

I went in with autofocus set to tracking flexible spot.

Port and Focus Gear

I have always mixed feelings for focus gears and mostly I use it to make sure I am hitting the minimum working distance and therefore maximu magnification.

Nauticam 37147 SE90-F focus gear for Sony 90m f/2.8

The focus gear for this lens is a large item and does not allow to operate the focus clutch. The operation is quite easy as the focus ring does not have an excessive long run.

I already own the 45 Flat Port that I use for the Sony 28-60mm and also have the 35.5 N120 to N120 port adapter so I thought how do I make this 105mm long?

Nauticam 21325 N120 to N100 25mm port adaptor

Nauticam makes convenient adaptor rings of various length to go from N120 to N100 port size. I got the 25mm that resulted in a saving of £441-260=£181 which I used to buy another part.

The rig as assembled looks like this. In effect even the 110 port starts wider and gets narrower.

Sony A1 Nauticam Macro Rig

Before going to the pool I realised the housing does not have an M10 mounting point but you can adapt one of the points that go to the bars connecting the angle. Will be done at some point. So I went in without focus light in a very very very dark pool.

Pool Session

As I packed my props I realised I did not really have any good macro target however a friend came to the rescue. An instructor of a diving center that uses the same pool brought a small leopard and octopus that sank and were perfect targets.

As you probably know I am obsessed by obtaining the absolute maximum performance from each lens. And this for a macro lens means shooting at the best aperture, for this lens f/4-5.6 and stacking. However this is not available underwater. You need to pull your shot from a single image and this means the lens won’t be at the best performance.

I started at f/11 which gives a respectable MTF50 and to be honest I am impressed!

Octopus f/11 angle

Tiger coming f/11

I then pushed the lens to f/16 I could see resolution dropping as depth of field was going up.

Octopus front f/16

Tiger side f/16

In order to get depth of field of an overall scene with the octopus I had to go all the way to f/22 diffraction zone.

Tiger f/22 side

Octopus wide f/22

Yes with the high resolution of the sensor those images are still ok or at least so they seem to me.

Tiger Bokeh f/2.8

I think this lens wide open makes an amazing bokeh that will probably be still there at f/4 so something to check.

Field Impression and Ergonomics

First of all I did not regret setting the lens to close range using the focus limiter. This will give you a frame 19 cm wide if you feel that is too small and you are just trying to get some fish portraits perhaps leaving this to full is a better idea. Likewise if your targets are bigger.

I did not get any hunting despite the dark conditions and I am not sure if this was due to this setting or if this helped.

CAF worked in all situations the A1 can practically see in the dark however in order to get focs tracking and eye detection working (it detected the eye of the leopard) I needed to switch on the focus light of the strobes.

I believe tracking and detection requires a level of scene brightness higher as the camera is effectively in video mode. When you half press the aperture drive meant it would focus thought it had not tracked anything. I got 2 shots not focussed on the subject because I moved.

The focus gear I believe is not required unless you want to do super macro or to make sure you are as close as you can get but I do not regret having it as the run is pretty short with the focus limiter is on.

Conclusion

Alex Mustard tried the 90mm with the A1 for blackwater and said it was better than the Nikon D850 with the 60mm which is a well known blackwater combination. My tests confirm this combination is very very powerful even in the dark and with a little bit of light it will focus on anything. If the lens goes back and forth is because you are close or over 1:1 reproduction ratio.

Overall my concerns apperad not justified and this combination is a solid performer. Probably next steps are getting an SMC magnifier to push this even further.