Super Macro 1.7:1

Underwater Video Tips: Choosing a Close Up Lens for a Compact Camera

There is always a lot of confusion around macro photography and close up lenses. It is useful to set some definitions right before going into selecting the appropriate lens.

In traditional terms a macro photograph is one where the image of the subject on the sensor is the same size of the subject itself. As photography is based on 35mm film this means that a macro photograph is one where the vertical size of the frame measures 24mm. If we look at high-end compact cameras there are very few that are able to capture an area smaller than 35×24 mm, among those the Canon G15 or the Panasonic LX7. Majority of other cameras capture around 60-65mm wide and 40-42mm tall frames usually at the widest end with distances of 1-3 cm from the subject. As compact camera sensors are small strictly speaking there are no compact cameras on the market that can capture an object as small as their sensor.

So as far as we are concerned all that matters is that the height of the frame is same or smaller than 24mm as if we were shooting with a full frame DSLR.

Seems macro but it is not!
Seems macro but it is not! 1:1.2

For an SLR user the choice of a close up lens is quite straightforward as usually there will be a 100mm lens behind a flat port. This lens gives a magnification of 1:1 usually with a closest focus distance of 12” or 30cm. To achieve more with the same lens there is the need of a close up lens that works with a similar principle of a magnifying glass.

A close up lens will have a determined focal length or maximum working distance, beyond which it will not focus. If you hold a close up lens at the focus distance and look inside it you will notice that the object will appear larger as you step back from the lens and smaller as you get closer to it. The camera lens behaves in a similar way. Once you reach the working distance of the close up lens is the zoom that moves the lens forward or back and effectively provides the magnification. The close up lens only shorten the working distance allowing you to get closer.

Close up lens are measured in diopters this is the ratio between 100cm and the lens focal length. So a lens with a focal length of 20cm is a +5 diopter. A 100mm lens at 30cm once placed at 20cm from the object would achieve a 1.5:1 magnification. So with a 100mm lens in a flat port and a +5 diopter we are able to capture images larger than life-size with a DSLR full sensor. A +10 diopter would give a magnification of 2.1:1.

So how much power do we need to shoot macro with a compact camera? Is it the same than with a DSLR? Are there other considerations that apply?

The first issue is that because compact camera have fixed lens there is no way to predict at a given focal length if we will achieve macro or not. A compact camera zoomed to 100mm equivalent is not the same as a full sensor camera with a 100mm lens: in most cases the capture area is much larger. In fact there is no way to know if our lens will or not achieve our objective of taking a macro shot just looking at the camera specs. To make matters more complicated it is not always possible to get too close to our subject, this may be because there is no physical way to get closer or because we do not want to freak out the marine life that we want to capture. In general I like to leave some breathing space to subjects, as a minimum 3 inches or 7.5cm are needed and a bit more. This means that more than a lens with more than 12 power is generally a bit too close to the subject.

So how do we work out what diopters we need for our lens? Unfortunately we will only know after we have actually tested it, this is of course not very good!

Another possible approach is to define what is the working distance that we can realistically sustain with our equipment and the conditions we dive in.

Generally it is always possible to get between 20cm and 10cm and in some cases also under 10cm. This corresponds to 5 – 10 diopters and sometimes more for example 12. Considering that plenty of marine life is actually one inch or larger to capture a frame where the subject is filling it we do not actually need real life-size macro. In practical terms this means that for a compact with zoom of 100mm a lens with 6 diopters is fine with less or more depending on the camera zoom and focus ability. So for general purpose a close up lens between 5 and 7 is perfectly fine, this corresponds to working distances between 14 and 20 cm or a bit less from the back of the close up lens so actually closer from the front of the lens itself. For very small subjects around 1.5 cm like a pygmy seahorse we would be looking at 10 to 12 diopters, more is impossible as we would be crashing into the critter. This means a working distance between 8 and 10 cm or 3 to 4 inches from the front of the lens or 3 to 5 cm or 1 to 2 inches from the close-up lens that would still allow a small space for our lights.

Macro Shot 1:1
Macro Shot 1:1

Will we achieve real life size macro with this? It depends, to give some context my Panasonic LX7 that only has a 90mm zoom will capture a 32mm tall frame with 6 diopters power, strictly speaking this is not macro, and 20mm with two stacked 6 lenses achieving a 1,2:1 super-macro.

Super Macro 1.7:1
Super Macro 1.7:1

There are also other consideration that apply, if all we have is a +10 diopter we need to get very close to our subjects for our lens to start working, in all those situation where we cannot get close we would run into problems. If we look at a videographer with a 10x 400mm zoom camcorder they most likely only need a 2-3 diopter because with the range of zoom available they can comfortably achieve macro staying over a foot away from the subject. So the advice is to always have a 5-6 lens for general work and another 10-12 for smaller subject or if the lenses are stack-able two 5-6 this will cover all possible situations with a camera with a 90-140mm equivalent zoom.

I thought of concluding this blog with some recommendations so those are my recommended close up lenses based on personal use or looking at pictures of others:

  • DSLR: Reefnet Subsee both 5 and 10 with 100mm lens on full frame or 60mm on 1.5x cropped sensor. The new Inon UCL100 is also worth checking but it is more expensive.
  • Compact Camera: Inon UCL165 x2 or Dyron Double Macro lens x2

Note that the Inon UCL165 focal length of 165mm is from the back of the lens so the power is 6.06. Dyron lens are reported as 7 diopters however they are then declared 165mm underwater which is actually 6.06 exactly as the Inon.

Optical quality of both lenses is similar so I guess it depends on price what would be the choice. Inon is available with bayonet mount that maybe a big advantage for some cameras like the Sony RX100.

Whilst the Subsee give the best optical quality they are bulky and not flexible so I would not consider those for a compact rig. Inon and Dyron are lighter and more portable and can be stacked, a single diopter will be in most cases sufficient for good close up work with two required only for the smallest critters. It has also to be considered that at least for stills chromatic aberration can be removed in the editing phase, not so for video, but there generally goes unnoticed unless is really heavy. The Dyron and Inon lenses have the level of quality that the aberration cannot be noticed. This muck diving video has plenty of macro and close up with diopters note that no chromatic aberration is visible, shot with single or double Inon UCL165

There are other brands like FIT or époque but there seems to be quite some confusion as their specs are either air values or magnification that as we appreciate depends on the lens used. From tests I have seen the FIT 16 seems less powerful than an Inon 6 and same of a Subsee 5 and they are expensive so not an option for me.

What other tips are useful for shooting with close up lenses? The first is to make sure to use small apertures to have the maximum depth of field.

Contrary to what many believe the diopter itself does not create an issue of shallow depth of field is the size of the subject and the magnification that create the problem. With diopters most times we are at the maximum possible magnification with a total depth of field of few millimeters, it is important to operate at aperture values for a compact camera of f/8 and if available smaller.

For pictures is it also advised to use very fast shutter speed to avoid motion blur that the shake of the camera could create, usually 1/250 or faster unless using a tripod or a solid base. Video is not usually shot with high shutter speed, if available use double frame rate and shutter of 1/100 or 1/125 depending on the PAL or NTSC video system. This will allow half speed slow motion in editing that could prove useful.

Lights are also very important for close up, for still cameras they allow the camera to focus and for video they are needed to actually take the shot. For still cameras a strobe is essential, as video lights do not perform well at high shutter speed.

A final advice is to use the lowest ISO or gain available to ensure the quality of the picture or footage is the best possible, as we are close and have lights this should not be an issue at all. Most macro stills are shot in manual, for video if a manual mode is not available pumping the lights up results in the camera closing the aperture and reducing the ISO. If manual mode is available it is possible to set shutter, aperture and ISO and then measure the exposure that the light give until a satisfactory value is achieved.

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20 thoughts on “Underwater Video Tips: Choosing a Close Up Lens for a Compact Camera”

  1. Thanks, this is great information…..does this mean you have an LX7?? If so what is your opinion of the LX7 good and bad

  2. Thanks for all your research in the use of AD lenses on 28mm cameras.

    I am about to buy the Sony RX100 and a Ikelite housing (trying to keep the cost down).

    I got the Inon 105ad and 3xUCL165ad and would be thrilled to be able to use all of them on the new setup.

    The ikelite housing has a 67mm thread and I will need an adapter in order to use my lenses. Would I need a custom build adapter for this or can I just buy a 67mm–AD adapter for $20?

    Keep up the good work!

    David

    1. Hi David
      For the lenses you have you need a mod kit otherwise the lens would touch the port. This can be built on the adapter you want to buy as the lens don’t need alignment the cheaper adapter is a good starting point. Once you get it you can measure the space between the thread and the port and then I could prepare the mod. Unfortunately I don’t have access to an ikelite myself. Let me know how you get on and if you need help

      1. I was going through my stuff and I got an adapter already made for the AD lenses, the version for the UWL105AD/UCL165AD (the fisheye dome would not be aligned). Would you be interested? It is £30 plus postage. Let me know.

  3. “I believe the 67 to AD should work on the Ikelite – you can use a simple 67mm o-ring to keep it from going too far if needed. Please understand that the 105AD will NOT work well with an RX100 – the sensor and lens are much too large for it – you would have to zoom too far just to prevent vignetting and gain no quality wide angle imaging. I would only recommend an Inon H100 Type 2 28 M67 or LD mount designed for this kind of camera – the Ikelite port is not as close to the lens as the Nauticam, so you won’t get quite as wide angle. The 165 AD will work with the RX100, but it is helpful to understand that the RX100 can be pretty hard to shoot macro with – it takes a lot of patience.”

    If I understand this right is the distance between the lens and the front of the port longer on the Ikelitehousing than it is on the Nauticam and the 105ad on a Ikelite will Vignett and not so much on the Nauticam….

    My 105ad will be useless on the Ikelitehousing and useful on the Nauticam:(

    If it is as above the difference in price is reduced by half and since I would need a new wideanglelens.

    Is the Sony FX100 so hard so shoot macro with as stated in the quote?

    1. Who said that?
      I have used the uwl105ad for all my videos you can see the results by yourself
      And no you can’t use an oring unless you want to loose the lens the thread needs to be fully screwed in when you unlock the bayonet
      There is difference between theory and practice I have compared the image quality with the uwl105 that by the way stops vignetting at 33mm and the uwl-h100 they are the same. The corners are soft because the rx100 has soft corners anyway
      It is true the Nauticam housing has the port closer to the thread and is a better housing. An inon uwl-h100 costs $500 this justifies buying a nauticam housing if you have as lenses

    1. Yes, I had two for the RX100 when I shot the pygmy seahorses. Three you are probably hitting them as focal lenght is 55mm so once you account for the lenses you are on top of the critter?

  4. I will buy the adapter from you. Can you Contact me through my flickr account?

    One more question: How long does it take to charge the battery through the camera?

    1. David
      I will send you an email re the adapter
      For what concerns the battery my recommendation is to buy a separate li-ion universal charger and have two batteries. With one you can do in excess of 3 dives even shooting video you leave the other in the charger and when you swap your old battery gods on charge in this way you need not to wait and have the camera out of use

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