Which Diopter?

These days it is pretty hard to choose from all the diopters available – you probably have at least one old school one in your kit bag.  The Inon UCL 165 and 330 were the first mass produced diopters specifically for underwater use, before those we had to use slide on single element diopters (woodys diopter), or put a higher quality dual element diopter directly on your lens before you got in the water (Nikon 6T).

The most popular models we see visiting through our camera room are the Subsee +5/+10 and Nauticam CMC/SMC, all of which we happen to have onsite, so today we did a little test run on the housereef with various cameras.

For SLR users, the other old way to get more magnification was to use a teleconverter – this would keep good working distance, but would slow down your autofocus and mess with your FStops. It also meant that you need extension rings and additional focus gears if using Manual Focus.  The big plus there is the additional working distance as diopters reduce working distance in order to achieve higher magnification.

This makes it much harder to light your subject, and increases your chances of inadvertently bumping into your subject. This starts to become a big problem with the more high powered diopters being manufactured these days.  Not to mention the additional weight right on the end of your lens which can cause hand strain and additional bumps to wildlife.  If you’re using a heavy and expensive diopter you can afford the float arms! Go buy some and save some damage to the reef!

This being said, the big advantage to a wet diopter is that you can add and remove it as you please along the dive, add a flip holder and you can do this even faster (at the expense of more weight, float arms!).

In the old days the quality of diopters was poor, so even though they were more convenient, teleconverters were still preferred by pixel peepers due to fringing and pincushion distortion on older wet diopters.

The Subsee range of diopters changed this perception on a large scale with their +5 and +10 diopters which have good glass coating, good coverage and can be stacked.  I would consider these diopters the benchmark lenses due to their pricepoint, image quality and build quality.

The newer Nauticam range of CMC, SMC1 and the newest SMC2 all have great sharpness, very little distortion and generally excellent build quality.  But, they are more expensive than the subsee range (~50% more).  Little things that you will start to notice when you use these lenses are creamy bokeh and lack of distortion in the corners.

For testing these diopters the only fair and informative way to do it was to use a variety of cameras with as many constants as possible. If we just use one camera it makes it hard for the user of a different camera to relate. Here’s our camera list for the experiment:

• Full frame (Canon 1Dx),
• Crop frame (1.5 Crop, Nikon D500)
• Mirrorless (2x crop, Panasonic GH4)
• Large Sensor Compact (Sony RX100V)
• Small sensor compact ( Olympus TG4).

We’re missing a Canon 7Dmk2 (1.6x Crop) but you’ll have to forgive us for that.

For Diopters, we used:

• Subsee +5
• Subsee +10
• Noodilab Moby
• Nauticam SMC 1
• Nauticam SMC1 Multiplier
• Nauticam CMC
• Nauticam SMC 2

We went out on the housereef (Simon, Kelo, Johan) with these cameras and diopters to make a simple test on some coral, and here’s what we came up with.  Please bear in mind that these images were never intended to be art.  They are not individually edited (except for sensor dust removal on the GH4).  They were batch processed with the same contrast, clarity, saturation and brightness in Lightroom.

With regards to choosing diopter options for your next macro photography trip, it really comes down primarily to budget – if you’re shooting with a compact or mirrorless then you’d probably start with a CMC and then later on add something stronger.

If you’re shooting SLR then you’ll definitely want a subsee +5 and then one of the other 4 stronger options, likely starting with a SMC1.

There are some problems with fringing on some of the diopters, so we will be doing some more dives over the next week before coming back for part two of this little experiment where we will look at diopter quality using only one camera to give consistent results over a variety of subjects.