Big macro lens testThere are heaps of different close-up (or macro lenses as they are also called) diopters available for an underwater photographer. Which one to choose can be easy or difficult depending on which way you look at it. If you just need to shorten your focusing distance to gain more magnification, you can slap any old piece of magnifying glass on the top of your lens and it will help get you closer and you’ll still get nice quality shots. However, if you would really like to know which lens is the best and gives you the greatest “magnification” you need to be prepared for some detective work as the manufacturer’s markings for the lenses can be misleading. Some of them are marked with focal lengths and some with dioptre values and on top of that the refraction of water will alter the lenses capabilities.  And that is the reason I decided to test the most popular and widely available close-up diopter lenses on the market today. They include the following

F.I.T Achromatic +8
F.I.T Achromatic  +16
Inon UCL-330
Inon UCL-165 M67
Inon UCL-165 LD
Reefnet Subsee +5
Reefnet Subsee +10
Olympus PTMC-01

French manufacturer Dyron also promised to send me their lenses for the test but in the end nothing ever arrived. If they ever send their lenses as promised I might still include them in this test in the future.

If you are reading this you probably already have an idea what these lenses are used for but here’s a quick re-cap if you’re in doubt. Underwater, things can be small…very small indded. To get pictures of the smallest critters in an underwater environment that can be unpredictable, macro photographers usually have their BC-pockets packed with some extra magnification for their already close focusing camera lenses.  Where the close-up diopters come in really handy is the compact camera situation, where your lens is not really suitable for underwater macro photography.  Typically today’s compact cameras focus really close once you pop them into the macro mode. The problem is that it will do this only when the lens is in its widest position. This will mean you will need to push your cumbersome housing and flash set-up so close that only the most brainless underwater critters are not bothered. Additionally you and your housing will cast a nasty shadow over the poor subject and you’ll never get it lit-up properly even with an expensive external strobe system.  What you really want to do is ignore the camera’s macro mode and zoom out to the maximum tele-position your lens allows and then add an external close-up diopter that will help the camera to reduce the minimum focusing distance. Normal camera lenses are not designed to focus very close when at the tele-position, hence you need all the help you can get to cut that focusing distance. So in the end you arrive at the nice equilibrium of having your 3x or 4x zoom lens out to its max 100mm or so position and with the added close-up dioptre your minimum focusing distance in now 10 to 20cm from your unsuspecting objective instead of 2cm. And you’re still getting at least the same magnification as before. As an added bonus, with a compact camera system that has a port that accepts lenses, you can often change between a macro dioptre and a wide-angle lens during a dive as the lenses are wet interchangeable.  Now that is a situation you really want to be in, maximum flexibility.

Close up lenses ready to go.. BTW. Its not Inon sponsored test.. I just happen to have a pretty cool Inon towel from Japan :DThis lens test was done in my little test tank with Olympus E-PL3 camera inside the PT-EP05l housing. The lens used was the stock 14-42mm zoom lens in its 42mm position which equates to a focal length of about 85mm. The aperture was set to f5.6. The dioptre lenses were measured from their closest possible focusing distance hence the actual distances the pictures are taken from vary roughly in the order of the given lens magnification (I’m not claiming this lens test is scientifically accurate but it should give you a reasonably good idea of what the main differences are between the lenses).

Out of pure interest I also tested two F.I.T +8 lenses stacked together to see how it would affect image quality. Lens stacking is quite a smart way to be prepared for different size subjects during a dive. All of the macro lenses in this test, apart from the Subsee +5 and +8, can be stacked as they have threads on both ends.

Please note that the Inon UCL-165LD lens was used with a Nauticam 67-LD adaptor.

Here are the test pictures:

1 F.I.T Achromatic plus8

F.I.T Achromatic plus8





2 F.I.T Achromatic plus8 times two

F.I.T Achromatic plus8 times two





3 F.I.T Achromatic +16

F.I.T Achromatic +16



4 INON UCL-330




5 INON UCL-165 M67















8 SUBSEE +10



9 Olympus PTMC-01

Olympus PTMC-01


























Please draw your own conclusions from these images. But here’s a small summary.

Best corner sharpness and least amount of fringing: first place goes to the Olympus PTMC-01 lens. This lens is also the least powerful of the bunch which might explain the quality. Positions 2 and 3 go to the Subsee +5 and +10 lenses. Both of these lenses with their high magnifications are really sharp and show only small amount of fringing.  The rest of the group follows further behind with quite visible fringing in all of the lenses. Generally all of these lenses have good image quality and are very useable in everyday macro situations. Interestingly putting two F.I.T +8 lenses together does not visibly deteriorate the image quality.

The lens with the highest magnification is the Subsee +10, which is no surprise. The Inon UCL-165 is the second with the F.I.T +16 and the Subsee +5 hot on its heels. The lowest magnification is theOlympus. Here the manufacturer’s markings don’t seem to make sense anymore.  The dioptre value of +16 with the F.I.T lens in real life does not magnify as much as +10 of the Subsee. The F.I.T +16 is actually closer to the Subsee +5 than anything.  You have to keep in mind that the Reefnet’s SubSee lenses are quite different from the rest of the group. They are much chunkier and it looks like the actual magnifying lens is sealed inside two flat pieces of glass. This kind of flat glass or port causes any lens to magnify underwater so I’m guessing the Subsee lenses gain quite a bit extra because of the effects of refraction.

Finally we come to the price. Here’s a quick list in descending order
– F.I.T +16 £280.00
– Subsee +5 and +10  £219.00
– Inon UCL-165 LD £180.00
– F.I.T +8 £180.00
– Olympus PTMC-01 £165.00
– Inon UCL-165 M67 and 330 £160.00

Conclusion:  F.I.T +16 lens is bit overpriced for what it does in comparison with the Subsees. After that, the Subsee lenses are more expensive than the remaining  group but the the difference is not that big any more. They will give you the best combination of high magnification and great image quality. Their only down side is the stackability issue; the Subsees can’t be stacked. Diving with two lower magnification lenses that can be easily put together underwater offers a great advantage during a dive as you don’t really know what kind of creatures you are about to face. Having, for example, a F.I.T +8 and a +16 with you is a great way to be prepared for all possible situations. The choice is yours, take your pick as all of these lenses work reasonably well.

Thank you Ocean Leisure Cameras for the Inon and F.I.T lenses, Alex from Underwater Visions for the Subsee and Olympus UK for the PTMC-01 lens

Have a look at some new tests I did including the new Inon UCL-100:


  1. Great job but you do not consider actually using the products in the field. I find the Subsee very heavy and difficult to light the subject due to the size. I think that is an important point.

  2. Jim Anderson says:

    Well done.
    I have used the SubSee +5 and +10 now for 11 months on my Nauticam NEX-5.
    Great lenses and I have not found any problems with lighting or use in the field due to weight. All screw thread attach dioptres can be a bit awkward with gloves in cold water but I like the size of the Subsee making it easier to hold with gloves.
    I wish they could be stacked. I’ve tried stacking by holding the +5 over the +10 – it’s a bit fiddly but produces excellent results.

  3. Jussi says:

    I could see that in some tight situations where you could not position your lights nicely “around” the subject the subsees would cause more issues… shadows and whatnot. Never used them underwater thou… I’ve always had either Inon or F.I.T.


  4. Keri Wilk says:

    Thanks for a great review, Jussi!

    A couple of things I’d like to point out about the SubSee lenses:

    1. We chose not to include a thread for stacking them because the +10 SubSee already provides such a high level of magnification. Going beyond +10 underwater yields working distances which are just too small to work with. For example, a TRUE +15 underwater (unlike the FIT lenses which have specs only valid on land), will give a working distance of 2 inches, and a minimum focus distance of 0.1 inches. That just isn’t enough room to get light onto the subject, so we eliminated that feature in development, reasoning that it would frustrate more people than it would help.

    2. The SubSee system is a completely different optical design than any of the others mentioned here. The +5 is a 2-element achromat, and the +10 is a 4-element achromat, both which are sealed between optical glass windows. This means that they retain all of their power underwater, so the power designations (+5 and +10) are accurate both above AND below water. The F.I.T. lenses, on the other hand, are indeed +5, +8, and +16 diopter lenses on land, but underwater they become +2, +3, and +6 diopter lenses, respectively. So, in order to get the same power as the +10 SubSee, you’ll need to stack all 3 of the FIT lenses together…

    3. Regarding Alex’ comment above about the SubSee being too large to allow easy lighting of subjects. This has nothing to do with the size of the SubSee. When using external diopters, higher magnification means shorter lens-to-subject distances, and more difficulty with lighting. Since the +10 SubSee is the most powerful by far, there is a tendency to attribute the lighting difficulty to its size, but that is not the case. If you stack all of the FIT lenses together, and try lighting a subject, you’ll encounter the same difficulty. That being said, it really is not difficult lighting subjects with the +10 SubSee.

    Sorry for the long comment – just had to clear these few points up! Thanks again for taking the time to write this review.


  5. Thanks Keri,

    I certainly don’t take away from the image quality and magnification of the Subsee. I think the images we have seen demonstrate the high quality of your product.

    I’ve found a great solution for the difficulty I was having with lighting to be the Sagadive fiber optic ring flash. Very much worth a look.


  6. Alex Tattersall says:

    Actually, I think I have realised why I was finding it difficult. I was trying to use the +10 with the 60mm macro lens.

  7. Jeremy says:

    Thanks for this great info, although I think adding the actual magnification of each would be useful. I am torn myself as to which to put on my E-PM1. I am leaning towards the SubSee +10 as I like SMALL things, but a bit concerned with working distance. Wonder what is most versitile when I want to take pix of small frogfish, pygmy seahorses, and ~3-6″ seahorses. I use these as examples of the types and sizes of things I like to shoot the most. Using stock 14-42 Oly lens.

  8. Peter says:

    Have you used the Epoque DML-2 u/w close-up lens ? The specs on Epoque’s website don’t give a Diopter measurement, but I believe it to be in the +8 region on an underwater basis. Any comments on image quality (particularly image sharpness and presence/absence of chromatic aberration), magnification, depth of field, and/or ease of use?

    Many thanks,


    • Jussi says:

      I’ve never properly tested the Epoque close-ups. Along they years I’ve gotten the idea that they are not exactly high quality but I don’t have any first hand experience. Quite bulky they are compared to most other macro lenses.

  9. […] Adam, Thanks for this, I found a good review on the Deepshots site DEEPSHOTS BIG UNDERWATER CLOSE-UP LENS TEST | Deepshots Where did you get your +5 from? only found the +10 on the Ocean Leisure website, the other sites I […]

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