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Striated frogfish, Florida, USA: My absolute favorite combination for macro shooting was the Nikon 60mm macro with the Kraken Sports KRL-08S on Nikon full-frame cameras. It provided good magnification, incredible sharpness, and an appropriate working distance to shoot larger subjects without any of the optical issues that can normally plague shorter macro lenses behind flat ports underwater (Nikon D700, Nikon 60mm macro, Nauticam housing, Kraken Sports KRL-08S, dual Retra Flash, Retra LSD snoot)
 

A tool that has become a crucial piece of gear for contemporary underwater photographers is a diopter. When diopters first came into use, they were magnifiers that weren’t ideally suited to shooting through water. However, in recent years, companies like Nauticam, ReefNet, AOI, and Kraken Sports, to name a few, have produced some incredibly high quality water-corrected optics for macro shooting.

Kraken Sports is known first and foremost for underwater lighting products, but the company has an entire line of underwater lenses as well. Kraken’s first diopter was the KRL-05S. It produced high magnification (+13) but the overall image quality was not quite on the level of similar lenses like the Nauticam SMC-1 or AOI UCL-09PRO. I don't shoot a lot of supermacro, so this lens not being spectacular didn't bother me much as I rarely had a need for it anyway.

Then Kraken unleashed the KRL-08S +6 diopter, and in the years since, it had come with me on almost every single macro dive. This water-corrected diopter is phenomenally sharp, can be used on a wide variety of lenses, and produces enough magnification on certain lenses for many supermacro uses while also allowing for better image quality on larger subjects than a macro lens without the diopter added.
 

The Kraken Sports KRL08S +6 diopter
 

A miniscule lined seahorse photographed with the KRL-08S: Shooting with the diopter, there is noticeable difference in sharpness and detail compared to using a macro lens on its own (OM Systems OM-1, Olympus 60mm macro, AOI UH-OM1 housing, Kraken Sports KRL-08S, dual Sea&Sea YS-250)
 

An image of the above seahorse captured without a diopter to show scale
 

The KRL-08S is a hefty chunk of macro glass, heavier than one might think given its relatively modest magnification. It features optical glass elements and coatings on both front and back of the lens, which give top-notch image quality. The KRL-08S sports 67mm threads on the rear of the lens to thread directly onto flip adapters or macro ports as well as 67mm female threads on the front of the lens to stack more macro lenses or attach accessories like a ring light. It is important to remember, as with all optics or ports underwater, to completely dry off both sides of the lens after use so that water does not sit on the glass and stain it. Glass can be polished, but often polishing can remove optical coatings along with water stains.
 

When paired with longer focal length macro lenses like the Olympus 60mm (120mm full-frame equivalent), the KRL-08S is still capable of impressive magnification for pictures of itty bitty subjects like this spinyhead blenny, Florida, USA (Panasonic Lumix GH6, Olympus 60mm macro, Nauticam housing, Kraken KRL-08S, dual Backscatter MF-2 strobes with Backscatter OS-1 snoots)
 

It often seems people want the most magnification and go for the strongest diopter they can find. While there are uses for strong diopters, I actually prefer the weaker powered ones, as I find them much more versatile and applicable in far more situations. My favorite subject matter is generally not the smallest of the small, where a diopter like the Nauticam SMC-1/SMC-2 or AOI UCL-09PRO would be best. I prefer larger subjects like frogfish and seahorses, at least here locally. With a stronger powered diopter, I would only be able to shoot extreme closeups of these animals. I possibly would not be able to use the diopter if I wanted to shoot full body images of the subject.

I find that the KRL-08S, when paired with shorter focal length lenses like 50mm or 60mm gives me the working distance to shoot larger subjects, with the image quality improvements you get from a water-corrected optic. Short macro lenses are known to have optical issues, especially chromatic aberration and “smearing” towards the edges of the frame when placed behind flat ports underwater. The KRL-08S corrects for these problems and renders them essentially nonexistent.
 

One of the few dives I neglected to bring my KRL-08S and I found this small striated frogfish. It may be tough to see here, but the edges of the frame are smeared and blurry with the bare 60mm lens. Compare this to the image below, which was photographed with the exact same setup, but with the KRL-08S added (Nikon D4s, Nikon 60mm macro, Subal housing, dual Sea&Sea YS-250)
 

Every single chromatophore is visible and razor sharp in this closeup of a brownstriped octopus from Florida, USA. Even details in the extreme corners, which usually fall apart or smear with short macro lenses behind flat ports, are retained (Nikon D4s, Nikon 60mm macro, Subal housing, Kraken Sports KRL-08S, dual Sea&Sea YS-250)
 

Another advantage of the KRL-08S is the absolutely blistering sharpness. Because it corrects for the problems that shooting through water introduces, you increase overall image quality even in the center of the frame as compared to shooting a macro lens without it. It is absolutely on par with the best lenses, such as the Nauticam SMC and CMC series.
 

This three-inch long lettuce leaf slug is the perfect sized subject for the KRL-08S on full frame with a 60mm macro lens: small enough to be able to get close and still fit the entire animal in the frame, but not too small to require a stronger diopter (Nikon D4s, Nikon 60mm macro, Subal housing, Kraken Sports KRL-08S, dual Sea&Sea YS-250)
 

I could have photographed this same seahorse quite easily with my bare 60mm macro, but the image quality when paired with the KRL-08S, even wide open, is much better (Nikon D4s, Nikon 60mm macro, Subal housing, Kraken Sports KRL-08S, dual Sea&Sea YS-250)

Final Thoughts

For those looking at diopters and are unsure where to start, the Kraken Sports KRL-08S is a great choice. Not only is it weaker powered than most other diopters on the market—which will make the learning curve much less steep—but it has optics to rival or beat any other diopter on the market. The flexibility to shoot very small subjects all the way up to critters the size of your fist with one lens is fantastic. It is my favorite diopter and will continue to come with me on every single macro dive.
 

Rainbow nudibranch, God’s Pocket Resort, British Columbia, Canada: A pleasant surprise to me was that the KRL-08S works on the Nikon 50mm 1.8G without any vignetting on crop sensor cameras like the Nikon D500. This combination gives a useful perspective while allowing for phenomenal sharpness and image quality (Nikon D500, Nikon 50mm 1.8G, Nauticam housing, Kraken Sports KRL-08S, dual Retra Flash)
 

About the Reviewer: Matthew Sullivan is a Florida-based wildlife photographer who has been diving since he was 10 years old. He has traveled extensively, visiting well-known dive destinations such as Guadalupe Island, Indonesia and the Philippines, but he also likes to dive closer to home in the Pacific Northwest. When not taking pictures underwater, he can be found trekking mountains, or exploring national parks and rainforests in search of new adventures and wildlife encounters.
 

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