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A common octopus out for a stroll on a sandy bottom. Most of the macro subjects I like to shoot are on the larger size, subjects that don’t benefit from the use of diopters. Shooting a 50mm macro lens behind the curved port gives me a perfect field of view for critters like this octopus, allowing for easier framing and focusing closer, meaning less water between the lens and the subject. (Sony a1, Canon EF 50mm f/2.5 Macro, Isotta housing, Curved Macro Port, dual Kraken KR-S40 strobes, f/4, 1/250s, ISO 100)
 

In a day and age when the Nauticam MFO-3 exists, it is fair to wonder whether there is still a place for shorter focal length macro lenses in underwater photography. Why bother diving with a dedicated 50mm or 60mm macro lens when a 100mm or 105mm macro, paired with the MFO-3, can effectively give you both focal lengths on the same dive?

It is a reasonable question, but there are still compelling advantages to using a short macro lens underwater, specifically when paired with a curved macro port. In fact, this combination can offer image quality and shooting characteristics that even a versatile long macro setup cannot fully replicate. Understanding those advantages can help you decide whether this type of setup deserves a place in your gear bag.

Traditionally, flat ports have been the standard choice for underwater macro photography, and for good reason. They are simpler and less expensive to manufacture than domed or curved ports, making them more affordable for photographers. Flat ports also allow the use of external diopters, which remain one of the most popular ways to increase magnification underwater.

My custom curved port, mounted on a Nauticam Z8 housing. The glass element itself is cannibalized from the Zen port for the Olympus 9–18mm lens. Those ports pop up with some frequency on used sites or eBay, but Zen does still manufacture them as well. My port was built around that curved glass by Isaac Szabo to work optimally with the Nikon AF-S 60mm f/2.8 Macro lens. This combo achieves remarkable image quality, much better than a 60mm lens behind a flat port. Friends have found other solutions, using glass from an old Subal port, while others got their hands on Nauticam’s own curved port before they discontinued it. Still others have taken the glass from AOI ports or wet lenses and built those domes into their own custom macro ports. 3D printers and ingenuity are not in short supply these days!
 

However, a curved macro port—essentially just the front slice of a larger dome port—can significantly elevate both the technical quality and overall look of your macro images when paired with a short macro lens. Unlike a flat port, a curved port restores the lens’s natural field of view underwater, allowing it to behave much more like it does on land. At the same time, it minimizes many of the optical compromises introduced by shooting through a flat interface in water.

These compromises include chromatic aberration, reduced edge-to-edge sharpness, lower overall contrast, and the smeared or “smudgy” corners that are often visible in images captured with short macro lenses behind flat ports. By correcting many of these issues, a curved macro port can produce images that appear cleaner, sharper, and more natural, particularly when shooting wider macro compositions or subjects that benefit from environmental context. An added bonus is that compositions that would be compromised normally are now available to you, such as a subject positioned near the edges of the frame or the ability to shoot at much wider apertures without losing image quality or sharpness. While the MFO-3 is a fantastic option and very good optically, it doesn’t quite match a properly made curved port for image aesthetics.
 

Flat port vs curved port: The image quality of the top photo, shot with a Nikon AF-S 60mm f/2.8 Macro behind a flat port (f/10, 1/80s, ISO 100), is noticeably less impressive than the image quality of the bottom photo, shot with a Canon EF 50mm f/2.5 Macro behind a curved port (f/4.5, 1/320s, ISO 250). My curved port setup allowed me to create a satisfying small-in-frame image that gives some context to the jawfish, while giving the option for a composition with the subject near the edge of the frame, but not suffering any water-induced optical issues (click the boxed areas for a zoomed-in view)
 

For photographers who value maximum image quality and a more refined rendering style, a short macro lens behind a curved port remains a highly capable and often underappreciated tool in underwater photography. While curved macro ports can be difficult to find, there are used options on the market from Nauticam, Subal, and Zen, all of which can be repurposed for use with modern rigs. Read through the captions of the examples below to find out how I use a curved macro port and why I continue to use one, even alongside the Nauticam MFO-3.
 

A banded jawfish aerating a clutch of nearly-ready-to-hatch eggs. While a longer macro lens would typically be more conducive to a close-up image like this, because the image quality provided by the curved port is so good, I chose to shoot my Sony a1 in crop mode behind the curved port vs shooting my 105mm. I would wager that the only lens or lens setup I’ve shot that surpasses a 50mm/60mm lens behind a curved macro port is the Nikonos RS 13mm (Sony a1, Canon EF 50mm f/2.5 Macro, Isotta housing, Curved Macro Port, dual Kraken KR-S40 strobes with snoots, f/13, 1/320s, ISO 100)
 

An added benefit of a wider macro lens, especially when the topside field of view is restored by a curved port, is being able to give more context to your subject. Instead of punching in tight on this anemonefish, I could still be close while retaining a wider view and getting lots of good textures from the anemone (Nikon Z9, Nikon 60mm f/2.8 Macro, Nauticam housing, Curved Macro Port, dual Retra Maxi strobes, f/9, 1/50s, ISO 100)
 

Wunderpus can be quite difficult to photograph. They are long and spindly and often isolating just the head is the classic way to shoot one. With my curved port setup, I could fit the entire animal in the frame without being a mile away. The more water you have to shoot through, the less detail, texture and color you’ll retain (Nikon Z9, Nikon 60mm f/2.8 Macro, Nauticam housing, Curved Macro Port, dual Retra Maxi strobes, f/8, 1/60s, ISO 64)
 

A robust ghost pipefish locking eyes with the camera. While the ghost pipe is clearly the focal point of the frame, the wider field of view provides some context and you’re able to see the Halimeda algae this fish was blending in with and the wide aperture separates the ghost pipe. Razor sharp focus on the eyes is the icing on the cake (Nikon Z9, Nikon 60mm f/2.8 Macro, Nauticam housing, Curved Macro Port, dual Retra Maxi strobes, f/4, 1/100s, ISO 64)
 

Perhaps my favorite animal on Earth, the blue-ringed octopus. After an encounter with this beautiful cephalopod with a 105mm and diopter, the next time we went looking for her, I chose my 60mm and curved port. I opted for a softer touch with a wide aperture and a small-in-frame composition that would’ve been largely impossible with another setup. Diversity in a portfolio can be reason enough to add a piece of gear like a curved port. Even nearly wide open, the eye of the octopus is razor sharp (Nikon Z9, Nikon 60mm f/2.8 Macro, Nauticam housing, Curved Macro Port, dual Retra Maxi strobes, f/3.3, 1/125s, ISO 72)
 

In addition to the stellar image quality, the wider field of view provided by a short macro lens and a curved port means you can get physically closer to larger subjects like this polkadot batfish. The benefits are twofold: First, you shoot through less water, which improves details, color, and clarity. Second, being closer means you can maneuver your strobes into more positions for interesting lighting, like cross lighting, where the subject needs to fall between the flash heads to be effective (Sony a1, Canon EF 50mm f/2.5 Macro, Isotta housing, Curved Macro Port, dual Backscatter HF-1 strobes, f/10, 1/320s, ISO 100)
 

Double eye contact with a lined seahorse! One of my favorite styles of image is a small-in-frame macro picture. Long macro lenses require you to be too far back than ideal for this type of shot or, if using a shorter macro lens, you lose image quality, especially with subjects towards the edge of the frame. Neither is an issue with the 50mm and a curved port, even at wide apertures (Sony a1, Canon EF 50mm f/2.5 Macro, Isotta housing, Curved Macro Port, dual Backscatter HF-1 strobes, f/5, 1/40s, ISO 100)