Split / Over-Under Photography

Also known as: Half-and-half, split shot, split level, over/under, 50/50, above-and-below
Key practitioners: David Doubilet, Franco Banfi, Cristian Dimitrius, Matty Smith, Becky Kagan Schott, Berkley White, Mike Veitch, Viktor Lyagushkin, Allison Vitsky Sallmon, Andy Sallmon
Equipment: Wide-angle or fisheye lens, large dome port (8-10”+), small aperture (f/16-f/22), strobes
Related techniques: Close-focus wide angle, Wide-angle photography

Overview

Split or over-under photography captures both the underwater and above-water worlds in a single frame, with the waterline bisecting the image. The technique produces some of the most visually striking images in underwater photography. As David Doubilet described it: “These images bring the two elements of our planet together. They are especially striking when viewed by people that have never been diving and enjoyed the experience of viewing our treasured ecosystems underwater” (^[1]). Doubilet called the surface “a thin molecular curtain that can create optical magic” (^[2]).

The technique requires mastery of dome port optics, depth of field management, exposure balancing between two radically different lighting environments, and the persistent challenge of water droplets on the dome surface. It sits at the intersection of technical precision and artistic vision — the photographer must simultaneously compose for two different worlds while managing the physics of light refraction through a curved glass or acrylic surface.

Matty Smith, one of the genre’s modern masters, described the appeal: “For me one of the most wondrous parts of any dive is the moment that the water engulfs my mask as my head slips below the surface. I think it’s the suspense of the unknown of what lies beneath, the transitional part of moving from one element to the next that feels so magical” (^[3]).

Dome Port Theory and Optics

The physics of dome ports

Split shots depend entirely on dome ports, and understanding dome port optics is essential to the technique. Julian Scheunemann published a foundational “Dome Theory” article on Wetpixel in 2004 that established the mathematical framework. He showed that the virtual image distance from the dome is calculated as L(inf) = 3.03 * r, where r is the dome radius. For example, a dome with a 10 cm radius creates a virtual image approximately 30.3 cm in front of the dome glass (^[4]). This formula explains why the lens must focus close underwater — it is focusing on the virtual image, not the actual subject.

Paul Kay added in the comments that the virtual image field is curved parallel to the dome surface, and that zoom lenses shift their entrance pupil position across the focal range, meaning a dome can only be optimally aligned for one focal length (^[5]).

Dome size, placement, and entrance pupil alignment

Jean Bruneau and Chris White (CeeDave) published detailed diagrams on Wetpixel in 2005 explaining proper dome placement. The key principle: the camera lens’s entrance pupil must be positioned at the center of curvature of the dome. When this alignment is correct, light rays pass through the dome perpendicular to its surface, avoiding refraction, chromatic aberration, and edge blurring. When misaligned, “rays do not pass through the dome to the lens perpendicular to the dome. This causes refraction, and thus chromatic aberration and blurring…the effect is most noticeable at the edges of the dome” (^[6]).

They also noted a critical principle for split photography: “larger domes have more gently curved image planes and require lower diopters, if any, for focusing” (^[7]).

Why larger domes produce better split shots

Alex Mustard wrote the definitive practical explanation of dome port optics in his 2014 review of the Nauticam 140mm dome. He identified the core challenge for split photography: “above water there is no virtual image,” while underwater “the lens focuses on a virtual image much closer to the camera.” Large domes create a virtual image that is farther from the dome and less tightly curved, making it easier to keep both the underwater virtual image and the above-water scene within the depth of field (^[8]).

Mustard emphasized that photographers should “always focus on the underwater section of the scene and use depth of field to ensure the above water view is in focus,” because “depth of field extends twice as far behind a subject than in front of it” (^[9]). This is why split shots that mistakenly focus on the above-water portion invariably produce blurry underwater sections.

He also provided a historical note: “The earliest domes were all small. In the early 1960s both Schulke and Starck pioneered the use of hemi-spherical domes, independently. Realising the limitation of their small domes sourced from boat compasses, they dreamed of larger domes if only they could be made” (^[10]).

Sensor format and dome size relationships

Mustard established practical minimum dome sizes for each sensor format when using fisheye lenses:

• Micro Four Thirds (2x crop): 80mm dome with 8mm fisheye
• APS-C (1.5x crop): 100mm dome with 10mm fisheye
• Full frame (1x crop): 150mm dome with 15mm fisheye

Smaller sensors use shorter focal lengths for the same field of view, providing more depth of field at any aperture, which means they can use smaller domes and still achieve acceptable corner sharpness. Rectilinear lenses require larger domes than fisheyes for comparable performance (^[11]).

History on Wetpixel

Early dome port coverage (2004-2006)

Wetpixel’s coverage of dome port optics — the technology underpinning split photography — began with Julian Scheunemann’s dome theory article in October 2004 and Eric Cheng’s editorial promoting it (^[12]). The Bruneau/White placement article followed in February 2005.

Key product milestones tracked by Wetpixel during this period:

• 2005: Ikelite released its 8-inch dome port, reviewed by James Wiseman with the Canon 10-22mm lens (^[13], ^[14]). Aquatica shipped an 8-inch dome compatible with Ikelite housings (^[15]). Olympus announced a glass dome port system for the E-System cameras (^[16]).
• 2006: Ikelite released updated details and extension ring (“stalk”) system for their 8-inch dome, allowing one dome to work with multiple lenses (^[17]). Sea & Sea introduced a glass dome port, claiming it “produces clearer and sharper images, reduces glare, lasts longer” and is “better for taking over/under photos” than their previous acrylic port (^[18]).
• 2007: Aquatica announced the 9.25-inch glass “Megadome,” the largest commercially available dome port at the time (^[19]).

The mini-dome revolution (2010)

The year 2010 saw a pivotal shift in dome port design with the emergence of commercial mini-domes around 100mm (4 inches) in diameter. Eric Cheng covered the trend in a February 2010 article, noting Seacam’s 105mm Fisheye Macro port and Zen Underwater’s 100mm dome, both designed for fisheye lenses on crop-sensor bodies (^[20]). Aquatica followed in March with their Mini Dome 100 in BK-7 coated glass, priced at $699 and rated to 90m/300ft (^[21]). Barry Guimbellot published a DIY small dome port design for close-focus wide-angle work (^[22]).

Alex Mustard wrote the comprehensive analysis in “Thoughts on Mini Domes” (March 2010), documenting both advantages and limitations. Mini-domes had “always had a small, but loyal following in underwater photography” among DIY builders, but three commercial options arriving simultaneously marked a turning point. He noted that while mini-domes excelled at close-focus wide-angle photography by allowing strobes to be positioned very close to the dome, they were fundamentally inferior for split shots because their smaller radius creates a closer, more curved virtual image that makes it harder to achieve corner sharpness (^[23]).

Mustard cautioned against treating mini-domes as a new innovation: “all the early dome ports were mini-domes. Big domes were too expensive and difficult to make… The innovation photographers wanted back then was actually to make them bigger, to overcome some of their optical issues” (^[24]).

The Dome Port Diaries (2008-2009)

Daniel Brown wrote the eight-part “Dome Port Diaries” series for Wetpixel, an entertaining and educational chronicle of a newcomer’s journey into housing ownership. Beginning in September 2008, the series combined humor with technical detail, covering water physics, dome port theory, the “housing crisis” of choosing gear, camera-housing-water interactions, the social aspects of underwater photography, and the practicalities of traveling with dome ports (^[25], ^[26], ^[27], ^[28], ^[29], ^[30]). The series made dome port concepts accessible to beginners and drew enthusiastic community response.

DEMA 2011: “Domes without the Drone”

Alex Mustard delivered a landmark talk at the DEMA Show 2011 Imaging Resource Center entitled “Domes without the Drone,” focusing on practical pros and cons of various dome types rather than abstract optical theory. Wetpixel filmed and published the presentation. The community response was overwhelmingly positive, with 19 comments praising it as “the best talk” and “answering 99% of the dome questions I’ve ever had.” Berkley White called it “a great resource to point people to” that would replace the “3-minute chats” dealers typically had with customers (^[31]).

The definitive “Ask the Pros” feature (2015)

The landmark Wetpixel treatment of split photography was the 2015 “Ask the Pros: Split shots” article — a five-page feature with contributions from 16 professional photographers: David Doubilet, Franco Banfi, Cristian Dimitrius, Allison Vitsky Sallmon, Andy Sallmon, Matt Smith, Douglas Seifert, Mike Veitch, David Fleetham, Eiko Jones, Viktor Lyagushkin, David Salvatori, Becky Kagan Schott, Rico Besserdich, Julian Cohen, and Berkley White. Each answered standardized questions about lens choice, dome port size, exposure technique, fast-moving subjects, ideal dive sites, and commercial viability (^[32]).

Specialized applications

• Iceberg splits (2015): Photographer Steve Mandel used a custom rig — a Canon 5D Mark III on a bracket at the end of a 7-foot pole with custom legs resting on a zodiac, controlled via CamRanger iPad app — to shoot split shots of Antarctic icebergs. The work was done under permit since all recreational drone use in Antarctica is now banned (^[33]).
• Water droplet management (2017): Matty Smith, described as a “half and half guru,” published a video tutorial on minimizing water droplets, sharing techniques from his award-winning practice (^[34]).
• GoPro split shots (2015-2021): The technique became accessible to action camera users when KNEKT released the KSD6 6-inch dome port for GoPro in 2015. KNEKT marketed it as democratizing split photography: “Until now one would need to invest thousands of dollars in high-end camera equipment in order to create these images” (^[35]). Inon shipped the “Split Easy” in April 2021 — a simple rubber ring that retains water between GoPro housings and the Inon UFL-G140 SD semi-fisheye lens, enabling split shots with minimal additional equipment. Inon noted that the lens “is originally designed for underwater use only and thus cannot focus on distant objects on the land (air) side when shooting a split shot” (^[36]).
• Micro Four Thirds splits (2015): Forum discussions explored split shots with the Panasonic 7-14mm rectilinear lens behind the Nauticam 180mm glass dome on Micro Four Thirds bodies, with users debating whether the larger rectilinear dome was easier to handle than the smaller fisheye dome despite the distortion tradeoff (^[37]).

Doubilet’s “Two Worlds” book (2021)

David Doubilet published Two Worlds: Above and Below the Sea through Phaidon in September 2021 — his first major book in two decades, dedicated entirely to 80 split-level images shot throughout his career. The book included essays by Kathleen F. Moran and former NASA astronaut Kathryn D. Sullivan. Doubilet explained: “Many people ask me: ‘Are those pictures real?’, ‘Are they made in Photoshop?’, ‘How do you do it?’ and ‘Do you need a special camera?’” Wetpixel editor Adam Hanlon called it “absolutely worth the wait” (^[38]).

The book also served a conservation purpose, juxtaposing photos of the same locations taken years apart to document environmental degradation — coral bleaching at Tumon Bay in Guam between 2005 and 2017, and ocean plastics off the Philippines (^[39]).

Wetpixel Live coverage (2020-2021)

Alex Mustard and Adam Hanlon dedicated extensive Wetpixel Live coverage to dome ports and split photography. Key episodes included:

• Dome Port Choices (August 2020): Hanlon noted dome ports “are also somewhat misunderstood” because “the underlying optical theory of dome ports is somewhat complex, and is hence avoided” (^[40]).
• Dome Port Maintenance (September 2020): Essential tips for maintaining, protecting, and repairing lens ports (^[41]).
• Shooting Split Shots (September 2020): Focused on the perennial forum question of preventing water droplets on dome ports (^[42]).
• Dome Port Choices II (December 2020): A practical discussion covering port size, extensions, materials, and lens choices — with “no physics or optical theory” (^[43]).
• Mini Dome Port Primer (January 2021): Prompted by a forum thread, covering small dome ports’ “unique creative possibilities, reduced cost, and portability advantages, and limitations” (^[44]).
• Scratched Dome Port Advice (April 2021): Even glass dome ports can be scratched; the episode covered prevention and repair (^[45]).
• Dome Port Essentials (August 2021): Addressed topside photographers who “assume that the dome’s function is simply to provide a waterproof port and tend to be unaware of the fact that it also acts as a critical component in an underwater optical system” (^[46]).

A companion article in June 2020 republished the 2015 “Ask the Pros” feature, calling it “the definitive guide to honing your split shot skills” with “literally hundreds of years of experience” represented (^[47]).

Technique Details

Optics and depth of field

The fundamental challenge: underwater, the lens focuses on a virtual image created by the dome port (approximately 3 times the dome radius in front of the dome surface, per Scheunemann’s formula); above water, the lens focuses at infinity with no virtual image. As Doubilet explained: “These pictures must be made at f/16 or f/22 for depth of field to hold up” — he builds images around “f/22, the ‘unmovable’ f-stop” (^[48]).

Mustard formalized the focusing rule: always focus on the underwater section, because depth of field extends twice as far behind the focus point as in front of it. Focusing on the above-water element will “invariably” leave the underwater section out of focus (^[49]).

Preferred lenses and dome ports

From the “Ask the Pros” survey (^[50]):

• Doubilet: Nikkor 14-24mm f/2.8 and 16mm f/2.8 fisheye on Nikon D4/D3S, Seacam Superdome, Sea & Sea YS 250 strobes
• Banfi: Canon EF 15mm f/2.8 Fisheye on 5D Mark III, super dome preferred “better to balance and to keep the right level”
• Dimitrius: Canon 16-35mm for video, 8-15mm for dark waters, Canon 11-24mm (widest rectilinear available — “this lens will be one of the favorites for many shooters”); Zen ZP-230 (9-inch dome) for all split work
• Sallmon pair: Canon 8-15mm fisheye on full-frame, 8 or 10-inch glass dome ports with antireflective coatings to prevent glare

Most pros recommended the largest dome port practical for travel — 8 inches minimum, 9-10 inches preferred. The consensus was that fisheye lenses are more forgiving than rectilinear lenses behind smaller domes.

Exposure balancing

The above-water portion is typically 2-4 stops brighter than the underwater portion. Strategies varied significantly among the pros (^[51]):

• Doubilet: Get exposure right in-camera at f/22. On a bright tropical day: “f/22 @ 1/160th at 200 ISO. Light the bottom of the image with 2 Sea & Sea YS 250 strobes at half or full power. A third strobe maybe used on a long cord.” He emphasized: “Get the exposure right in the camera and you will have a stronger, truthful image”
• Banfi: Close to f/16 minimum, increase ISO for adequate shutter speed, use graduated neutral density filter in post via Camera Raw
• Dimitrius: Add underwater fill light when possible; when using natural light, protect highlights topside and lift shadows below in post. For video, “pay lots of attention to the dark and clipping pixels” since the latitude for post correction is narrower
• Sallmons: “Fast shutter speed and as small an aperture as possible… expose for underwater primarily, toning down the topside section in post if needed”

Water droplets

The most-discussed challenge in the Wetpixel community. Solutions mentioned by the pros (^[52]):

• Dunk and shoot method (Doubilet’s preference): repeatedly submerge and surface the dome — “Dunk & shoot, dunk & shoot”
• Saliva (Dimitrius): “spitting in the dome like to avoid fogging the mask and rubbing it” — works for “one or two shots”
• Baby shampoo and other chemical solutions
• Potato (forum suggestion): rubbing the dome with a freshly cut potato to create a hydrophobic starch layer, though it washes away after a few minutes (^[53])
• Acceptance: Dimitrius noted “occasional drops don’t ruin the picture. In some cases they are part of the shot and in others you can remove with a spot removal tool”

The forum thread on water drops also revealed that Rain-X should never be used on acrylic ports (it can damage them), and that manufacturers “strongly recommend not mixing plastics such as acrylic and lipids (waxes and oils)” as “the plastics can absorb lipid and crack” (^[54]).

Shooting fast-moving animals

The pros offered varying approaches to the challenge of capturing dynamic subjects at the waterline (^[55]):

• Doubilet: Relied on high frame rates (up to 11+ fps) with strobes at quarter to half power to keep up, combined with anticipation: “I try and anticipate the action and make the camera earn a living”
• Sallmons: “The appropriate phrase is ‘spray and pray’… best to prefocus the camera and start shooting early, a split before the subject is where we’d ultimately like it to be”
• Dimitrius: Did not expect “the usual rectilinear line between the two sides of the picture” and instead preferred “a more confused separation that adds movement to the image.” He had shot sharks, birds, dolphins, and “even a swimming sloth, that can be much faster in water than in trees”
• Banfi: Admitted “I don’t remember to have shot a fast moving animal split” and suggested opening the f-stop and using second-curtain sync

What makes a great split shot

Doubilet identified three essential elements (^[56]):

1. A compelling surface — “Get out there and look for it”
2. A dynamic underwater half that “drives the image” — “It needs to be uncluttered and dynamic. Color is always a bonus”
3. Dramatic surface elements — “reflections or a wave breaking across the big dome creating a crystalline effect”

He also noted a practical tip: “In deep water I take off my BC and inflate it to use as a raft for my camera” and recommended avoiding backlight “because it produces too many artifacts and internal lens reflections.”

Dimitrius emphasized storytelling: “I believe they are so popular because they connect the two worlds and you can definitely tell a good story with one single picture” — citing his sold-immediately image of an American crocodile in Cuban mangroves where “the only way to tell this story in one picture was to do a split shot” (^[57]).

Matty Smith approached split photography as landscape work: “I view my half over half underwater images as a landscape photograph; I prefer brooding and atmospheric skies over a blue sunny midday and a composition that compliments both the above and below elements.” He described extensive location scouting with snorkel gear and reference photos before attempting final images (^[58]).

Commercial Value

Multiple pros confirmed split shots sell well. The Sallmons noted that “when we’re considering the proportion of underwater to split images we shoot, they sell extraordinarily well.” Dimitrius described selling a crocodile-in-mangrove split immediately because “the only way to tell this story in one single picture was to do a split shot.” Banfi noted: “I don’t know if they sell well but for sure the editor like them” (^[59]).

Doubilet framed the commercial appeal in journalistic terms: “As a photojournalist I find that a half-and-half picture can anchor a story by giving it a sense of place while bringing underwater subjects to life” (^[60]).

Becky Kagan Schott offered a non-diver perspective on why the images connect: “for non-divers, I think they’re a relatable way to show them what we’re seeing just under the ocean’s surface” (^[61]).

Forum Discussions

Dome port scratches: The 186-reply thread

The Wetpixel forum thread “Removing scratches from a dome port” (started June 2005) accumulated 186 replies over many years, making it one of the most active technical threads in the forum’s history. The original poster, rschrager, reported badly scratching an acrylic Sea & Sea dome port at Cocos and Malpelo islands (“lots of current and lots of rock is a bad combination”) and successfully used the Micro-Mesh NC-78-1 Acrylic Restoral Kit ($37, designed for airplane windscreens) to restore it. Alex Mustard responded in the second post: “Great info, Bob. Its a common question. Now we need something that will work on glass domes too!” (^[62]).

A separate 2010 thread addressed glass dome scratch removal, with users reporting success using jeweler’s rouge and a Dremel tool (suggested by Stephen Frink) and commercial glass polishing kits — challenging the conventional wisdom from opticians and housing manufacturers that scratched glass domes “must be replaced” (^[63]).

Split shots with specific systems

The forum hosted extensive discussion of split shots with particular camera systems. An early 2005 thread by Jean Bruneau (“Viz’art”) documented using the Aquatica 8-inch dome on an Ikelite D70 housing with the Nikon 10.5mm fisheye, demonstrating that “there is an 8-inch dome that will allow split shots like the one we are used to seeing all the time from the aluminum guy’s” — referring to aluminum housing manufacturers like Subal and Seacam (^[64]). The discussion revealed the importance of dome-to-housing positioning: Aquatica’s version moved the dome closer to the housing than Ikelite’s adapter approach, which was critical for fisheye split photography.

Glass versus acrylic dome debates

Multiple threads debated glass versus acrylic dome ports, a decision with direct implications for split photography. Glass domes offered better optical performance, scratch resistance, and reduced glare (important when the above-water portion introduces bright light sources), while acrylic domes were lighter, cheaper, and easier to repair when scratched (^[65]).

Dome Port Timeline

• 2004: Julian Scheunemann publishes dome theory formula on Wetpixel (^[66])
• 2005: Jean Bruneau and Chris White publish dome placement diagrams (^[67]). Ikelite releases 8-inch dome port (^[68]). Aquatica ships 8-inch dome for Ikelite housings (^[69])
• 2006: Sea & Sea introduces glass dome port, marketed as better for over/under shots (^[70]). Ikelite releases extension ring system for 8-inch dome (^[71])
• 2007: Aquatica announces 9.25-inch glass Megadome (^[72])
• 2008-2009: Daniel Brown writes eight-part Dome Port Diaries series (^[73])
• 2010: Seacam, Zen, and Aquatica simultaneously release commercial mini-domes (~100mm) (^[74], ^[75]). Alex Mustard publishes comprehensive mini-dome analysis (^[76]). Barry Guimbellot publishes DIY small dome design (^[77])
• 2011: Alex Mustard delivers “Domes without the Drone” talk at DEMA (^[78])
• 2014: Nauticam releases 140mm glass dome; Alex Mustard publishes detailed review establishing sensor-format dome sizing rules (^[79])
• 2015: “Ask the Pros: Split shots” published with 16 contributors (^[80]). KNEKT releases KSD6 dome for GoPro (^[81]). Zen Underwater updates 230mm dome for Nauticam (^[82])
• 2017: Matty Smith publishes water droplet video tutorial (^[83])
• 2020-2021: Wetpixel Live dedicates seven episodes to dome ports and split photography (^[84])
• 2021: Inon ships “Split Easy” accessory for GoPro (^[85]). David Doubilet publishes Two Worlds: Above and Below the Sea (^[86])

References

Articles

Forum threads

Wetpixel Live