DPG is a comprehensive underwater photography website and community for underwater photographers. Learn underwater photography techniques for popular digital cameras and specialized professional underwater equipment (wide angle, macro, super macro, lighting and work flow). Read latest news, explore travel destinations for underwater photography. Galleries of professional and amateur underwater photography including wrecks, coral reefs, undersea creatures, fashion and surfing photography.
Dive Photo Guide


Big Dome Split Shots
By Matty Smith, February 11, 2023 @ 08:00 AM (EST)

Nikon Z7II, Nikon 14–30mm f/4 zoom lens, Aquatica housing, NiSi 4-stop graduated ND filter, Matty Smith 12" Dome (f/11, 1/400s, ISO 400)

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 not knowing what lies beneath, the transitional part of moving from one element to the next, that feels so magical, and the thought of what alien creatures I might encounter. That is what draws me to taking over-under images. I try to convey to the viewer that majestic feeling in a picture format. It’s maybe the best way I can communicate to a non-diver what it’s all about, to marry a wet, unfamiliar world with a dry, familiar one. A well-executed split shot also seems to be a great crowd pleaser—it has instant wow factor!

In this article, I’d like to share with you some of the techniques I use for this type of photography and answer some commonly asked questions: What equipment do I need? What are the best focusing techniques? How do I properly light the image? How do I stop water beading? And what is the best time of day to shoot?

Nikon Z6II, Nikon 14–30mm f/4 zoom lens, Aquatica housing, NiSi 4-stop graduated ND filter, Matty Smith 12" Dome, Matty Smith Remote Pole, (f/8, 1/1000s, ISO 2800) (Find out the story behind this award-winning shot here.)


Equipment for Splits

When shooting an over-under image, you are usually creating a half-landscape, half-seascape scene, so common sense would suggest using a wide-angle rectilinear or fisheye lens to capture the entire vista. I will generally use my 14–24mm f/2.8 or 14–30mm f/4 rectilinear lenses for big animals or humans, where I want to control distortion and create a natural perspective. The fisheye lens like my 8–15mm f/3.5–4.5 will be used for reef scenes where the fisheye distortion will normally go unnoticed.

You’ll need a dome port to shoot through: Your usual wide-angle dome port will suffice, something in the region of 8 to 9 inches is fine. A bigger dome makes the job much easier, and conversely, while not impossible to shoot over-unders through a smaller dome, it does make things a little harder. (It also creates some optical problems; more on that later.)

You may want to use your strobes for fill light when shooting into the sun at sunset or sunrise, or to add some color to the reef. If you’re shooting a scene where you can’t stand up, it’s a good idea to add a floatation device to yourself and the camera. I sometimes strap a swimmer’s kickboard under my housing and use an inflated BCD as a raft to lean on. This will prevent you from sinking when you lift that heavy camera out of the water, and it will help you to frame up your shot. Note: Trying to shoot an over-under with your dive gear on your back after a dive is nigh on impossible!

Matty’s rig set up for shooting over-unders: Note the underwater strobe positions and flotation device underneath the housing


Above and Below in Focus

So how do you focus? The quick answer to that question is to set your camera’s focus points low in the viewfinder and concentrate on getting the underwater part of the scene sharp. Then, use a narrow aperture, such as f/16 or above, and the let depth of field take care of the top part.

There are reasons why this is a reliable technique to use. With a half-and-half image, you are basically creating a window into another world where light and focus behave on totally different playing fields, especially when shooting through a curved optic such as a dome-shaped port. The interaction of the curved surface of the port and the refraction of the water create what is known as a “virtual image.” The virtual image appears smaller and proportionately closer to the camera underwater. If we were able to see this phenomenon at play, it would look something like Fig. 1. Here, we can see the camera, the virtual image below the water, and the real image above the water.

Fig. 1: Virtual image

As depth of field always extends much further behind our point of focus than it does in front, we are maximizing our chances of getting a completely sharp image by focusing on the virtual image underwater. However, the smaller the dome port you use, the smaller and closer the virtual image is to your camera and the harder it will be to get under and over parts in sharp focus as the complete image becomes more disjointed. Figure 2 shows some examples of this. All of these unprocessed experimental pictures were taken at an actual distance from the banner of 1 meter and were all shot at f/8 with a Nikon 8–15mm fisheye lens zoomed to the 15mm end.

Fig. 2: Test over-unders with different sizes of dome port

As you can see, when it comes to split shots, the bigger ports generally help to make overall crisper images. The improvement in clarity above the water is noticeably better with each increase in port size. Regardless of port size, your best chance is to always focus on the underwater part of the scene and stop down your lens as much as you can reasonably go with the light you have to work with. With general port sizes of 8 to 9 inches, upwards of f/16 is best.

A large dome port generally helps to create overall sharper images


Balanced Lighting

As usual, lighting falls into two categories: ambient (natural) light and artificial (strobe or continuous) light. When shooting large scenes where artificial light sources will have little effect, it’s generally better to shoot at the brightest times of the day, when the sun is high. However, this can cause exposure balance problems, as the sky is usually several stops brighter than under the water. To overcome this issue and minimize the need for post-processing, I like to use a 4-stop graduated neutral density (ND) filter. This helps to retain sky detail and prevent it from blowing out to overexposure—and also minimizes post-processing.

Nikon Z7, Nikon 14–30mm f/4 zoom lens, Aquatica housing, NiSi 4-stop graduated ND filter, Matty Smith 12" Dome (f/11, 1/320s, ISO 640)

When the sun is lower in the sky and with smaller scenes, strobes can be used to fill in detail underwater. In such cases, I find it’s better to expose for the sky and then adjust strobe power to fill in the darker underwater details.

Nikon Z6, Nikon 8–15mm f/3.5–4.5 fisheye zoom lens, Aquatica housing, single Inon Z-240 strobe, Aquatica 9.25" dome port (f/14, 1/13s, ISO 250)


Preventing Water Beads

Nothing ruins a good split shot more than those pesky water beads on the upper part of your picture. But they can easily be avoided. There are two schools of thought when it comes to preventing them:

  • The Hydrophobic Method: Completely repelling the water from the top of the dome
  • The Emulsifying Method: Creating a thin, even coverage of water over the top of the dome

The Hydrophobic Method

To dispel the water completely from the port, you can use waxing agents such as Rain-X or clear car polish. Rain-X is a product used to wax car windscreens to encourage water and road dirt to roll off it; it does the same thing on a glass dome port. I say “glass” because this method is best used on glass ports. Some products, including Rain-X, may damage acrylic. Once the port is treated with the product, most of the water should roll off when the camera is lifted from the water, a quick shake of your camera should remove any remaining beads before shooting.

The Emulsifying Method

This is my personal favorite method and can be used on both glass and acrylic ports. The best product I have found for this is Sea Drops Anti-Fog. When you smear Sea Drops all over your port, it will emulsify with the water it contacts and create a thin, smooth, even covering of water, just like it does in your mask to prevent fogging. Obviously, fogging isn’t the issue here, but while your port is covered evenly in water, it can’t form into beads. For this method to work, the port needs to be spotlessly clean, especially clean of grease such as fingerprints and sunscreen. Grease on the port will break the water tension across the top of the port and form beads. This method also does a great job of hiding scratches on your port since it’s all wet—essential when shooting into the sun.

Nikon Z7, Nikon 14–30mm f/4 zoom lens, Aquatica housing, NiSi 4-stop graduated ND filter, Matty Smith 12" Dome (f/8, 1/400s, ISO 500)


Best Time of Day to Shoot

If you’re planning on shooting reef or seabed, definitely wait for low tide when there is the minimum amount of water over the coral—ideally 20 inches or less. The first thing I do once I’ve found a location is check the local tide charts and see which day is best for lowest tide at the time of day I want to shoot.

If you’re shooting animals in the open ocean, tide is obviously irrelevant, and the best time of day depends on whether the subject is too big for strobes or not. For instance, anything too big to light with strobes may well be better shot around the middle of the day to maximize light penetration from the sun. But don’t be bummed out if the midday sun isn’t out: The look of heavy cloud in splits adds drama to a picture that a clear blue sky cannot. If your subject can be lit with strobes, shoot at any time to get your desired atmosphere into the image.

Nikon D810, Nikon 16mm f/2.8 fisheye lens, Aquatica housing, dual Inon Z-240 strobes, Matty Smith 12" Dome Port (f/22, 1/250s, ISO 800)

About the Author: Matthew Smith is no stranger to shooting split shots, and his portfolio, “A Parallel Universe: Windows Beneath the Waves” contains a selection of his favorite and most successful over-under images. This collection has won him several highly acclaimed international awards from the BBC and National Geographic, among many others, and worldwide recognition of his unique signature style. His work has been exhibited all around the world, from the London Natural History Museum in the UK to the Australian Museum in Sydney, and he speaks publicly about his style and approach. Matty is a staff photographer for Ocean Geographic magazine and a brand ambassador for Nikon Australia and Aquatica Digital. He produces his own optical acrylic dome ports specially designed for over-unders.


Be the first to add a comment to this article.
You must be logged in to comment.
* indicates required
Travel with us

Featured Photographer