Why Do You Need To Use Huge Custom Dome Ports For Insane Split Shots 2025

Why do you need a large dome port? 

By taking on over under photograph, you are opening a portal into a complex yet rewarding dimension of photography / videography. Submerged things appear larger than they are in reality, due to the water's refraction created by the port's surface. In other words, they seem to be considerably closer. This effect is more pronounced the smaller / flatter the dome port. Therefore, what the camera actually captures underwater is a "virtual" diffracted image that is considerably closer than it truly is. In order to take a sharp picture, the camera must then concentrate on this virtual image.

Usually, when creating a completely submerged image, this is not a problem. However, if you need front to back sharpness in your split shot, it does provide some depth of field issues. The lens being utilised must have a depth of field that can encompass both the actual above-water image and the smaller, closer "virtual" image. To take advantage of depth of field, the majority of photographers use a fisheye or an extremely wide angle lens and stop down to F22. Although it functions well, there are several evident downsides, such shutter speed loss or an increase in ISO. This is especially problematic in low-light conditions and while being buffeted by waves in the open ocean. In these circumstances, faster shooting is preferred.

The refraction increases as the dome port gets smaller. In order to achieve a deeper depth of field, we must increase our f-stop as the virtual image becomes closer. This enables us to sharply focus on both the under and over portions of the image.

How can this issue be solved?
We developed some enormous  10, 12 & 16 inch dome ports for shooting over-under photos. With appropriate apertures and shutter rates, front to back sharpness is now easily attainable (as wide as F8 with a fisheye). Additionally, proportions seem more accurate.  

With an oversized dome port, you can get a narrow, needle-sharp waterline and an equally crisp horizon. Additionally sharp deep into the frame's corners is everything in between. 

The dome port not only improves focus and proportion, but it also provides a number of other benefits.

1. The port is buoyant enough to ride over the swells and seldom ever gets fully submerged when filming in rough, open ocean. This makes it possible for you to be in a decent shooting posture so that you can consistently capture the water and air in the frame while shooting over under. Every frame you shoot should have a great over/under and not completely covered by the under or left high and dry by the over.

2. The dome's buoyancy also helps it support itself in the water, which is another benefit. This implies that you do not have to raise the camera's weight to take a picture. Typically, this causes the photographer to sink, which makes it challenging to frame up. 

3. Our huge dome's increased lens-to-water line distance ensures that the water line in the frame remains thin and unobtrusive. The meniscus of the water line is considerably thicker and takes up too much frame space because it is so close to the lens if you envision a smaller dome. As it won't be sharp either, this can be bothersome. The result is a thin, clean & sharp waterline.

4. You can use lower F-Stops like f4.5, it will allow you to capture It a new kind of image with a blurred background that smaller domes cannot produce.

5. And lastly, the dome works well as a predator shield! The 5mm backing plate and 5mm acrylic dome port gives you a little extra protection during the shoots with crocodiles and sharks.

What are the drawbacks / danger of large dome ports?

1) They are extremely buoyant - you will not be able to dive or freedive with these domes, they are made for split-shots, not underwater footage. 

2) They are MASSIVE! They take up a huge amount of space to store and travel with. 

3) They can be dangerous to use in the waves. Due to the volumetric size of the domes, they act like a small boat when a wave hits the dome, potentially sending the dome hurtling towards you. We don't suggest using oversized domes in large waves.