How to Achieve a Black Background in your Underwater Photography
Achieving a black background in underwater photography is a great way to isolate a subject and create drama within your images. Even though a dark background is often associated with night diving, there are plenty of ways to create this artistic effect during broad daylight.
A clean black background without backscatter can help to emphasise a subject, particularly if the subject has a complex pattern, or is very well camouflaged against the background.
The key to this technique is having control of both camera settings and strobe positioning. This helps the photographer to adjust the settings and block out ambient light, using only the artificial light to illuminate the subject.
1. The basics
Creating a black background is possible with most cameras, whether a DSLR or compact, as long as the camera offers manual control. A macro lens and either a snoot or strobes are also essential pieces of kit, as we need a source of artificial light which we can adjust to be brighter than the ambient light.
For very small subjects I would favour a snoot over a strobe, as they provide greater control when illuminating a small subject, and you are able to see the area which is lit before taking the photograph.
The most important thing to consider when using inward lighting or a snoot to create black background images underwater is that we are trying to cast light across the subject and the foreground, but avoid lighting up the background. We want to keep this as dark as possible.
As underwater photographers, we know that light between the camera and subject can cause unwanted backscatter. So, in order to minimise the amount of particles we are lighting up, it is important to get as close to the subject as possible.
2. Inward lighting
Inward lighting is one of the most successful yet frustrating techniques to use to achieve a black background and a beautifully illuminated subject in the foreground. It involves doing something radical: pointing your strobe(s) at your camera rather than at the subject.
The reason for this is to stop the strobe light reaching the background, so it remains black. Instead, we light the subject with only the edge of the flash beam, and the rest of the foreground will also be illuminated.
Normally, if I am using one strobe with this technique, I will place it above the camera and in line with the subject in the twelve o’clock position. When using two strobes, I favour the ten and two o’clock positions as this keeps the beams of light even. This technique involves a lot of test shots and small adjustments of strobe positioning until you find the sweet spot. Don’t be put off, it does become easier with practise.
3. Shutter speeds
Shutter speed controls the amount of ambient light hitting the sensor within your camera so, when trying to achieve a black background, you must try to minimise the amount of ambient light hitting the sensor.
We can do this by combining a low ISO of 100 or 200, a small aperture to keep the subject in focus, and a high shutter speed of around 1/200th or 1/250th of a second on a DSLR or mirrorless camera. Some compacts can achieve shutter speeds of up to 1/500th of a second.
So, if our high shutter speed is causing a black image, we are going to need a strobe or artificial light source to illuminate our subject. Do remember to check the flash sync speed of your camera, as this will dictate the maximum shutter speed you can achieve.
Read more: What are Shutter Speed and Aperture?
4. How to choose your subject
Choosing subjects for black backgrounds is very important. You want the subject to stand out against the clean black background. Colour and shape are the deciding factors: a bright, colourful subject will have a huge impact on the viewer when placed on this background.
Subjects in open water are great to focus on, especially when trying to achieve black backgrounds for the first time. When the subject is in open water and the background is empty, your flash will only illuminate the subject, thus creating the black background effect.
Fish or other species which perch on corals or rocks can also make good subjects for this technique. Try to find the angle in which the subject is framed against open water for best results.
5. Shooting at night
It seems obvious that creating a black background should be easier at night. The water is naturally dark, strobes are much more focused, and the limited visibility forces you to look for suitable subjects.
One top tip for underwater photography at night is to use a focus light. It won’t affect your overall exposure, but it will help you focus on your subject. You never know what may appear out of the darkness, as marine life seems to be more active and less phased by divers at night. Cephalopods in particular are much more common during the evenings.
Your lights will likely attract many critters, some of which may use your lights to hunt. This behaviour right in front of your lens will give you prime position to capture great images. Most underwater photographers use macro lenses on night dives. It’s the easiest option, especially for beginners, and can guarantee good results.
However, wide-angle is swiftly becoming the more popular option. Although mastering wide-angle at night, particularly on a fisheye lens, is very difficult, it is very well suited to larger subjects such as sharks and rays.
The key thing to remember is that you are using your camera settings to block out all ambient light and create a black background, so you need to also use a flash or artificial light source to light the subject. Creating a black background isn’t just for night diving, as you can produce artistic images with dark backgrounds even in broad daylight, using a combination of a fast shutter speed and low ISO.
Be creative in your photography and look for well positioned subjects that suit the techniques you are using. The ability to create a black background will only improve the quality of your shots, as it’s truly a great way to isolate a subject or enhance their natural colours and patterns.