I get this question a lot. Many people see cool macro photos with a pitch black background, which almost look like an underwater studio. Would you like to know the secret? Here it is! (hint – you will need a strobe, or at least the on-camera flash)
Method 1 – Night Dives:
Shoot at night! This is a no-brainer. Shoot at night and the background will naturally be black.
This method still requires shooting from the right angle, to make sure you don’t light up the background. Make sure there’s nothing behind your subject for at least a few feet. Shooting from below is an excellent method to guarantee that.
Method 2 (Compact cameras):
Diving during the day? No problem – use a fast shutter speed! When using a flash (strobe), the shutter speed affects only the background / ambient light. This is because the flash is super fast and isn’t affected by shutter speed at all.
You can control the brightness of your background using the shutter speed only. Set the ISO at a nice 100, aperture according to your desired depth of field, and the shutter speed on 1/2000s or even faster if your camera allows it.
That should completely get rid of the ambient light in your background, you still have to obey the same rules I mentioned above – make sure there is no close background behind your subject by lowering your angle.
Method 3 (DSLR’s and Mirrorless):
Unfortunately, due to an annoying technical limitation called “Maximum flash sync speed” (more on this here), you can’t use a fast shutter speed on cameras with a mechanical shutter, which is the case on most if not all DSLR and Mirrorless cameras.
You are usually limited to 1/250s or even 1/200s or 1/160s on some cameras. In this case, you have to lower the amount of ambient light by closing down your aperture and lowering your ISO. Use the lowest ISO available, and close the aperture to F/20 or even more. Then use a very strong strobe, set it on full power, get as close as you can to your subject, and shoot away. If you’re lucky, you’ll get enough light on your subject and no light in the background. Positioning the strobe close to the subject helps a lot.
Creating black background shots isn’t always easy, but it’s worth it. The results are beautiful and your friends will be astonished that you took this underwater!
Quick tip from the pro’s – your background doesn’t have to be a perfect black. A quick adjustment of the ‘Blacks’ slider in Lightroom will finish the job and add some nice contrast to the image.