Advanced Camera Settings for Underwater Photography

So, you’ve started taking underwater photos and they’re turning out pretty good… but you’re ready for more. This article is aimed at people who’ve mastered the basics and are wanting to dive deeper into their camera’s settings and capabilities.

We’ll have a look at perfecting your in-camera settings using ambient light, as opposed to artificial lighting. I like to start here because there’s so much you can learn before you splash out on the more expensive lighting gear.

After reading this, head out on your next dive or snorkel and play around in the shallows with some of these top tips. It's time to break out of Auto!

Aperture

When shooting above the waves, photographers live for that shallow depth-of-field and dreamy bokeh, achieved by shooting with a wide-open aperture (i.e. low f numbers). Underwater, however, is a different story. Water is denser and home to all sorts of particulates which can mess up your autofocus. It is generally advised to shoot with a narrower aperture to guarantee that your subject will be in focus. Depending on your sensor size (from Full Frame to Micro 4/3) I’d recommend somewhere between f6.3 to f9.

Shutter Speed

The key to shutter speed is to find that balance between letting enough light to your sensor while still removing motion blur and capturing a crisp, sharp image. Most cameras will achieve this around the 1/250s mark but it will depend on the in-built image stabilization and size of your sensor. Play around this level within the same shot to see where your camera thrives.

ISO

The ISO determines your camera’s sensitivity to light. Lower ISO means less noise, but you may end up with underexposed images. I usually leave ISO on auto and let my camera decide what’s best while setting an upper limit of 400-500 so that there’s not too much noise. This is because the surface conditions (e.g. sunny or cloudy) can change very quickly and affect the amount of ambient light available, so it’s just easier to let your camera figure that part out while you focus on other settings.

Exposure Compensation

If you’re finding that your underwater shots always come out darker than you’d like, then consider setting your camera’s exposure compensation up 1/3 or even 2/3 of a stop. This way, once your camera has metered the scene it will add your desired exposure compensation and you’ll end up with a more exposed shot.

Histogram

Another golden rule is to always use your histogram. The histogram is the most useful tool for understanding your true exposure, as opposed to relying on your eyes. All too often, your shot looks well-exposed on camera and then you load it up on your laptop only to find it’s way too dark. This is even more of a problem underwater as your eyes adjust to the lower light. Make sure you use your histogram to properly expose the scene before you press that shutter.

White Balance

This is a feature often overlooked because it can easily be corrected in post-processing when shooting RAW. While this is true, not every detail of your White Balance can be changed in editing software, and it’s much better to get it right in camera. Most cameras come with an ‘underwater mode’ for this reason, and you can always set it manually. You do this by selecting your camera’s Manual White Balance mode and then taking an image of something white at your desired depth; your camera will then adjust to this white balance for subsequent photos. (Remember you’ll need to readjust this every 5-10 feet!)

Metering

Metering is another feature that’s often left on Auto, but it can be a really useful tool - especially underwater. Essentially, your camera assesses the scene to determine the best exposure right before you capture the shot. There are a few different ways it can do this. When shooting a wide angle I generally leave the metering on a Matrix/Evaluative mode as it will expose for the whole scene. However, if shooting a dark subject with a bright background (like a fish or turtle against the surface), switch it to Spot Metering and place your subject on the spot. This will bring out the detail in your subject while dimming the bright background.

Here, you can still see the detail in the turtle despite the very bright background.

Aperture or Shutter Priority?

When using ambient light to shoot underwater, I’ll rarely use full Manual mode as it takes much longer to set-up the shot and is often unnecessary. Depending on the scene, I’ll use either Aperture Priority or Shutter Priority.

For most shots, AP is preferable because it ensures that your subject is properly in focus. However, if you’re trying to freeze the motion of a particularly fast-moving subject (or you yourself are moving a lot in current or swell), you may want to switch to SP and increase your shutter speed to 1/500s or thereabouts. It really depends on your surroundings and definitely needs a little playing around with.

Back-Button Focus

This is one of the most under-used features among amateurs and can really up your photography game. Particularly useful for faster-moving subjects, back-button focus enables you to separate your focus from your shutter. Most cameras use a half-press to focus and full-press to take a shot as default, but they also offer a way to dedicate a button to focus so that you can shoot quickly without refocusing every time. Once you’ve tried it, you won’t go back!

Continuous AF and High-Speed Shooting

Again, these tools are particularly useful for scenes that are changing quickly. By setting your camera to Continuous AF and shooting at the highest frame rate possible, you maximize your chances of getting the perfect shot. Couple this with back-button focus as detailed above and you’re on to a winner.

Review Your Images

Don’t forget to review your images underwater before in Playback mode, before you move on. Zoom in on the important details and change a few settings before trying again. The last thing you want is to have five of the same photograph with the same mistakes and find yourself wishing you’d played around a bit more.

Composition

Lastly, a word on composition. This is not *technically* a camera setting but equally important. If you’re trying to capture a sea critter, remember that eye contact and face-on shots engage people much, more. If shooting wide-angle, get close to your subject - closer than you’d think! - to adequately fill your frame.

The Rule of Thirds is still a good one to follow for underwater shots, but you should also consider what photographers call Swim Space. This means leaving space in front of your subject to draw the eye to where it’s meant to be. The image below illustrates this nicely.

Note the eye of the fish central to the frame and the 'swim space' ahead of it.

I hope these tips on the more advanced camera settings are a useful addition to your underwater photography toolkit - happy snapping!