Some of our favorite marine life subjects are best photographed using only ambient light from the sun. Put away the strobes and the video lights, because this two part tutorial reveals how you can capture great ambient light photos.
What is Ambient Light Underwater?
Ambient light is produced by the sun and does not include any artificial light from your strobe or video light.
Ambient light photography is focusing on creating images using just this sunlight, whether you’re on the surface or diving deep.
Why Should I Shoot Ambient Light Photos?
There are several reasons why we shoot ambient, foregoing use of underwater strobes and video lights. The first is when shooting fast mammals like whale sharks and dolphins. Strobes add bulk to our camera rig, slowing us down in the water. The benefit of strobe light for these large subjects right at the surface is minimal, so most divers leave the lights behind in order to streamline and move more freely.
The second instance for shooting ambient light is when we can’t get close enough to our subject for the lighting to make a difference. Think of a massive shipwreck down at 90ft (28m). Our strobe or video light only goes a few feet (2m max), so it’s best to turn them off to avoid potential backscatter when the subject is beyond that range.
The third instance is when the wildlife is affected by the strobes. Some areas even prohibit use of lights on the animals, including the manatees in Florida and humpback whales in Tonga.
Ambient Light Camera Settings
Shooting ambient light underwater requires a different group of camera settings than those for shooting with strobes. One of the nice things is that we have the ability to use more automatic settings. This is because we only have one exposure variable to consider instead of two or more.
A nice side effect of relying more on auto settings is that we can recompose quickly during fast action without manually metering the scene, adjusting exposure and shooting. You can just point and press!
Autofocus is another big consideration when shooting ambient light, and will vary depending on the subject. Back button focus can often prove useful with faster animals.
I like to let the ISO play a little bit when shooting close to the surface, especially if there are clouds in the sky that may dramatically change exposure values (e.g. a cloud blocks the sun and the water is instantly darker). Be sure you can limit the range of your ISO to an upper limit of 320 (compact cameras) or a bit higher on crop sensor and full frame cameras.
Shutter Speed vs. Aperture
The term for shutter priority or aperture priority varies slightly for each camera manufacturer. Each of these semi-shooting modes allows you to determine one exposure variable while allowing the camera to instantly meter the scene and determine the other variable.
I go back and forth in using shutter priority / time value mode and aperture priority mode depending on what I’m shooting, how fast it’s moving, available ambient light, etc. You have two choices though:
You can set a middle aperture like f/5 on compact and f/8 or 9 on crop and full frame. When using this mode, be sure to keep an eye on the shutter speed being selected by the camera. It needs to be high enough that you have no motion blur, usually 1/250 at a minimum.
Alternatively, you can fix the shutter speed (e.g. 1/500) and let the camera select the aperture. For wide-angle ambient light photography you can usually get away with using a wide-range of apertures. And with a fast shutter speed guaranteed, this method is often easiest with fast subjects.
Correcting the Exposure
There are three ways to quickly adjust this automatic exposure if you’re not getting the results you need. If your images are appearing dark due to limitations with shutter speed or aperture, try increasing your ISO.
If your camera is consistently metering the scene too dark or too light, you can try adding 1/3 to 2/3 stop of exposure compensation. This is a quick adjustment on Canon, Nikon, Sony, Olympus and Panasonic. Once the camera meters the scene it will then apply your manual correction on top of the exposure, dialing it in to exactly the way you’d like it.
Lastly, you can also experiment with your metering mode. I generally default to a matrix / evaluative style metering mode that tells the camera to consider all elements of the frame in determining the exposure. Sometimes, however, you may want to try spot metering, for example, when you have a very dark subject in an otherwise very bright background.
Phew! I know that’s a lot and there’s a lot of room for interpretation! If you’re confused or intimidated, feel free to contact me.
Lenses and Dome Ports for Ambient Light
There are a number of different lens and dome port options available depending on your underwater camera system, budget and what sort of shots you’re looking to capture.
There’s also no right and wrong answer in selecting a lens and dome port or wet wide-angle lens combo. You’ll actually need to make some sacrifices. Below are some quick pros and cons with various gear.
Mini Dome on Interchangeable Lens Camera
The mini 100mm (4″) dome is small, light and easy to carry through the water. This dome is almost always paired with a wide fisheye lens, which is ideal for subjects swimming close to you. A negative is that it’s challenging to shoot split-shots with a small dome.
Large Dome on Interchangeable Lens Camera
Large domes allow you to use either a fisheye lens or rectilinear wide-angle lens. They also make it easy (or as easy as possible) to capture split shots, even in rough water. Third, they often offer better image quality in the corners than a mini dome.
As a down side, they are larger and tougher to swim through the water. Large domes, especially acrylic, are very buoyant and can be tough to push underwater when snorkeling and diving below the surface.
Wet Wide-Angle Lens on Compact Camera
Compact camera shooters are more limited in wide-angle conversion lens selection. There are many choices for simple, light lenses all the way through expensive, heavy zoom-through water contact optics.
Learn more about wide-angle wet lenses.
Each behaves a bit different depending on your camera and housing combo, so I highly recommend speaking with your local underwater camera retailer to learn specifics for your system, what you intend to shoot, and your budget.