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Quick Tip-Underwater Photography

March 29, 2011

Quick Tip-Underwater Photography
...keep in mind that color effectively disappears underwater, with red vanishing at about 15-20 feet and other colors progressively dissipating the deeper you go.

With its richly colored landscapes and fascinating sea creatures, there are few places more beautiful to photograph than the underwater world. Whether you’re scuba diving among sharks or snorkeling along a reef, the photographic possibilities are endless and intriguing.

Of course, underwater photography can be a little intimidating since shooting underwater presents unique photographic challenges. But you’ll get immediate feedback with your digital SLR so you can make adjustments when necessary and it won’t be long before you’ll be showing off images of your underwater adventures to fellow divers, snorkelers and land-locked shutterbugs. To help you gear up and grab those once-in-a lifetime shots, here are some guidelines and tips to get you started.

Camera Equipment Selection:

Underwater housings are available for many digital SLRs so if you already own a DSLR, the most economical way of gearing up is to find a housing for your current camera. However, if you’re just starting out or are thinking of stepping up to a new DSLR, make sure that a housing is made for your preferred model. Also think about the types of images you want to shoot and the conditions under which you’ll be working.

Perhaps the two most important features to consider are the sensor size and lens selection. If you’re interested in taking fish pictures and macro shots under well-lit conditions (or with a strobe), you’ll be fine with an APS-C sized sensor found in cameras like the EOS 7D, or the Rebel T2i.

If, however, you really want to concentrate on underwater landscapes, shipwrecks or large marine life, you may want to consider a full-frame camera like the Canon EOS 5D Mark II so you can fully utilize the viewing angle of a wide angle lens. One of the goals in underwater photography is to get as close to your subject as possible to lessen the amount of water between camera and subject.

The camera you choose should also offer a full complement of wide angle and macro lenses since these are the two types of lenses you’ll be using most often.

Other considerations when selecting a DSLR for underwater photography include video capabilities, if you like to shoot both still and video and Live View (see below for information about Housings and Live View).

How to Choose an Underwater Housing:

While most camera manufacturers do not offer underwater housing for their SLR or DSLR cameras (Canon does make underwater accessories for most PowerShot models), a variety of third-party companies do. Many of these speciality companies offer dedicated underwater housings, each with different specifications and capabilities depending on the camera they are designed for. Housings are generally constructed of acrylic or aluminum. The former are generally less expensive but are sometimes a little bulkier than their aluminum counterparts and may be a little less durable. Depending on your camera model, you may not have a choice but both materials are perfectly acceptable.

A more important factor to consider is the depth rating. At best, if you take the housing deeper than it’s rated, the camera controls won’t work. At worst, the housing can leak or implode. Consider that, at the surface, air pressure is 14.7 psi (pounds per square inch). Pressure doubles at 33 feet underwater and increases by 14.7 psi for each additional 33 feet of depth. Dive to the bottom of a swimming pool to about 12 feet and you’ll feel the pressure difference in your ears. That gives you a hint about how much pressure your housing needs to withstand to operate at depth. If you’re only going to snorkel, you should be able to get away with a depth rating of about 33 feet (as long as you don’t do any deep free diving). Many DSLR housings have a depth rating of between 200-300 feet, which is deeper than most scuba divers dive but provides a good safety margin for the housing.

After depth rating, perhaps the most important aspect to consider is which controls can be operated when the camera body is in the housing. Check out several different housings to see which one best meet your needs, especially if you plan to use many of the camera’s manual or advanced features. Get some hands-on time with the housing if you can or examine a diagram to see how the controls are positioned. You want control positioning that falls naturally within reach while your hands remain on the housing’s handles.

With the advent of Live View, underwater photographers have another option for composing a shot. Keep in mind, though, that autofocus isn’t as fast with Live View but it does make for easier composing. If your camera is equipped with Live View, test it out to see whether it works for you. Otherwise, you can easily use the camera’s optical viewfinder. Although your eye is separated from the optical viewfinder by the housing and your mask, most housings come with a built-in optical system that provides increased eye relief. This magnification allows you to see the entire image in the viewfinder.  You’ll also need to decide what type(s) of ports to purchase for your housing. Each manufacturer has slightly different specifications and provides a list that matches ports and lenses. Generally, though, you’ll need a dome port for wide angle lenses and a flat port for macro lenses.

Lenses:

For wide angle lenses, the rule of thumb is get the widest angle lens you can afford. Again, you want to limit the amount of water between the camera and the subject. If you’re shooting with a full-frame camera like the 5D Mark II, check out the Canon EF 14mm, and the EF 15mm fisheye, lenses. Full-frame shooters will also make good use of the Canon EF 16-35mm, f/2.8 L II lens. The Canon EF-S 10-22mm is a good alternative for cameras with APS-C sized sensors; keep the zoom as wide as possible to counterbalance the cameras’ 1.6x crop factor.

On the macro side, you also want to position the camera as close to your subject as possible, so the Canon EF 50mm, the EF-S 60mm, or the EF 100mm macro lenses will work well. Of course, you don’t want to scare away a tiny fish or get too close to anything that can harm you. A friend once had a small octopus grab onto her strobe and rip it off the housing—not a common experience but something to keep in mind when approaching wild life of any kind. Another diver found the strobe later that day, abandoned by the curious octopus.

Strobes:

You’ll also need to budget for one, preferably two, external strobes and a set of strobe arms for each. One option is a self-contained underwater strobe, which requires no extra housing and, depending on the strobe, may be more economical than purchasing and housing a standard strobe such as the Canon Speedlite 580EX II.

There are a couple of differences, other than price, that should be noted. Obviously, you can’t use the underwater strobes above water (okay, theoretically you can but they’ll be incredibly heavy) so it might make more sense to house your current flash(es). Another downside is the lack of E-TTL in some external strobes, so examine the specs carefully or be sure you’re well-versed in manual strobe exposure.

Self-contained underwater strobes have a major advantage, however. They cover wide angle lenses while housed strobes do not so unless you plan to only shoot macro, you should opt for a self-contained model.

Underwater Housing Tips:

Before you make your first dive with a housing, be sure to check it for leaks. The best way to do this is to take an empty housing on a dive with you. Yes, it’s a waste of a good dive but it’s better to find out that the housing leaks or you didn’t seal it properly before you put your camera in it.

Pay attention to the manufacturer’s instructions about checking, cleaning and replacing O-rings. Even a little speck of sand or a strand of hair can break a seal and allow water to enter the housing and potentially harm your camera. Be sure to maintain your equipment on a regular basis. .

Thanks to large capacity media cards and excellent battery life, your camera will be good to go for at least a full day of diving (and maybe a night dive, too). But when you need to take the camera out of the housing in between dives, be sure to wipe the housing dry before opening it up so you don’t get drips of water on the camera.

When you’re traveling, it’s unlikely that you’ll be able to fit all your underwater photo gear into a carry-on bag so be prepared with a hard-cover case with TSA-approved locks. Most hard cases come with customizable foam interiors or padded divider system for protection. If you’re concerned about checking everything, carry your camera and lenses on board and check the housing, strobes, strobe arms, and other accessories. At least you’ll have a topside camera if your luggage gets delayed on the way to your island vacation.

Lighting:

Lighting is key in all photography but takes on an even more critical role underwater since light waves are refracted and absorbed as they travel through the water. So, unlike land photography, the best time to shoot underwater is between 10 a.m. and 2 p.m. on a sunny day for the brightest ambient light possible.  Also keep in mind that color effectively disappears underwater, with red vanishing at about 15-20 feet and other colors progressively dissipating the deeper you go. Sure, you can get great images using ambient light but in order to capture the full bloom of color underwater, you need to use strobes.

As we mentioned earlier, two strobes are better than one because, just as in studio lighting, multiple light sources provide more even coverage. And, because strobes are mounted on adjustable arms, you can easily position them at the appropriate angles for different shots.

Straight on lighting, especially with a single strobe, is usually unflattering under any circumstances but causes a phenomenon unique to underwater photography: backscatter. Even the clearest water contains particulates and if you point the strobe straight ahead, the light will hit these tiny floating objects and reflect back into the camera. Rather than a beautiful underwater scene, your image will resemble a snowstorm. So go with dual strobes if you can and watch your angles.

Shooting Tips:

Before you start shooting underwater, be sure you’re comfortable with your camera—you don’t want to try to figure things out when you’re at depth. Also become familiar with the camera’s full complement of manual exposure modes since you may need to adapt your settings to changing environments.

  • You might want to start out in aperture-priority or shutter speed priority (if you’re using manual settings on your strobe, be sure the shutter speed is set to sync with the strobes). If you want to capture an image of a rapidly swimming fish (or diver), be sure your shutter speed is at least 1/100th-1/125th of a second to stop motion. And if you’re diving shallow on a windy day, up the shutter speed to help correct for water motion that may be bouncing you around.
  • Exposure metering depends on the subject you’re shooting, of course. But it’s safe to use center-weighted average or evaluative metering, especially if you’re shooting an elusive (and moving) subject.
  • Autofocus generally works well underwater but if you want to play it safe, get manual focus gears for your housing so you have the option to switch from AF if the scene is too low contrast for AF to work effectively. Canon lenses with their full-time manual focus (no need to switch between AF and MF on the lens) are very good for this dual focus option. Again, you can try Live View although it’s probably best for static subjects like coral rather than schools of fish.
  • While every underwater photographer has his or her own preference for white balance settings, to have the most flexibility, it’s best to shoot in RAW (or RAW plus JPEG). We have to say, though, that auto white balance on the Canon 5D Mark II actually works quite well. Also try the Cloudy white balance preset, which helps cut down on blue casts or bring a small white diver’s slate with you to set a custom white balance.

Composition Tips:

One of the coolest specialty shots is an over/under shot, with half the image underwater and the other half above the water line. The easiest way to achieve this type of image is with a fisheye lens and a dome port (you can use other wide angle lenses as well, but we think the fisheye lens works best). Check to make sure there are no water droplets on the top half of the port when you’re shooting. (Some underwater photographers use Rain-x or Pledge on the port beforehand to help prevent water drops.). The Canon 5D Mark II’s evaluative metering works well for the over/under shots, although you may want to stop down the lens to increase depth-of-field to compensate for the difference in the over/under focus points.

There’s also a more complicated version that entails using a split neutral density filter to balance the over/under exposure and a diopter to compensate for the different focus points. But unless you’re going to specialize in this type of image, you’re better off experimenting with the gear you have.

Try to include a diver in photographs, especially to give scale to large marine life, reefs and shipwrecks. If you’re shooting up towards the surface, use the exposure compensation feature found on all DSLRs to underexpose the shot (bracket if possible). Underexposure can also be used to silhouette a diver or a school of fish against a bright background.

Fill flash is particularly useful underwater. To highlight a coral head or reef against the ambient light background, underexpose the background by about 1 stop and shoot with the flash at its E-TTL (or manual) exposure setting. If that doesn’t work for you, try the reverse—expose for the background and cut the strobe power by 1/8th-1/2. You’ll get a brightly colored foreground against a beautiful blue (or green, depending on where you’re diving) background.

Underwater black and white images can be as beautiful as their color counterparts but it’s always best to convert them to black and white after the fact. You’ll still have the color image and you have more control over the monochrome effect in post-processing.

To see what’s possible with underwater photography, look online and through magazines to see other photographers’ work. Most importantly, get in the water and have fun! With practice, you’ll soon be capturing consistently beautiful images .

 

Underwater photography, where noted, by Brad Sheard: www.bradsheard.com

The CDLC contributors are compensated spokespersons and actual users of the Canon products that they promote.

All images are copyright Dennis Sabo, Brad Sheard

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