The world of digital underwater photography can be confusing and more than a little intimidating to the uninitiated. Practitioners seem to speak in code, using esoteric vocabulary and indecipherable acronyms--TIFFs, JPEGs, CCDs and megapixels. And if that's not baffling enough, there's also the problem of choosing from the hundreds of competing products that are available both at the high end and for point-and-shooters.

There is good news, however: The learning curve is a quick climb, and it's one that's well worth making. Your first step in underwater digital photography should be to examine your personal criteria.

Do you already have a digital camera?
If so, there is a good chance it can be housed. Ikelite offers more digital camera housings than anyone else. Some of the mainstream camera manufacturers offer their own housings as well, especially Canon, Sony and Olympus. Gates Underwater Products has some excellent housings for the Sony line, and Light & Motion has long supported Olympus and Nikon. Certain Nikon Coolpix cameras can be housed by Fantasea, Sea & Sea and others. With so many options--far too many to list here--a good reference for which housings fit which cameras is found at www.digideep.com. Click on your camera preference and the site will display housing options.

Which camera should you buy?
Assuming you haven't bought the camera yet, the choice can become even more confusing, as you have to consider options such as camera features, megapixel capacity, and of course, price. Starting with a clean slate presents other options as well. Sealife Reefmaster offers a clever camera and housing system optimized for underwater photography, complete with add-on optics for both wide-angle and macro. Sea & Sea likewise offers a camera and dedicated housing (DX-3000), as well as the Aquapix, an amphibious digital camera that doesn't require a housing.

If you don't already own a camera, look at housing options first. Truthfully, I'd be hard-pressed to tell you which of the dozens of competing viewfinder digitals offered by any of the camera manufacturers are better than the others. Most will be in the four- to five-megapixel range, offer good zoom range and built-in flash, and most will take stills and MPEG movies. These are really pretty amazing products that continue to drop in price and add features.

For great photos, consider investing in a sophisticated housing.

Which housing should you buy?
Now is the time for a bit of introspection. What do you want from your digital images? Will they be snapshots? If so, maybe a simple Plexiglas enclosure will do the job. You'll have only the camera's built-in flash, and the housing's flat port will create refraction and make the widest zoom less wide than it would be above water. Because the built-in flash is so near the lens, if there is any particulate matter in suspension, backscatter is inevitable. But the price should be very affordable (under $200), and if you know how to operate your camera topside, these housings will give access to all relevant controls and make underwater operation very simple. Let's take a look at the extensive line of housings from both Olympus and Canon.

Want to grow with your underwater digital imaging? More sophisticated housings will offer the ability to use external strobes (either by hard-wired sync cord, cordless slave or fiber-optic cord), the ability to add accessory wide-angle and macro lenses, as well as greater depth capability, and have enhanced ergonomic features. Consider the external strobe and accessory lens options as critical components in any advanced prosumer system.

Which strobe should you buy?
Of all the digital variables, strobe use seems to create the greatest conundrum. Digital viewfinder cameras determine automatic strobe values by reading a preflash so they know how much light to pump out during the "real" exposure. A conventional slave strobe will likely trigger due to the preflash, and not be recycled quickly enough for the real deal. Fortunately, strobe manufacturers have been quick to pick up on this problem and create diverse solutions. Ikelite, Inon and Sea & Sea are three strobe manufacturers that have been active in this area. Their solutions range from fiber-optic cables that read the in-camera flash and synchronize appropriately to remote slave sensors and strobe circuitry engineered to mimic the camera's preflash. Light & Motion has tackled the problem from a different angle and created circuitry in its housing's ROC controller to effectively deal with this problem. Engineers in all of these companies are making the use of accessory strobes much easier with point-and-shoot digital cameras. It's still a work in progress, but impressive advances have already been made.

Follow the Rules
Regardless of which system you choose to use under water, the rules of underwater photography remain inviolate.

Get close. > The density and color of seawater are enemies to quality underwater imaging.

Find clear water. > Of course this isn't always possible. But clear water is better for reducing backscatter, especially when using a camera's built-in flash.

Use interchangeable optics. > With a viewfinder digital, this will typically mean external optics that can be added while under water, but some housing manufacturers have created ports optimized for screw-mount lenses that must be installed before you get in the water.

Be creative in your use of strobe light. > Good color in underwater photography comes from the proper application of artificial light. Most of the best new digitally enabled strobes offer as many as 10 different power settings, so very subtle effects are possible with the turn of a knob.

Be aware of the importance of ambient light. > Blending strobe and ambient light effectively is critical in making the leap from only recording the moment to creating art. Easy access to the camera's shutter speeds and the strobe's power settings are absolutely necessary.

Capture subjects that are photographically worthy. > A bad photo is still a bad photo, whether it resides as silver halides or pixels. Digital imaging requires the same creative eye and brutal self-critique as does analog capture.