PC World's Digital Focus: Camera Tips and More

Here at my home office in the Rocky Mountains, summer is starting to drag on. I can tell because even dishwasher-safe plastics melt all over my desk if I leave them out at midday. In this kind of heat, the best place to be is underwater--no matter if your summer includes plans for Orlando, Belize, or just the local swimming hole.

While you're there, take a digital camera. Underwater photography isn't just for the Cousteau family anymore--I'm amazed, in fact, at just how popular aquatic cameras have become.

It's not hard to see why. The same things that make digital cameras popular up on the surface also make them great for taking snapshots of parrot fish, stingrays, snorkelers, and starfish, too. You can immediately review and delete pictures that didn't come out right, while you're still in the water--and that's important since you can't change rolls of film (or even memory cards) while everything is wet.

Intrigued? Great. Unfortunately, you can't take your digital camera into the water unprotected, and wrapping it in a ziplock bag isn't going to cut it, either. You'll need to invest in a watertight housing.

Several companies make waterproof housings for digital cameras. Because different cameras have different sizes and shapes, you'll need to look for a housing that fits your exact model camera. Ikelite is one of the biggest names in digital housings--they make models that encase well over three dozen cameras, from the Nikon CoolPix 995 to the Olympus D340R and a dozen different Sony Mavicas. (See our latest camera reviews.)

Both Ocean Brite and Light and Motion seem to specialize in Olympus digital camera housings--if you have a C2000 or C3000 series camera, these are the folks to see.

But for my money, the coolest underwater system out there is the Sony DSC P1 digital camera with Sony's Marine Pack housing. The DSC P1 is a bullet-shaped, palm-size digital camera that captures super-sharp 3-megapixel images. Even in its Marine Pack housing, the camera still fits snugly in your hand, making it a great choice for snapshots in the local pool, for snorkelers, and even for divers who want to travel light.

Taking pictures underwater is quite different from shooting snapshots on the surface. You'll want most of your pictures to be close-ups, so enable the macro setting on your camera (the universal symbol for macro mode on digital cameras is a tulip).

Why close-ups? If you get too far away, you'll get backscatter. Backscatter is the snow-like reflections that appear all over your picture because your strobe illuminated all the particles suspended in the water between you and the subject. You can reduce the effect of backscatter afterward by running a "noise reduction" filter on your picture in an image editing program such as Paint Shop Pro.

If you're planning to take pictures while snorkeling or swimming near the surface, the sun provides pretty much all the light you'll ever need. But what if you're taking pictures 30 or 60 feet underwater? That's when you should consider bringing some extra light with you. Here's the problem: Water filters out sunlight, but it does so in a sneaky way, starting at the red end of the spectrum and working its way to blue.

That's why underwater pics often have a bluish cast--at depth, the reds and yellows that make pictures look alive are long gone. Even with digital processing, it's hard to "add" those colors back in later--so you should attach an external strobe to your camera. Most companies that make underwater housings can help you choose a strobe for your camera.

If you've got some deep water pics that you took without a strobe, you can try to restore lost color through digital trickery, but the results aren't perfect. Here's what you can do: Open the picture in an image editing program such as Paint Shop Pro or Adobe Photoshop.

Now split the picture into three, one for each color (red, green, and blue)--in Paint Shop Pro, for instance, choose Colors, Split Channel from the menu. If you look at each of these three images, you'll see that the red channel is almost blank--there's very little color information in the red end of the spectrum. So throw this image away. Re-combine the three channels into a single picture again by choosing Colors, Combine Channels. But when you recombine them, tell the image editor to use the blue channel, which has a lot of color information, as the red part of the picture. You should see the picture pop back to life--it won't be a perfect recreation of the scene, but it'll look a lot better than it did before.

If you've got a digital camera, odds are good that you've got rechargeable batteries. Those little AA-sized NiMH batteries have one problem--they seem to run down way too quickly, and it can take hours to charge them back up again.

That's why the Rayovac 1-Hour Charger is so cool--it does exactly what it claims, topping off a set of four rechargeables in about an hour. In my experience, that's two to four times faster than most of the competition. When I'm traveling with a camera, sometimes an hour is about all the time I have in the hotel room between sightseeing excursions, so this is a real winner. By this time next year, I'd expect to see several one-hour chargers on the market. Right now, though, this is the only one around.

The Rayovac charger is no larger than most four-battery chargers, making it easy to fit in a travel bag or a camera case. It is also compatible with a soon-to-be-released optional car charging adapter, so you can charge on the go. The charger unit itself sells for $29.99.

My digital camera accepts CompactFlash cards. Does that mean Type I, Type II, or both? Can I put an IBM Microdrive in there too? --Tony Olsen

The CompactFlash format is a popular style of memory card for digital cameras. It comes in capacities ranging up to 512MB, meaning that you can shoot hundreds and hundreds of pictures without swapping memory cards--provided you're rich, that is, because those high-capacity cards are expensive. Though a 128MB card might cost just $130, a 500MB card can cost $500 or more.

Nonetheless, we're talking about computers, so it's not quite as simple as it seems. There are two kinds of Compact Flash cards--Type I and the slightly newer Type II. Type II cards are a bit thicker, designed to accommodate more silicon for higher capacities. Since Type II cards debuted, though, the technology has advanced, and most memory manufacturers have found they can pack the same memory in the thinner cards anyway.

Another wrinkle--IBM's Microdrive is a tiny hard disk that can pack as much as a gigabyte of storage space into a Type II casing. (For more on the Microdrive and other types of miniscule storage, see "Honey, I Shrunk the Bits!")

So, which format can your camera accept? All Compact Flash digital cameras will have no trouble with Type I cards. Check the user manual or call the manufacturer to see if Type II cards will physically fit in the slot--or just try to slide one in when you're in a store. You can't damage the camera; if it's a Type I slot, the card simply won't fit. As for Microdrives, even if it fits you're not out of the woods--these drives require more power than a lot of Compact Flash slots can deliver. Check with your camera manufacturer before you try using one.

Send your questions to dave@bydavejohnson.com.

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Swan Tracks by Dave Johnson

To kick things off, here's one of my personal favorites: a shot of swans wandering around the snow-covered ground in Utah. I took this picture last fall, when the first snow had fallen near Salt Lake City. I loved the lines the swan tracks made in the snow and captured a shot with the Olympus e-10, a 4-megapixel digital camera. The only change I made to the image on the PC was a little color correction; I found the white snow confused the metering system and the image was tinged slightly with green.