Digital Camera Master

Even though the camera field is evolving all the time, the basics really don’t change. Starting from this post, I will cover the most important elements to consider when shopping for a camera.

1. RESOLUTION
First and foremost, figure out how much resolution you need. This should be the first decision you make, because it determines what cameras you will be evaluating. Use the following info to decide what megapixel range you need:

Megapixels - Print Size
Sub-megapixel (VGA) –> Onscreen only (Web, email)
1 megapixel –> 3 × 5-inch prints
2 megapixel –> 5 × 7-inch prints
3 megapixel –> 8 × 10-inch prints
6 megapixel –> 13 × 19-inch prints, prints from small crop areas of the original image

Remember that even if you choose a 6-megapixel camera, you can set it to capture lowerresolution images—even a mere 640 × 480 pixels—making your camera quite versatile. Or you can capture a high-resolution image and reduce its size on the PC in an image-editing program.

The higher the resolution, the fewer pictures you can store at a given time, so there is a bit of a trade-off. If you buy a camera with too little resolution, though, you can’t ever add information to a picture, and trying to “blow it up” to print beyond its ideal size will generate a pixely, grainy mess.

2. OPTICS

It is a camera, after all—not a computer. Don’t forget to weigh the optics carefully. Your camera’s optics should be made of glass, not plastic, and multiple “elements” help keep everything in sharp focus through the camera’s entire zoom range.

Working with Basic Lenses
Also consider what kind of pictures you want to take. A fairly wide-angle lens is good for landscapes, indoor shots, and general-purpose photography. If you want to take portraits or wildlife shots, a longer reach is important. But take a look at the specs for a digital camera—what the heck is a 9.3mm lens? Is that wide angle? Who knows? That’s why most digital cameras also advertise their focal length in “35mm equivalents”—in other words, if this digital camera were a 35mm camera, its 9.3mm lens would give you the same picture as a 50mm camera, for instance.

Making sense of all this can be a pain. Worse, there’s no one formula you can use to convert digital camera focal lengths into 35mm equivalents. That’s because the focal length of a camera lens is based on the size of the film, which in the case of a digital camera is the CCD chip. CCDs vary in size, and there’s no industry-wide consensus on standardizing the size of the CCD in all cameras. So, your best bet is to check out the equivalency figures on the camera box or on the manufacturer’s Web site. I’ve also concocted a formula you can use in a pinch to convert digital camera focal lengths to their 35mm equivalents. Since CCD sizes vary, this is only an approximation. In the following formula, AFL is the actual focal length of the digital camera’s lens, usually a small number like 5mm or 10mm:

35mm equivalent focal length = AFL / .19

So if the camera has a 6.5mm lens, for instance, you can run it through this handy little equation and determine that it will work like a 35mm lens.

Choosing a Zoom
Of course, few digital cameras come with a fixed focal length lens. The focal length is a measure of how much the camera magnifies the image, and zoom lenses let you zoom in and out of a scene for the perfect composition. In general, the greater the zoom, the better. You’ll commonly see 2X, 3X, and perhaps even 5X zooms on digital cameras. With some simple finger pressure, you can use your camera to go from a normal or wide-angle view to telephoto.

Beware, though, of a camera’s digital zoom. While optical zooms move the lenses around to actually magnify the image, a digital zoom simply grabs a block of pixels in the middle of the scene and processes them to make the image look enlarged. Since the result is pixely, I suggest you ignore digital zoom ratings when evaluating a camera and just look at the optical zoom ratings.

3. MEMORY

The more memory your camera holds, the more pictures you can take. It sounds simple, but don’t forget that cameras come with all different kinds of memory solutions. In general, I’d say it doesn’t matter a lot whether your camera uses Compact Flash, SmartMedia, Memory Stick, or Secure Digital memory—the only things to consider are cost and capacity:

• Capacity
  If you only want to carry a single memory card on a long trip and store a huge number of images, a CompactFlash digital camera is your best choice. You can get CompactFlash cards in capacities as high as 1GB (that’s about a thousand 2-megapixel images). Most of the other memory formats top out around 128MB or 256MB. Of course, you can also buy several memory cards and carry spares.
• Cost
  The four memory card formats play a lot of leapfrog when it comes to price, so you might want to shop around for memory cards before you commit to a specific camera. But the two newest memory formats—Secure Digital and Memory Stick—typically cost a little more than CompactFlash and SmartMedia.