Monday, March 26, 2007
Choosing The Right Digital Camera For You
How to narrow the multitude of options? Consider your photography habits and the features you really need
At the other end of the aperture range, few compact-camera lenses stop down beyond ƒ/8. Why? Diffraction. When apertures become very small, light tends to bend around the aperture edge, causing a loss of image sharpness. A 7.4mm lens set at ƒ/22 has an aperture diameter of 0.34mm—about 1⁄74 of an inch—lots of diffraction. At ƒ/8, the 7.4mm lens has an aperture diameter of 0.93mm—nearly three times as large, with much less diffraction. Due to the very short focal lengths of compact digital camera lenses, depth of field is very good, even at ƒ/8, so there's seldom a need for ƒ/22 anyway.
Size And Shape. A pocket camera obviously should fit in one's pocket, and smaller, lighter cameras are easier to carry around than larger, heavier ones. But smaller cameras can mean tinier controls that are harder to operate. When considering camera purchases, try holding the cameras and making settings to see how easy or difficult it is. How does the camera feel in shooting position and in carrying position?
Power Sources. Digital cameras can be powered by AA batteries, proprietary rechargeable batteries and some by AC power via an adapter (handy for indoor/studio work).
AA alkaline batteries are available just about anywhere but don't last long in digital-camera use. I'd go with a set of AA lithium batteries—they'll last a lot longer, have excellent shelf life and perform well in cold weather. There are also rechargeable AA batteries, a good option (don't try to recharge conventional nonrechargeable alkaline batteries).
Some rechargeable batteries hold a charge well, others don't. If you use rechargeable batteries, it's best to charge them the night before you go on a shoot. I'd also recommend having at least one spare battery set on hand (I have four spare batteries for my D-SLR), ready to go. If the battery in the camera dies and you don't have a spare, you're done shooting. Carrying the spare set in a warm pocket during cold weather will keep it ready to go.
Pixel Count. Ever since the first "megapixel" camera was produced, "megapixels" has been a key marketing item. A one-megapixel image is composed of 1,000,000 picture elements, or pixels.
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