Of course there are plenty of digital cameras that work with Mac's. Most middle to high end cameras already do (the cheapo $49 models most of the time don't). The real question is, what are the things you are looking at in a digital camera.The things to look for are interface, storage options, display, quality, and reviews.
Interface: Options are Serial, USB, and FireWire. Most of your older cameras come with Serial connections, most probably have a Mac DB9 serial adapter. Serial is mostly replaced nowadays. USB is currentlt the market favorite. USB is on roughly 90%* of shipping cameras. FireWire is the last option, and is the rarest and most expensive. Look for it on only the highest end models.
Storage Options: Options are Compact Flash and Built-In. Compact Flash is the more popular type out there, encompassing around 75%* of the current market. The reasons for this is because expansion is easy as changing the card (cards are available from 16-512MB). Few cameras have built-in storage, because it is trying to keep costs down overall. The lack of image space expansion is a major drawback, and is generally held for the low end models.
Display: Options are Rear LCD and Viewfinder. The Rear LCD is becoming the market dominant thing. Most decent cameras have a small LCD display on the back, designed so that you can hold the camera a little farther away from your face to see the image, and also view the image after taking it. Viewfinder is like the traditional 35mm cameras, and are generally found on the low end models.
Quality: Quality is a major factor in digital cameras. Digital cameras measure the image quality of it's cameras by megapixels. The more megapixels an image contains when taken, the higher the quality and less pixelated it is, and larger the file size is also. Some cameras are great in bright sunlight, but are washed out in darker rooms and the like. Which brings me to my final point...
Reviews: Read as many reviews on cameras. Most of the mid-class cameras have been reviewed by popular magazines (MacAddict, MacWorld, etc.), and show basic insight there. The reviews part is relevent and time you are going to purchase something, because of the "buyer-beware" atitude of many companies. Research is always the place to go when you are unsure.
Recommended cameras:
Low End:
ixla PhotoEasy
Built-In storage for 32 pictures (unknown picture quality)
USB interface, Viewfinder
$99
Mid-range:
Olympus D380
Compact Flash storage
USB interface, LCD viewscreen, 2.0 megapixels
$199
[I can't think of a high-end right of the top of my head]
Look around various makers of cameras for rought pricing, and feature lists. Olympus, Canon, HP, and Sony are your main mid-range makers.
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