Digital cameras will be at the top of many holiday wish lists this year. And photo buffs everywhere want the ultimate camera: an SLR. But before you buy, research carefully.

SLR (single-lens reflex) cameras provide advanced controls. Shutter speed and aperture can be adjusted. And that's just the beginning.

Look through the viewfinder, and you see exactly what the camera will capture. A mirror inside the camera flips up when you press the shutter release. You won't get the dreaded shutter lag that plagues so many point-and-shoot models.

Some digital SLRs have fixed lenses. But I'd put my money into a camera that allows lens changes. And don't be fooled by SLR-style cameras. You want the real deal.

People tend to judge digital cameras by the number of megapixels, but that doesn't necessarily correlate to picture quality.

Megapixels refer to the size of image a camera will capture. The more megapixels, the more you can enlarge your pictures. So for large prints, you need a lot of megapixels.

Many consumer SLRs fall into the 6- to 8-megapixel range. But additional megapixels offer you more flexibility in printing. So, if you find a camera with more megapixels at a good price, go for it.

At the high end, SLRs take photos at eight frames per second. The low end is about 2 fps. You'll be able to shoot more continuous shots with a higher frame rate.

The more types of light metering, the better. Most offer center-weighted and spot metering.

Mode settings are common on point-and-shoot cameras. They are pre-programmed settings in the camera for situations involving a variety of lighting and movement. Most photo buffs want to work with settings, but sometimes they just want to take photos without a fuss. So look for a camera with shooting modes.

The ability to store custom settings also is nice. Having favorite settings at hand saves a lot of fiddling.

The camera should be able to capture images in JPEG and TIFF formats. The ability to capture RAW images is a bonus. RAW images are minimally processed, allowing more changes to them on the computer. They're smaller than TIFFs, without the data loss of JPEGs. The latter format allows for a high degree of image file compression, which accounts for its small file sizes.