Get the facts before you buy: 10 secrets of digital SLRs that you absolutely,
positively have to know now.
9) The Best Cooks Leave It RAW. But You Don't Have To.
The CCD or CMOS sensor in a digital camera doesn't produce a picture -- it produces a heap of dots and dashes. The processor in your camera sorts them into a file that can be recognized by a computer.
The least processed is the appropriately named RAW file, which is very close to the original pile of dots and dashes. RAW files need to be processed in software outside the camera before you can see them on your computer or print them. In practice this is no big deal; you simply open them in the camera maker's RAW converter software, which assembles the picture according to how you set the camera.
The real advantage of RAW comes if you intend to do "darkroom" work on your images. RAW captures nearly everything the camera sees, and so you can make all sorts of adjustments later -- like exposure, contrast, and color balance -- without degrading the image. It's especially useful for capturing photos that have a very wide exposure range between highlights and shadows.
Camera makers all use their own RAW format. The conversion software is almost always included with a DSLR purchase, although some manufacturers charge extra for premium software (e.g., Nikon Capture NX) that offers greater editing ability. Adobe is promoting its DNG (Digital Negative) format as a universal RAW format, but it hasn't caught on yet.
A disadvantage to RAW is that the files are big -- several times the size of the biggest JPEG, the most common type of image file. JPEGs save the image settings you used when you took the picture, but compress the file considerably. JPEGs save you memory space and are quick and easy to open. They give you less leeway for image correction later, though, and may provide less image quality, depending on your settings.
Many DSLRs offer simultaneous RAW + JPEG capture, a good idea for important shots. Yes, this will take a lot of memory, but the price of memory has come way down. You should buy at least two memory cards of at least 1 GB apiece -- remember that, unlike film, these can be cleared and reused. If you do a lot of traveling with your camera, a portable mass-storage device is a good idea, too.
Some DSLRs can also capture shots as TIFF files. Don't do this. Stick with RAW + JPEG.
Pop Photo Tip: For quick and casual shots, JPEGs are just fine, but if you're a real enthusiast, RAW is worth using. Learning conversion software is neither brain surgery nor rocket science. And always archive your RAW files -- that's what the CD/DVD burner on your computer is for.
10) Your DSLR Viewfinder Is Better Than Any LCD, Ever.
In some ways, a reflex viewfinder improves on the real-world view. By showing you the scene through the lens that's taking the picture, it reveals the exact perspective you'll get in the photo. By focusing this image on a ground-glass screen, it reduces it to two dimensions, giving you an accurate sense of the final picture and letting you check the depth of field.
The other great thing about optical TTL viewing is that it's continuous, aside from a negligible blink when the mirror flips up and down. While LCDs and electronic viewfinders (EVFs) have improved at redraw, they're still jumpy as you try to follow live action or shoot in bursts.
Better SLRs use a solid glass prism (pentaprism) to direct the light path to the eyepiece. Some SLRs use a hollow box lined with mirrors (pentamirror), which saves some weight and bulk as well as cost. Although pentamirrors used to be dimmer than pentaprisms, this is no longer a hard rule. However, viewfinder readouts (such as shutter speed and aperture) outside the picture frame may be harder to read with a pentamirror.
Magnification refers to the size of the picture you see when you look through the finder using a 50mm lens. It's expressed as a factor -- 1X means the picture appears at the same size as it does with your naked eye. (Magnification can exceed that factor.) Low-magnification finders have a tunnel-vision effect: It looks like the frame is some distance from your eye. High magnification is desirable, although it may make it harder for eyeglass wearers to see to the very edges of the frame.
The proportion of the image in the viewfinder that actually ends up in the picture, expressed as a percentage, is known as accuracy. The very best you can do is 100 percent. DSLRs have uniformly very high accuracy these days. Note that SLR viewfinders can, and often do, show parallax -- the finder image may be slightly shifted from the recorded image.
Pop Photo Tip: We rate the magnification and accuracy of DSLR viewfinders in our Certified Lab Tests, so consider the results when shopping. And look for clear, bright readouts in the finder as well.