Addendum
Megapixels
While there are valid points brought up about not giving too much weight to the number of megapixels a camera might feature it's important to consider three very important factors.
- The camera. Not every camera is created equal -- a ten megapixel shot from my Casio EXLIM 1080 and a ten megapixel shot from my Canon Rebel XTi yield two totally different results (even ignoring crop). Why? Because the physical sensor on the RebelXTi is significantly bigger than the one on the Casio -- a bigger sensor results in cleaner prints (i.e. less noise). Even the ten megapixel shot from the Nikon D80 will be a bit different (as it has a larger sensor than the Rebel XTi)
- The application. Sure a 3MP camera might be ok for 8x10s (I would disagree though) -- if you're shooting pictures for your 30" LCD -- which is 4.1MP, that won't cut it. While most of us dont have 30" LCDs, if you're main focus doesnt span the entire image (which, in the case of non-landscape photography, it usually is), the important parts of a the image wont be big enough to be displayed on 22" or 24" LCDs (which are much more prevalent)
- Value. At the end of the day it comes down to value -- $200 five years ago might have netted you a 3MP camera -- now it net's you a 10MP one -- with more features. Realistically, the consumer market starts at 6MP
SLR-Specific
With a SLR camera, the emphasis is not on the camera body itself so much as the lens, the lighting and the expertise of the photographer. Many times, people transitioning from computer-tinkering to camera-tinkering get too caught up in the "gear" rather than the "art".
Lenses
Get the best lens that you can afford for the task at hand! A better lens will make the different between a blurry/dark shot and a crisp clear one. Some points to consider:
- SPEED. Generally, the faster the lens - the better. Lens "speed" is measured using a weird notation "f/#" where # is a number like 2.8, 4.6, 7.2 etc/ The lower the #, the faster the lens -- think of it as latency. Some lenses have two numbers (i.e. f4-f5.6) while others have just one (i.e. f/2.8). Lenses with just one number are described as being "prime" -- it has that speed regardless of whatever other settings the camera has been set to (generally, if you zoom in, your "#" will go up -- meaning, if you zoom in, your lens is going to be a bit slower). This may or may not affect you depending on what type of stuff you are shooting. An extension on that -- you may not even need a fast lens at all: most of the nighttime photography i do is done at f/22 anyways!
- Stabilization. Some lenses have a built in mechanism for compensating for our subtle gyration/motion as we take a picture. Different companies call it different things (Canon: IS, Nikon: VR, Tamron: VC etc). They all do the same thing really. Image stabilization is really neat if you're trying to take pictures and dont have a tripod handy -- but it may not be for you depending on what you're taking pictures of: if you're taking pictures of outdoor weddings or picnics or activities in bright sunny environments, usually you're shooting so fast it wont matter. if you have a tripod that really reduces the need for a stabilized lens. Another factor to consider is if the camera body itself has a built in stabilizer. The very popular Sony Alpha A100 has inbody stabilizer so any lens can be popped in and the results will all be stabilized!
- Focusing mechanism. I think it was originally pioneered by Canon, a focusing mechanism called USM (ultrasonic motor) but nowadays the technology is present on other brands too (i.e., Nikon's SWM, silent wavemoyot). Essentially a lens with USM 'technology' will autofocus faster and quieter than one without. Whether or not you need this is up to your specific needs -- personally I know a few shots of mine would not have happened without it (granted they were taken at 130km/hr of stationary targets)
- Type of lens. This important! You need to assess what type of photography you want to do -- wide landscapes, portraits, macro, zooms and buy the appropriate lens. For most people a 17-85 should sufficient to handle what they might need as a beginner.
Filters
While fanatics and pros will argue about UV filters affecting image quality -- if you're reading this, odds are you're gonna want to have a UV filter on your lens. While it helps to cut out haze from your image, it's major function is to protect the lens -- if you scratch it, you only have to replace a $50 peice of hardware rather than, say a $2000 lens.
There are other filters out there, one of the more popular ones is a polarizer. It's same idea as polarized sunglasses -- and its this filter that makes clouds and sky have some serious contrast and "punch".
There are zillions of filters out there and whether or not they are for you will depend on what you need to do. ND Grad filters (neutral density gradient) essentially reduce the amount of light entering the sensor which can be useful depending on what you want.
Other notes and suggestions- ISO. No matter what, the lower the ISO number, the "cleaner" the picture. You'll want to shoot in as low an ISO mode as possible -- sometimes you cant (i.e. if you want to take pictures of fish at an aquarium -- which are usually very dim). Picking a lower ISO number means you'll need to either have a lower F/# and/or a slower shutter speed -- which isnt possible: the lens limits how low of a f/# you can go and the scene limits how slow you can shoot (ever try shooting tropical fish? the buggers dont sit still)
- Aperture This is the f/# thing. If you want the full version, have a read at this it's very well written. If you want the simple version, the lower the #, the 'faster' the lens (see above about faster lenses). A faster lens lets you shoot with less light and/or faster objects.
- Shutter speed This is litterally the amount of time the sensor is exposed to light. The total amount of light to touch the sensor is determined by the aperture (how big the hole is) and the shutter speed (how long light has to go through that hole). In a brighter environment, you'll want to increase the shutter speed. In darker scenes you'll need lower (aka "slower") shutter speeds which may mean u need a tripod. You can artificially add more light to the scene -- that's what flash is
- Metering mode This one is a bit complicated to simplify: it's the way that the sensor measures how bright a room is. Evaluative takes the scene as a whole and judges the whole scene for light intensity -- it's an average of the entire scene where ever spot is valued equally. Centre weighted does the same, but values the center area more. Spot metering measures the intensity just for a spot.