Below is some technical details about camera magapixels. This could perhaps help in choosing a camera.
I was told by a professional photographer, that the lens is more important than the pixel count. Why? Most people don't need more than 6 MP. Our DSLR camera is over 10 MP, but if I'm not shooting RAW, I set it to the 6 MP setting (as this photographer recomended).
Editor Note 2018: While this was true in 2012, it is no longer the case. I now shoot at the highest resolution available. Hard drive and memory card storage is now inexpensive. If I absolutely need to squeeze more photos on a card, I do have the option to use a lower resolution but usually this is not a concern. From a web perspective things get interesting. JPEG compression is very lossy but images look better to the eye when they are scaled by the browser at higher compression. Let's create a hypothetical example to explain that point:
- A web design allows a photo that is 400x600px.
- Our 400x600px at 50% compression is 100KB.
- Instead, we can use a 800x1200px image at 25% compression. This also weighs 100KB. When it is displayed at 400x600 the browser scales it. This image looks better to the eye.
Here, more pixels comes in handy.
One reason is because the lens is how the camera "sees" light, while the camera's sensor is what records that info. If the lens makes the image look like puke, the Megapixels won't make a difference- you'll just be able to print larger than 8 by 10. Also, camera manufacturers sometimes cram too many pixels on a small camera sensor, and what you get is a lot of artifacts. MP is just a spec. More doesn't equal better. Also, in low light where enough light cannot get through the lens, extra pixels are "dead" and add to the noise.
Todays professional camcorders have 3 MP sensors. Some CCD camcorders have three sensors: one for each primary color of light: RGB.
HD video (1080 by 1920) is actually less than 3 MP. Some digital video cameras shoot 4K (4 times res of 1080p), such as the $30,000 RED used for Harry Potter. Also HD video is wider than photos. From Geometry, we know the square to have the most area with a set perimeter. Thus, not as many MP as still cameras.
(Compare a 199" x 1" box to a 100" x100" box. Same perimeter, very different area)