The shocking news of the day -- Nokia is making a phone with a 41MP camera -- is shocking for all the wrong reasons. It may shoot higher-res than most DSLRs, but that won't help you at all. Why? After a certain point, megapixels don't matter.
Pencils down, everyone!
A megapixel is one million pixels, referring to the number of pixels a camera's sensor can capture when it's exposed to light. In plain thinking, the higher the better -- more pixels generally mean more picture detail. So wouldn't 41 megapixels be a hell of a lot better than the 36 Nikon's juggernaut D800 packs? The phone must be even better than the DSLR, or at least close, right?
Not at all. Not even close. Not all pixels are created equally.
A phone, obviously, is much smaller than a camera -- especially a big pro shooter like a Nikon or Canon DSLR. This means that phones can only accomodate a dramatically smaller sensor -- the light-sucking plate that takes photons and converts them into pixels. A small sensor means that pixels themselves have to be smaller if there are going to be a lot of them, and small pixels suck. Like a crowded fraternity basement, a small, high-megapixel phone sensor creates images mired by discolouration and noise. They may be large images, in terms of the JPEG you view on your screen, but they're not precise, beautiful images.
That's why a big sensor and a nice lens -- also lacking in a phone -- are what you should focus on. That's what yields beautiful shots in low light settings, accurate colours and broad dynamic range. It's these factors, not megapixelage junk-measuring contests, that you should be concerned about. A large sensor, like those found in actual cameras (and DSLRs in particular) accommodates spacious, luxurious pixels that have room to stretch out and pick up more light. This means a more accurate image -- even if the megapixel number is far lower.
But why, then, do the top-end DSLRs pack massive pixel counts? Because pro photographers are using them for pro settings: magazines, billboards, television. But the naked eye can't tell the difference between 8MP and 100MP if you're printing on anything smaller than legal pad-size, or posting to your Facebook wall, or sending as an email attachment.
This shouldn't be hard to put together. A small smartphone with 41 megapixels sounds impressive, sure, and it may well take a good picture. But remember that those megapixels, like the ones in countless beefed-up point-and-shoots, don't have room to breathe. And even if they did, your eyeballs wouldn't be able to tell the difference unless you're printing up posters on the regular. The result, short of some engineering spectacularity, will be largely diminishing returns.