BetterPhoto Q&A
Category: New Answers

Mega Pixels

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August 18, 2007

In general, the answer is "not necessarily" - image quality depends not only on the number of pixels but also on the size of each individual pixel (wich translates into the size of the enire imaging chip). Let me explain...

When the individual photosites that make up the picture elements ("pixels") get too small, they can more easily read photons of heat given off by the electronics themselves (the sites only "see" photos, they don't see specific colors - each site has a color filter above it to handle that). So a sensor with 'too many' photosites ends up giving a noisier image file, all else being equal, than a same-size chip with fewer pixels.

Point & Shoot cameras have smaller CCDs than DSLRs, and by most accounts anything over 7 Megapixels is not worth it - there is too much noise in th eimage taken. DSLR chips are larger (they vary in size), so a 10MP DSLR will give a much better image than a 10MP P&S (again, all else being equal). For DSLRs today, even the "full frame" (a ridiculous term) Canons with 16+MP give excellent results.

Of course, as the technologies improve, the rules will change, but for now more does not necessarily equal better.

Also remember that a 10MP chip does not have twice the resolution of a 5MP chip - you have to double the number of sensors in both directions to double resolution, so to get 2X the resolution of a 5MP chip reqiures a 20MP chip.

Frankly, lens quality and technique have much to do with better quality - but speaking strictly about the chips, the "more is better" concept just ain't necessarily so.

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August 18, 2007

~Heather

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August 18, 2007