Posted 02 September 2008 - 03:07 PM
As others have said, depends on the image. I've got a 20x30 image of a pygmy seahorse shot with the 10D that stands up to scrutiny even if your nose is on the glass. I printed tigershark shot by a friend on my HP Z3100 44" printer from her Bahamas shark dive with Jim Abernathy end from her D200 that's 36" wide, it looked so good that I printed another copy and it's now hanging in my office (signed by the photographer). Some hotshot NYC fashion photographer printed 8 foot tall portraits of kids shot with a 6MP camera. If you print on canvas, the texture of the medium will provide perceived detail, but if you print on glossy then you won't have as much leeway, it also depends if you're printing something with lots of detail like a coral reef or something with smooth textures like a person's face.
There are no hard and fast rules, viewing distance is a factor as well, everything doesn't have to be 300 dpi, if so then billboards wouldn't be possible as those are printed no in dots per inch, but dots per feet!
SLS Photography, when your images matter....
Aquatica, Amphibico, TLC, ULCS (Philippines), Stix, iTorch, FIT, Magic Filter Dealer
Philippine Dive Trip Specialist