The 40D has a resolution of 3,888 x 2,592, which (theoretically, and if my math is correct) at 300 ppi gives you a maximum print size of 12.96 x 8.64 without any kind of resampling. Dropping the ppi down to 240 would give you a 16.2 x 10.8 print and still give you an acceptable print. BUT, you can resample your image in Photoshop, or use a program like Genuine Fractals to give you a larger print. If resampling in Photoshop, it's best to do so in small increments, like increasing by 10% until you reach your desired size. I've made nice 20x30" prints for walls from my 8.2 mpixel 20D or 30D this way, which leads into another factor: viewing distance. Most people don't look at a large print from the same distance they would look at a 4x6" print. Some say take a diagonal measurement of the photo and multiply that by 1 to 1.5 to give you an acceptable viewing distance. Hope that makes sense and I'm not too far off, it's early and I haven't had my coffee yet. :-/
Luminous Landscape has a nice tutorial on resolution, and  Konador put a great video tutorial together with lots of good tips in there. |
