Cropping Photos from 30D = how big can you go really?

Yeah,

photos shot as RAW from a 30D; how big can I crop these w/o losing resolution?

Like can I crop it 16x20? I notice that when I bring the file into photoshop, it says its like 9 x 11 or something along those lines, so if I crop to 16x20, would I then be interpolating the image?

Any help would be appreciated!

Every crop loses resolution. If you take an 8 megapixel file and crop out 25% of its pixels, you're left with a 6 megapixel file. You can print as large as you want, there's no constraint on it, but just be aware that with crops you not only lose pixels but you also increase the enlargement factor of any print -- and enlargement factor is the single most important determinant of print sharpness once an image has been captured (far more important than pixel density).

When you say crop it to 9x11 or 16x20, all you're talking about on the computer is an aspect ratio. In this regard 9x11 is equal to 18x22 and 27x33, and 16x20 is equal to 4x5 and 800x1000. Crop to whatever aspect ratio works for you.

The interpolation issue comes in when you decide on the physical size of your print -- because at that point you might need to add pixels via interpolation to have a sufficient pixel density in print.

A buddy of mine who is a pro shooter in Germany uses has used Canon digital since the 10D. That was a 6 megapixels sensor with a 1.6 crop factor. Most of his shooting is for "Outdoor Advertising" (billboards). Those 10D shots were regularly blown up to 5 x 8 meters - about 15 by 25 feet. Seeing that that was a 10D, the 30D would be even better.

The reality is this: you can print as big as you want.

Rad

Radtech1 wrote in post #3194032
The reality is this: you can print as big as you want.

You can print as big as you want, yes, but if you go big you may not be satisfied with the sharpness and detail in the results.

I've printed up to 11x14 from my 300D, i.e. the same resolution as the 10D, and even at 8x10 I'm not entirely satisfied with the sharpness and detail of the images -- but I also shoot MF and LF and my expectations of the detail in an 8x10 print are quite a bit different than they would be if I did not routinely use these formats.

Also, billboards are viewed from great distances. Poster size prints are viewed up close. At every gallery exhibition I've attended, people look at 30x40, 24x30, etc prints from within a 1 foot viewing distance. At one Ansel Adams exhibit I saw, people were looking at this 3-panel ~8x10 foot screen from less than a foot away. So printing a billboard is actually easier than printing a poster, because you can get away with it.