Print sizes vs resolution

[_dobbo_]

sorry if this has already been discussed here, i did a quick search but didn't turn anything up...

What's the accepted wisdom on print size vs resolution.

I've just had a bunch of 10x15 inch prints done from my 5MP Ixus 500. There's a tiny bit of pixellation showing but hardly any at all really, and I was expecting much more to be honest.

Price wise, I thought 7 prints at 10x15 for 19 quid was pretty good, and given the quality of it I'd have no concerns printing more this size. has anyone gone bigger?

[fatsteve]

I depends largely on how the image is resized. I tend to use PS to size the images prior to printing. For example if I want a 6x4 printing that I size the image in PS to 6x4 this, in theory means you have more control over the scaling (and the labs shouldn't need to resize the image).

Theres alot of debate over pixels vs inches/cm, but the general rule (that I've found from numerous photo sites) is scale at 300dpi.

On this basis, a 5mp image is 2560x1704 pixels, this equates to 8.5 x 5.7 inches before the image starts to pixalate.

My 300D is 6.3mp hence 3072x2048 hence 10x6.8 inches, but with a bit of work in PS, I've managed to scale up to Super A3 (19x13 inches) without any really noticble pixalation. However it involved a fair bit of fettling with PS.

Finally, another consideration with image quality / scaling is what ISO you are using. If your using a high ISO number (ie > 800), then the image has more noise to begin with, and this will be more visible the bigger you print the image (even 1:1)

Of course, I could be talking bs!

Hope this helps

Steve