Cropping AFFECTS your image quality !!!

[shojibake]

Will not affect the quality however you want to zoom and crop. 100% crop is best thought of as zoom 100% and crop a portion of the image for the purpose of examining picture quality.

 

[melcheong72]

Good thread, clear some doubts

 

[wong1979]

Hi eric, I think I know why you mean by degrading when cropping using photoshop. For my instance, it's CS2. By default, the crop tool comes with a resolution of 300 pixels per inch or cm. I just discovered just now that by clearing away the resolution detail, leaving it blank, and then setting the ratio aspect as 4:3 or 4000:3000, both the same thing. And you just select the area u need to crop. Whether at viewing 100%, it doesn't matter. Cos ultimately, when u zoom in ur cropped product, it will be the same size as what u see uncropped zoomed at 100%.

Another method is using the rectangular marquee tool and just select, then image-->crop no need to do anything but it seems that u can't set an aspect ratio for it.

 

[karnage]

as for what a 100% crop is... most of the pictures you see on the forum have been resized because at 100% it would be bigger than the screen and hard to view. so people resize the picture from say 3000x2000 to 600x400.

but if you want to have a good look at how noisy a camera is, or how much chromatic aberration you get from a certain lens, or just to compare equipment side by side, it's much easier to see the details when the image is 100%

so to do this on the web, people post 100% crops: they crop out small sections of the picture, and DON'T resize it. e.g. crop out a 600 pixel x 400 pixel section of a 3000x2000 picture, and post it.

I think Pai's explanation makes the most sense to me. Doesn't confuse me as much as the others. =)