How to do 100% crop

I need to do a 100% crop of a photo to view the quality and everything of a lens and i dont know how to do it.

Could someone help me please?

Can't help, but I would be very interested too.

Open the image in your editing program of preference.

Zoom in to the image until it is sized at full size, or 100%. In all probability it will be too big at this stage to completely fit on your screen.

If you only want to view it, that's all you need to do. If you want to be able to post a 100% crop so that others may comment, take your crop tool, and cut out the piece you wish to post.

What you are effectively doing is giving yourself an image that can be posted without breaking any size rules on the forum, but the cropped portion you do post will be a small piece of the original image, but at 100% size.

If you need more explanations about 100% crop and have 10 minutes to kill, click below.

https://photography-on-the.net/forum/showthre​ad.php?t=801929

Sorarse wrote in post #9291436
If you only want to view it, that's all you need to do. If you want to be able to post a 100% crop so that others may comment, take your crop tool, and cut out the piece you wish to post.

I do that and in photoshop CS4 the 100% crop is 1365 x 890 and thats to big to put like in a forum i have the canon XSI and originial file size was 4272 x 2848.

have an idea how to do it at a smaller size without resizing ( i heard weren't supposed to do that)

Then you are making your crop too big. Just crop a smaller portion. May need to adjust the settings of your cropping tool to achieve that.

Boo-Man wrote in post #9291480
I do that and in photoshop CS4 the 100% crop is 1365 x 890 and thats to big to put like in a forum i have the canon XSI and originial file size was 4272 x 2848.

have an idea how to do it at a smaller size without resizing ( i heard weren't supposed to do that)

Just crop a slightly smaller section. You can set a specifically sized crop with photosochop, so set your crop to like 800x800 and it will end up being a 100% crop.

tkbslc wrote in post #9291546
Just crop a slightly smaller section. You can set a specifically sized crop with photoshop, so set your crop to like 800x800 and it will end up being a 100% crop.

Yea i think i got it, thanks!!!! I did some research on google on the side

Make sure that's "800 px" and not "800 in" or "800 cm" in the size boxes.

https://photography-on-the.net/forum/showthre​ad.php?t=497533

Thanks Duncan!