100% crop?

bionicsherpa

bionicsherpa

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532
Name
Ken
Edit My Images
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This is probably an idiotic question but can someone tell me what is meant by the term "100% crop". I've seen it lots of times on this forum but, to me, a pictuture with 100% crop isn't cropped at all as you have 100% of the image, just as a 50% crop would be a half sized image. Alternatively, if I take it as meaning that you crop 100% of the image then you have nothing left, so it can't mean that either.

My understanding is clearly not right so please could someone put me straight on this?

Many thanks.
 
I suppose the simplest (?) way to explain it is that after an image has been cropped the pixels are still 1:1 and have not been resampled to a different resolution.

It's the equivalent of cutting a piece of a magazine out with scisssors - the cut piece of the magazine would be a 100% crop. If you photocopied that piece of the cut magazine and made it larger or smaller than it's real size then the photocopy would no longer be a 100% crop.
 
It is a crop of a image that is shown at 100% of the original uncropped image size. so a crop of 10cms by 10cms off of a 100cm by 100cm image is posted at 10cms by 10cms if that make sense.
 
I think what it means is 100% is classed as 1:1 ratio of the pixels, opposed to the compression and resolutions they appear on the screen

For example an image taken at say 2000x1000 pixels would mean you need a large monitor to view them on at full size (as the computer reduces the size of the image to fit the screen.

So if you view 1:1 it will zoom in so the pixels are viewed at their life size on the screen
 
Open the photo in Photoshop or other editing software, zoom in to 100% view and crop the image (make sure that the crop tool has no values in its settings as this may resample the image).

This is now a 100% crop. 1:1 ratio
 
The way I understand it is showing what the photo looks like at its original size. If I view a photo from my 40D on my 19" screen I am obviously viewing a smaller version of the actual image, as my screen is set to 1280x1024 pixels and the photo is 4000x2500 (ish) therefore to see one pixel of the photo at the size of 1 pixel on my screen I need to view the photo at 100%. I would do this in Lightroom by clicking on the image, which automatically zooms into a 100% view, or in photoshop I would go to the 'View' menu and click on 'Actual Pixels'.

I only ever use this for checking sharpness, as the smaller the image the sharper is can seem, so looking at 100% gives you an accurate representation. The crop bit of the term would then come into play if I wanted to show someone else this 100% view. I would crop the image to the size I can see on screen whilst at 100%.



EDIT - Or as most said above much more simply :)
 
Thanks for your explanations. Let me see if I have understood.

The maximum size permitted on this forum is 800pixels on the longest edge. If I want to post a 100% crop of one of my pictures I should select a portion of the frame with 800 pixels longest length and crop to that without resizing. As my D700 takes an image with longest side 4256pixels I will be showing just less than a fifth of the width of the frame at 100% crop.
 
In it's simplest form 100% crop is just cropping with NO resize.
 
That's my understanding now Ken. Thanks for asking the question, and thanks for all the answers, as it was something that always confused me.
 
bionicsherpa said:
Thanks for your explanations. Let me see if I have understood.

The maximum size permitted on this forum is 800pixels on the longest edge. If I want to post a 100% crop of one of my pictures I should select a portion of the frame with 800 pixels longest length and crop to that without resizing..
Click to expand...

Bingo! That's exactly what I do. :thumbs:
 
Well, that's very interesting, thanks all.

I've learned something today.

However if I crop a picture 100%, say 800 x 600, there probably isn't much of interest in it.:thinking:

How do I get over that :thinking:

Or am I reading it wrong :thinking:
 
Dave in Wales said:
Well, that's very interesting, thanks all.

I've learned something today.

However if I crop a picture 100%, say 800 x 600, there probably isn't much of interest in it.:thinking:

How do I get over that :thinking:

Or am I reading it wrong :thinking:
Click to expand...

Well 100% crops aren't normally, if ever, done for aesthetic reasons - they're usually done to show image quality at the pixel level (full file size or 1:1) on a forum where image size is restricted.
 
You wouldn't do a 100% crop for your final image. As CT says, 100% crops are usually done to show what the resolution of a full sized image looks like, without posting the complete image. This is because there are very few foums that will allow you to post an image that measures quite a few thousand pixels along it's longest edge. To avoid trying to post the complete image, you simply take a small sample from it i.e. a 100% crop.
 
thank you...i never knew what was meant by 100% crop and now i do :thumbs:
 
I've seen this term on the forum before and to be honest I've never given it much thought - so I've also learned something new today. Thanks to those that explained it :thumbs:
 
CT said:
they're usually done to show image quality at the pixel level
Click to expand...

Exactly. Just used to demonstrate flaws (or a lack thereof) in sensors & lenses (softness, chromatic aberrations, noise "grain", etc).

You'd never really use a 100% crop as a final image on screen.
 
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