Cropping

I just saw a post where the photographer said the photo he presented here was nearly a 100% crop. How do you define/determine the percentage of crop? If my original image dimension is 3000x2000 (6MP) what would be half? Any dimension that totals 3MP?

My understanding is that a "100% crop" just means that the image presented is pixel for pixel from the original image.

mbellot wrote in post #19473863
My understanding is that a "100% crop" just means that the image presented is pixel for pixel from the original image.

Yep that's correct. Every original pixel from the original is being shown with no resizing etc.

chuckmiller wrote in post #19473831
I just saw a post where the photographer said the photo he presented here was nearly a 100% crop. How do you define/determine the percentage of crop? If my original image dimension is 3000x2000 (6MP) what would be half? Any dimension that totals 3MP?

All that means is that the person viewed their image at 100% with whatever tool they use, then they cropped a visible section on the screen, then saved that resulting new file to something and posted it. They didn't resize or resample anything.

It is then up to those that view that new result on how they make sure it is 100% file pixel to screen pixel. On large resolution monitors, it just means probably that people are seeing a very small image, for those with lower resolutions, that image will appear larger.

mbellot wrote in post #19473863
My understanding is that a "100% crop" just means that the image presented is pixel for pixel from the original image.

That's counterintuitive. I suppose the convention is well established, but cropping 100% would mean reducing the image by 100%, that is, deleting the image.

I think the term just sprang into being from a different direction. It's a cropped portion of a 100% (pixel to pixel) view. Usually 100% views are used for discussing sharpness or other aspects of image quality, so the entire image isn't relevant and a small portion will be displayed for the discussion.

100% crop = "100%, cropped." Yeah, if you come from thinking about cropping off some percentage or cropping down to some percentage, it's not going to work for you.

Typically that means 'view at 100%'...one pixel in photo = one pixel on monitor...and then crop to that view so that anyone else viewing the remaining image is seeing one pixel on their monitor for each pixel in the image

So, cropping an image is no longer a straight forward black and white subject, like I think it probably was with printed photos and before household computer monitors.

If you are looking for ways to be confused you can add in that APS-C sensors are called crops.

chuckmiller wrote in post #19473914
So, cropping an image is no longer a straight forward black and white subject, like I think it probably was with printed photos and before household computer monitors.

I see no reply which does not agree with ALL of the other replies! There is one reply which does explain how 'cropping 100%' could mean something different, 'trimming off everyything', from the otherwise agreement

A '50% crop' would mean that every other pixel of the image (in each direction) is not viewed by the software...your 3000x2000 image would be '50%' if you were trying to view the entire image area on a computer monitor that had only 1500 x 1000 pixels...like on a small 13" entry-level laptop

I grew up on cropping ratio from aerial photography.
A 25% crop was a ¼ of the original cover at full, original resolution
No such thing as 100% crop there.

I found it weird when starting contributing to photography forums and the crop was mentioned as 100%

AntonLargiader wrote in post #19473891
I think the term just sprang into being from a different direction. It's a cropped portion of a 100% (pixel to pixel) view. Usually 100% views are used for discussing sharpness or other aspects of image quality, so the entire image isn't relevant and a small portion will be displayed for the discussion.

100% crop = "100%, cropped." Yeah, if you come from thinking about cropping off some percentage or cropping down to some percentage, it's not going to work for you.

Here's one place to come from. I used to prepare copy (excuse me, text) and images for offset printing. To exclude ambiguity, when directing the printer to resize original art that you want smaller, you always write "Shoot at 75%," for example, never "Reduce by 25%." Since cropping means taking off part of an image, I should think "25% crop" would mean reducing an image by one quarter, but it doesn't if usage is the same for 100% and 25%.

I remember this has been discussed before
https://photography-on-the.net …/showthread.php​?t=1519069
https://photography-on-the.net …read.php?t=1492​965&page=1

I suppose in my brain I see cropping as merely removing a portion of the image as if you were using scissors on a printed photo, resulting is a reduction of dimensions. My brain doesn't add in considerations of monitor resolution, photo resolution, megapixels, percentage of view on your computer vs my computer, etc etc. This is why I said cropping, or its definition, has become complicated as it has evolved over time to be adapted to digital photography.

It's really all the same. It's just this one new pixel-peeping aspect of "a sample cropped from a 100% view" that's new. Before we had pixels it wasn't an issue but maybe there was a print equivalent using magnifying glasses.