Definition please.

Call me stupid, and I expect some will, but I have yet to understand the terminology where someone states '100%' or similar, crop. What is a 100% crop? Does the percentage apply to the amount that an image has been reduced pixel-wise, as that to me does not make sense as it would appear that if an image were reduced by 100% then it would not exist. I can see where a 50% crop might apply, as the image size would be halved, again I assume pixel-wise. Answers on a postcard please, and keep it civil if poss.

I think a 100% crop means that a 1200 pixel wide photo is 1200 pixels wide on the original photo. Your viewing actual pixels on a monitor large enough to display it.

The person typing the phrase could mean something entirely different.

If that's what it means, then "0% crop" would be a more accurate description.

Perhaps, or pixel for pixel crop, or 100%view. Common phrases typically make little sense.

100% crop most likely is reference to viewing at a size that the software that 'fits' image pixels to the monitor pixels can fit 100% of the image pixels to the monitor, or 1:1 correlation between monitor and image pixels...you can fit 700x700 pixels at 100% on virtually ANY computer/laptop monitor today, even the cheap laptops with only 1366 x 768 pixel displays. OTOH a 1536 pixel vertical image only fits on the 768 monitor at 50%.

TerryMiller wrote in post #18130958
Perhaps, or pixel for pixel crop, or 100%view. Common phrases typically make little sense.

The meaning of the one under discussion isn't clear on its face. On second thought, it probably follows the convention used by printers. My old job included preparing material for offset printing. When specifying a reduction in size, you always wrote the percentage to be kept, not the percentage to be removed. If you wanted your 12"-wide artwork to come out 9" wide, your note said "Shoot at 75% [of original]," not "Reduce by 25%" or anything like that.

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oingyboingybob wrote in post #18130943
Answers on a postcard please . . .

What do you mean by this?

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I base it on PS, ergo, enlarge it until it says 100% at the bottom of the screen, or, I merely take a 1000 pixel square crop and post it.

Tom Reichner wrote in post #18131034
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What do you mean by this?

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A brief answer - not a 3-page report

https://en.wiktionary.​org/wiki/answer_on_a_p​ostcard

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Ok, well then I'll answer the question "on a postcard":

100% view means that each one of the image file's pixels is represented by one pixel on the screen of the device that you are viewing it on.

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Well done, Tom.

this may help:
http://www.juzaphoto.c​om/article.php?l=en&ar​ticle=9

not really a 'postcard answer'...but it's got pictures

Note: Pixel is defined as both a single point in a graphic image, and a single point in a monitor display.

100% = 1 pixel of graphic image per 1 pixel of display.

Without cropping anything, any time you use a photo editing or viewing tool, and ask it to display the image @ "1:1" or "actual size" or "100%" (name changes with software) as opposed to viewing the image using "Fit Image To Screen" etc.. the image likely becomes larger than the boundaries of your screen, and you are looking at a portion of the total image, or "crop" @ 100%

If you do not crop an image at all, and simply place it online for viewing in it's entirety, when you try to view it, it usually is scaled down to fit a screen.

However, if you view it full size,. ie: blow it up to "100%" or 1:1, so it is far too large for the screen, then you are viewing it at 100% size, and again, you are not seeing the whole image so you are viewing a crop.

The "100% crop" comes in when you wish to view an image (or actually a part of an image) on a screen too small to see the entire image @ 100%

The crop of the larger image remains fully on screen, rather than off the sides in some virtual space.
Portability is the primary reason for a 100% crop vs. the entire image that you would then view only a portion of, as large images can be many megabytes, where as a 100% crop can offer you the same peak at 100% scaled pixels without having to download a 20MB file, rather it can be mere kilobytes.

The "100%" attribute has no relation to the cropping amount. It denotes a crop so drastic that the retained image section will be small enough (in pixel dimensions) to be displayed on the monitor in a pixel-to-pixel view, which is also called a 1:1 view or 100% view. Hence the crop's name.

It's used to let other people see the finest image detail, undistorted.

Below is an image in the process of getting a 100% crop from it and the resulting 100% crop, posted to show the lens' sharpness.

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agedbriar wrote in post #18131218
The "100%" attribute has no relation to the cropping amount. It denotes a crop so drastic that the retained image section will be small enough (in pixel dimensions) to be displayed on the monitor in a pixel-to-pixel view, which is also called a 1:1 view or 100% view.

Actually, a 100% view does not necessarily involve cropping at all. For instance, I view images from my Canon 1D Mark 4 at 100% all the time, and they are not cropped at all in the horizontal dimension*. This is because my monitor's display is 5120 pixels across, and the images from the 1D4 are only 4896 pixels across.

*some of the image is cropped off vertically, as the resolution of my monitor is only 2880 pixels in the vertical dimension, and the files from my 1D4 are 3264 pixels in the vertical dimension.

To acquire a 100% view, cropping is only necessary if the linear pixel count of the image exceeds that of the screen of the device it is being viewed on.

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Images from my 1D Mark 2 or my 40D can be viewed without cropping in any dimension, as those files contain a much smaller pixel count. For example, here is what my monitor looks like with an uncropped 40D image being viewed at 100%. Not only is the image uncropped, there is even extra room left over around the image.