Definition please.

Thanks everyone.

Tom Reichner wrote in post #18131235
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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.

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Yes 5K monitors are very nice, I didn't realise that at 10Mpix 40D image would fully fit too, The images from my old 300D, at 3012×2048 seem really small at times, so much so that I keep double checking what setting I'm using., or that it hasn't been cropped. Although I went with a Dell system and monitor, I believe it is the exact same display panel in both my monitor and your iMac. The really great thing about 5K is that I can edit 4K video (and the full 4096×2288 Cinema stuff at that), at full resolution with room for toolbars etc.

One other thing I will say I like the way that Win10 now handles scaling high res monitors. My friend struggles to read anything on his 2.5K iMac screen and has to run it in a lower (non native) monitor resolution, which really seems to badly affect viewing quality. You can now have windows scale the desktop by quite large amounts, I usually run the 5K at 200%, so it looks like 2560×1440, but for him I would run at 250%, everything is bigger, but since it is still at native 5120×2880 the font smoothing etc is still very good and it doesn't hurt the observed quality, and in all the editing programs I use, selecting 100% or 1:1 view still produces just that, something you don't get when changing the screen resolution away from native.

Alan

Well, hey, I'm a month late in posting this (thanks to health problems) and it's in the middle of the "early hours" (sleep disrupted from the above problems) but still, I think it would be helpful to address the original question, "What is a 100% crop?" in the context of an open photography forum such as good old POTN!

In fact, you do see this phrase crop up often when a poster is complaining because their photo(s) to them look excessively noisy, or out-of-focus, or not satisfactory "sharp" in, say, details that are meaningful to the photog. "Post a 100% crop" is, in fact, an actively common and meaningful request.

Now, these discussions can get a bit lost when we can't view the photo in question, but also if we don't get a close, clear look at the details or the noise in question. As has been said, you can view a photo at "100%" in a lot of software, but you are at your computer and I'm at mine, and the only way I can get the full photo and view it large is if I can get the original photo file (one not shrunken/compressed in a way that will tend to "smooth out" such things). To do that, you would have to get that original file to me! And then, my monitor/viewing device (as well as my software on hand) would have to be able to handle the large sizes (in pixels) of any modern image, certainly without having to scroll all over the place! Heck, I've shot with plenty of digicams where the image size (in pixels) would out-do out-do most modern monitors, even those 4K/5K systems! And, iff you depend on shrinking/compressing images so that viewer can see the whole image but st the same time can distinguish these pesky problems, well, good luck, it likely won't happen!

But, in the digital imagining world, and Web forums like this, there is the crop that can help in this. As has been said, an image viewed at 100% will map 1 image pixel to 1 monitor RGB pixel. Now, the "100% crop" approach comes into play. Assuming that close view is centered on part of the image that is of interest, then you simply crop that portion, a large enough crop to hold that part of the image, while being "small" enough to display on a "normal" display. As has been said, modern monitors will typically display at about 100 pixels per inch. Displays come in various sizes, and you can take that into consideration. I often use a smallish laptop, maybe a 15" screen, so large images at 100% can get pretty messy, but say if you use reasonable pixel dimensions it's much better.

So, say you have a portrait of a person (or hey, of a squirrel) and you want us to chime in about noise/sharpness/focus, and one of us pixel-peepers says "can you show us a 100% crop of a meaningful part of the photo, such as an eye", well, it's pretty simple, you view the image at 100%, select a part you want to "share", then use your cropping tool to "cut out" that portion, making note of the resulting pixel dimensions. Like I said, on my laptop I'd probably prefer some thing of say 1280 pixels at the widest (the POTN max size) although for a vertical orientation, well smaller could be better, so say dimensions of max width of 1280, height of (maybe) 800-900 pixels.

Now, like I said, you need to figure these dimensions out in the cropping stage. Too big, and Web software will probably shrink it, that's no good, and too small and we'd all have to squint and strain to even know what we are looking at!

Just one more point: the question does come up "Why? What does it matter? Who looks at photos at 100%? Only pixel-peepers, right?"

Well, I'll only speak for myself here, but I do view meaningful images at 100%, sometimes just a glimpse, but yeah, if noise, sharpness, proper focus is in question then yes, an enlarged view can help you analyse such things, not to be picky, but to get the best results. In fact, some sharpening software will show a 100% "thumbnail" so that you can see how your processing works at the level of fine detail!

So, yeah, there are "Picky pixel-peepers", sure, and there are also plenty of pics that just don't need (or deserve) that level of attention! But I tend to look at a "good shot" as being print-worthy, not 4x6 snapshots to play with, but ones that can be printed at a decent sized and framed and hung, and also, I've taken plenty of shots, especially when out "in the wild", that need some generous cropping to get a decent composition, and boy, even an 8x10" print can show up some of those image defects, and if a 100% view will help me to sort things out and hopefully properly process an image, then, well, "Pixel Peepers Arise!"

Anyway, I hope this clears things up concerning the actively used phrase "100% Crop"!