Canon EF 100-400mm f/4.5-5.6L IS USM - AKA The Dust Pump

Burnaby wrote in post #8212475
Hawaii or Iceland?

big island, lava tube to the ocean

guys, some pigeon shots ! all handheld

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Clear sky last night, managed to snag this, hand held. Need to get a monopod one of these days.

IMAGE LINK: http://www.flickr.com/​photos/nate1280/369047​5150/

I've asked this before and have never understood the explanation, but as you're using the expression I'll try again. What is 100% crop? The term doesn't mean anything - take away 100% and you have nothing left.....?

A 100% crop normally means you've cropped it down so that what's left is shown at one image pixel to one screen pixel.

Isn't that a function of display rather than crop?

So what exactly did the poster of the moon photo (lovely picture) mean by 100% crop?

I'm only telling you what it means. It permits the viewer to see all the detail that is in the image. It really means 100% zoom or display, but you need to crop the image so the viewer doesn't have to zoom in, hence "100% crop", logical or not.

The original image was 3888 x 2592; it was cropped down to 1519x1013 (which on my screen i can see at 1:1 with no scrolling). So when I look at it on my screen its 1:1 without zooming. Altho, its resized from posting to flickr a bit (and forum posting rules). That was always my understanding for 100% crop.

http://www.pbase.com/w​lhuber/100_crop_ dunno if that helps explain 100% crop any better...

peterbj7 wrote in post #8227251
Isn't that a function of display rather than crop?

So what exactly did the poster of the moon photo (lovely picture) mean by 100% crop?

"100% Crop" is simply a coined phrase that is used because nobody has a better phrase to use. It only pertains to viewing something on a computer monitor, so yes, it relates to the display, simply meaning that a user crops an image so that the cropped portion maps 1:1 to the pixels displayed on the monitor, similarly to viewing an image at 100% resolution, but with only a portion of the image that will fit into a "normal" monitor's viewing area.

People display images like this typically to show sharpness or the lack of, or to show other image characteristics like noise. This is because it's the only accurate way of viewing such fine, discrete detail on the screen (at smaller resolutions the image is compressed, losing such detail in the process).

Moon shots like the above many times are cropped closely simply because it takes quite a long lens to get the moon to fill much of the image and so with "shorter" lenses details that we might want to reveal are lost in the small size and viewing compression here on the web. So, you crop the moon to display at a reasonable size, and assuming your shot is reasonably sharp a 100% crop will show all of that detail.

Good explanation Tony

I think I follow, but I need to ponder it some more. Who came up with such a crazy and non-intuitive name? It has absolutely nothing to do with cropping as such, except incidentally.

Since we're talking about mapping the original image onto the display screen, why not something like "precise map"?

Now, is a "100% crop" seen the same way by all viewers? Can a "crop" (I prefer the term "view") be 100% for one person but not for another person with a differently-sized monitor?

As you say, it may come out a different size on a different monitor, but the point of it is that it shows the full detail of that part of the image. I do agree the name is not intuitive.

Back in the '60s, I cropped with the enlarger and an adjustable mask over the paper. When I crop a photo, I'm looking for the finished size and placement of the subject. Whether I crop for an 8x10, 5x7, or rotate the image, I think of that as cropping. Old school stuff...

http://desktoppub.abou​t.com …y/glossary/blde​f-crop.htm

Definition: To cut out or trim unneeded portions of an image or a page is to crop. Cutting lines, known as crop marks, may be indicated on a print-out of the image or page to show where to crop.

This Brown Pelican is from the first time I went shooting with the lens. Not the sharpest, but still good.

peterbj7 wrote in post #8227962
I think I follow, but I need to ponder it some more. Who came up with such a crazy and non-intuitive name? It has absolutely nothing to do with cropping as such, except incidentally.

Since we're talking about mapping the original image onto the display screen, why not something like "precise map"?

Now, is a "100% crop" seen the same way by all viewers? Can a "crop" (I prefer the term "view") be 100% for one person but not for another person with a differently-sized monitor?

Life's too short bud ... just accept the flaws in our beloved language and move on, as I fear this one is way too far down the line to change it now

Maybe to help you get over your hurdle with this, think of it as "a crop at 100%" (zoom), not 100% of it being cropped ... ie. a 1:1 pixel ratio from image size to crop size, as I believe this is what it refers to so is in fact quite logical.