I know what cropping is, but I cannot understand how to do a e.g 50 and or 100% crop. Are there certain parameters in a cropping program that let you the size of a crop.
Thanks for your help.
Wally
The "100%" refers to viewing the image at 100% size on your display. With current cameras, you'd need higher resolution displays than are currently made to view the entire image at 100%, so you can only see a portion at a time. When someone posts a "100% crop" or a "50% crop" here, they are viewing the image at 100% or 50%, then cropping by selecting a portion of that image and copy/pasting it into a new file, which they post here.
Personally, I use Photoshop for that, setting the View to Actual Pixels for 100%, then using the marquis selection tool (usually with a fixed size since the max width of an image here is 800 pixels) to copy the desired portion and paste it into a new file.
Another method would be to use any image viewer (DPP, etc.), set the view to 50% or full size, reduce the size of the window to something managable, then take a screenshot of that active window (Alt-PrtScn on Windows then paste it into some other program, or Command-Shift-4 then Space Bar on Mac, although on Mac it's easier to just set the view to 100% then useCommand-Shift-4 and drag the selection box to grab a portion of the image which is saved to the desktop).
For example, here's an original image and a 100% crop of that image:
Note that you have to actually show the full size of the cropped image, which I why I selected an 800 pixel wide portion of the original image viewed at 100%. If you display the cropped image at less than full size, like the image below, it's no longer a 100% crop. That's important not just for viewing size - notice that the noise which is evident in the full size 100% crop above (ISO 3200 on a 7D) is much less evident in the smaller image below. The noise is also less evident in the original image, which is why extreme cropping has a negative impact on a final image.
Hope that helps.
--John
You don
On Flickr - Namethatnobodyelsetook on Flickr
R8 | R7 | 7DII | 10-18mm STM | 24-70mm f/4L | Sigma 35mm f/1.4 | 50mm f/1.8 | 85mm f/1.8 | 70-300mm f/4-5.6L | RF 100-500mm f/4-5-7.1L
Wally
You see people say 50% and 100% crop, I am not sure they are mathmaticaly trying to make those exact crops. I haven
Originally Posted by HDNitehawk
The main (perhaps only) reasons would be to compare performance of different cameras/lenses or illustrate some technical point about an image. If someone actually needed to use a 100% crop as a final image, it would be time to get a longer lens...
The reason for the exact 100% crop size is to compare lenses, or show camera noise levels. That sort of thing. It can show lens sharpness, contrast, amount of chromatic aberations on high contrast edges. For comparisons, it
On Flickr - Namethatnobodyelsetook on Flickr
R8 | R7 | 7DII | 10-18mm STM | 24-70mm f/4L | Sigma 35mm f/1.4 | 50mm f/1.8 | 85mm f/1.8 | 70-300mm f/4-5.6L | RF 100-500mm f/4-5-7.1L
I could see where it isgood for comparative purposes. Usualy when someone mentions a 100% crop they are trying to either show how sharp the image is or a flaw. Most of us know what 100% looks like on our own computer.
The only lens I have that is likely to be croped to 100% for a final image often, is the one that really can't get any longer with a truck load of cash. The 500mm its is very common especially with small birds, like a finch atminimum focal distanceyou wouldhave a sizeable crop (not 100% though). Still you wouldn't do the exact number 50% or 100%.
David
I like to do big prints. And the way I judge how well my lens and camera perform together is by the 100%, 200%, 300% to 500% full views on the computer screen. The ones that can only make it to 100% are usualy marginal. and can't take much croping at all for a big print. At least for my use.
Actually when I read the OP, I was thinking finished product and not comparison
I can releate to the story about the zooming in on the brand name of the zipper. I don't know how many times I have had my 5D IIwith the 35mm lens on and someone ask me to "Zoom" in with my camera to see some detail or what somthing says. At least a dozen times I have had to explain the diffrence in a wide lens, telephoto lens and zoom lens to someone asking. ...But I still take the picture and zoom in on the viewer to see if I can see it. The most memorable time someone asked was at Mt Rushmore. I had the 500mm with 1.4x on and we took a head shot of George Washington, zoomed in on his eye lid. There is a steel spike sticking out of the eye lid on George Washington.
Rick
An x% crop is simply a portion of the original image that has been resized to x% of its original pixel dimensions.
Let
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