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Old 3rd of October 2004 (Sun)   #1
phizz6
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Default What is meant by 100% Crop???

In evaluating camera lenses and photos, I sometimes see examples stating they are 100% crops. Just what is a 100% crop?

When I shoot at Large Superfine with my G5 and open the photo in PSE 2, I see the following information:

Pixel Dimensions: W = 2592 pixels and H = 1944 pixels

Document Size

Width = 14.4 in
Height = 10.8 in
Resolution = 180 pixels/inch

If someone asked me to display a 100% crop of this photo would I crop a section of this photo using the crop tool or would I view the photo as actual pixels and crop a section from this view or are they looking for the entire photo with no resizing?
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Old 3rd of October 2004 (Sun)   #2
Sam North
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You crop the image down so you're left with a just a part of it without it having been resized - it's still at 100%. For example, it's useful to do this if you're sharing here about sharpness or optical problems.
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Old 3rd of October 2004 (Sun)   #3
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If you take your existing image of 2592 X 1944 pixels, and resize it to whatever your screen resolution is, (25.92 X 19.44 inches at 100 dpi, for example), then select a portion of that image, that will be a 100% crop.

The idea is to show your image without any interpolation, pixel for pixel at the largest possible size on your monitor.

If your monitor resolution is 100 dpi, you want the selected portion of your image to be exactly that.
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Old 3rd of October 2004 (Sun)   #4
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You can also select the magnification tool (magnifying glass) and right click - select "actual pixels" for 100% crop.
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Old 3rd of October 2004 (Sun)   #5
Belmondo
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Quote:
Originally Posted by ejwebb
You can also select the magnification tool (magnifying glass) and right click - select "actual pixels" for 100% crop.
That's a quick way to get a quick to get 'actual pixels' on your display, but if you want to save a portion of a photo as a 100% crop, you'll have to change resolution of the image if its anything other than the screen resolution of your monitor.
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Old 3rd of October 2004 (Sun)   #6
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Right, Belmondo - did not read the original post well...
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Old 4th of October 2004 (Mon)   #7
Rich_F
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With all due respect to Belmondo, I don't think that you want to think about resizing at all if you're creating a 100% crop. Indeed, using Belmondo's description, no-one could produce a 100% crop for me to look at, because they don't know the screen resolution of my monitor.

What it means is that the image is cropped, but not resized. That is to say, the cropped section still has the same number of pixels as that section had in the original. The intent is that you can look in detail at a small section of the orignal photograph without needing to download the entire thing.

[Of course, this never really works for jpeg unless you're very careful, as the cropped section will be recompressed, and so won't be identical to that same section in the original. To get around this, the crop should really be saved in a lossless format.]

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Old 4th of October 2004 (Mon)   #8
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Quote:
Originally Posted by Rich_F
[Of course, this never really works for jpeg unless you're very careful, as the cropped section will be recompressed, and so won't be identical to that same section in the original. To get around this, the crop should really be saved in a lossless format.]
I keep Jpegcrop on my machine for this very purpose:
http://sylvana.net/jpegcrop/
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Old 29th of March 2007 (Thu)   #9
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Default Re: What is meant by 100% Crop???

Quote:
Originally Posted by Basiltoo View Post
I keep Jpegcrop on my machine for this very purpose: http://sylvana.net/jpegcrop/
Will photoshop do a 100% crop? What proceedure is required?
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Old 29th of March 2007 (Thu)   #10
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Default Re: What is meant by 100% Crop???

open up the image in photoshop, then open up a new window w/ the dimension you want, say 640 x 480 (making sure that the DPI is the SAME). then drag the image into the 640 x 480 windo, position it so that you see what you want, go to save for web, select very high qaulity, and save...and there is your 100% crop.
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Old 29th of March 2007 (Thu)   #11
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Default Re: What is meant by 100% Crop???

Quote:
Originally Posted by TomBrooklyn View Post
Will photoshop do a 100% crop? What proceedure is required?
Check out these two posts. The second will link yu to another thread in which there are step by step instructions.

Quote:
Originally Posted by Robert_Lay View Post
Tutorial - How to do a Full Detail (100%) Crop in PSCS

The first picture below was re-sized from a 2592 x 1944 pixel original TIF to a new size of 400 x 300 pixels (downsampled by a factor 6.5) for posting of the full image on this forum as a JPG with Quality setting of 5. I changed the image to 8 bits per channel and used Image->Image Size and enabled resampling to down-size it to 400 x 300 pixels.


The second picture below is a Full Detail (100%) Crop from the same 2592 x 1944 original TIF. The crop was made of the clock face while displaying the picture at any magnification desired (It does not matter what magnification is in use as you do the crop). Do a simple crop with none of the options set - just drag the crop marquee to capture the area desired and execute the crop. It is important that no resampling be in effect during the crop.

Be sure that when you do the crop (if in Photoshop) that the width, height and resolution fields are all blank - otherwise it might re-sample the image.

I then converted the cropped image to 8 bits per channel and saved it as a JPG using a Quality setting of 5. At this point the 100% crop can be posted, and in this example it is 284 x 244 pixels.

The important aspect of this procedure that makes this a Full Detail (100%) crop is that the clock face is 284 x 244 pixels - the same size as in the original image. That's what makes it a 100% crop.

On all screens the Full Detail crop will display pixel for pixel, and the detail that you can see in that image is 6.5 times the detail that can be seen in the full image that was downsampled 2592/400 = 6.5, as posted here.
Quote:
Originally Posted by In2Photos View Post
If you are having a hard time trying to understand the methods for the 100% crop in the above post I have an example using screen shots here for CS2.

http://photography-on-the.net/forum/...=152215&page=2
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Old 29th of March 2007 (Thu)   #12
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Default Re: What is meant by 100% Crop???

Save it at 8 or higher imo.
5 is too low for a site like this.
5 is good for thumbnails on a gallery.

and dont worry about exact pixels matching your screen blah blah.
Just crop it and save it. Good enough for people to see the quality or ability of the lens you are trying to show.
Just DO NOT Sharpen or otherwise post process a 100% crop.
It kind of defeats the purpose of it. I see people doing it all the time.
Look how great this lens is!!! Yet its USM out the whaaazooo, resampled, and balanced.

I can take photos with a P&S and make them look like they came off a $3000 rig with post processing.
Sorry for the rant... just erks me when I try to find lens samples on the net.

Last edited by Uhland : 29th of March 2007 (Thu) at 09:02.
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Old 9th of July 2007 (Mon)   #13
Little Rocker
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Talking Re: What is meant by 100% Crop???

100% crop means pixel for pixel, no resizing just removal of pixels around croped area. When someone post a 100% crop each pixel you view on your screen should be a representative of a particular pixel on the poster camera sensor. Here is my latest 100% crop. Last night at the Old Mill, North Little Rock, AR. 5d with 85mm 1.2L Mki

If I want to get a 100% crop from Adobe Elements all I do isleave the crop resolution blank and it is an automatic 100% crop.

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Last edited by Little Rocker : 9th of July 2007 (Mon) at 08:19.
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Old 9th of July 2007 (Mon)   #14
Radtech1
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Default Re: What is meant by 100% Crop???

That is when you open your photo in Photoshop, zoom to 100% (which usually means you will not be able to see the entire shot, only a portion of it), then using the rectangle selection tool, select an area, then crop away every thing other than the selection. For the purpose of posting here, you want the selection to have a longest dimension of no more than 800 pixels.

The resulting image is a 100% crop. Because 1) it is at 100% zoom, and 2) it is a cropped portion of a larger shot.

When you post that, the primary purpose is to show sharpness (or lack of sharpness), or to draw attention to a certain area of a shot. It is not usually meant to be a final image for printing.

In the following, (from a thread I posted on regarding the Des Moines,WA area) the lower shot is a 100% crop.

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Quote:
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I am collating thousands of shots over 4 hard drives and I stumbled upon this. I don't know if we were taking off or landing, but it is in the evening, as evident by the west to east shadows. BUT, the cool thing is you can see the house my parents lived in!

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Old 9th of July 2007 (Mon)   #15
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Default Re: What is meant by 100% Crop???

Because the crop tool can be drug out (expanded)to cover any part of and including the entire image, there will almost always be some re-sampling done by photoshop when using this tool to crop. (Adobe sez it is not re-sampled, but pixels may be added or taken away to make the crop the size you wanted, whatever that means. I call it re-sampling) Doesn't matter at what magnification you are viewing the image. There are other variables involved also to further confuse the issue, such as the ppi tag for the image and whether the crop tool is set to inches or pixels. I've found that the only way to consistently get a crop without re-sampling is to use the rectangle tool, with the size set to the exact pixel dimensions you want. once dimensions are set this tool can then be drug around the image to cover any part of the image you want,but does not change size. The view magnification does not matter using this method as the crop covers only the actual number of pixels you have set. See this Adobe paper on image re-sizing and cropping for an interesting read: http://kb.adobe.com/selfservice/view...1327&sliceId=1
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