100% Crop: Explain it like I'm a 4 Year Old

Discussion in 'Digital Photography' started by Designer Dale, Dec 17, 2010.

  1. Designer Dale macrumors 68040

    Designer Dale

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    Folding space
    #1
    Hi there friends and neighbors.

    I see the term "100% crop" often on the forum, but I have trouble wrapping my tiny brain around it. To me, 100% is all of something and "crop" means cut off. So if I do a 100% crop of my little finger, then I have 0% little finger left. Ouch! This can't be right. If it means "This is 100% of the original", then it's full frame or uncropped. 0% crop.

    Enlighten me and show me the way, oh most excellent brothers and sisters.

    Dale
     
  2. iBookG4user macrumors 604

    iBookG4user

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    Location:
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    #2
    Basically, a 100% crop is where you are seeing, for example, 900x900 pixels of the image on 900x900 pixels of the screen. Cameras nowadays take pictures at a far larger resolution than our monitors can display like 3888x2592 (10MP from an image on my 40D).

    Say I have a MacBook Pro with a monitor that has a resolution of 1440x900. To view a 100% crop of that image, I would have to zoom in to that image until I am viewing just 1440x900 of that image on the screen. So a pixel in the image would be represented by a pixel on the screen. In other words, I would have to view 13% of the total image to see a 100% crop. Hopefully that made some sense :eek:
     
  3. Designer Dale thread starter macrumors 68040

    Designer Dale

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    #3
    Is this the same as hitting Command-0 in PhotoShop? A 1620x1050 desktop design blows up to 1620x1050 on my screen? I understand "working at 100%" in design, but not cropping a photo.

    This is where I get lost. How does 13% in the above example become 100%? And since we all have different screen size and resolutions, isn't 100% crop different for each of us?

    Dale
     
  4. VirtualRain, Dec 17, 2010
    Last edited: Dec 17, 2010

    VirtualRain macrumors 603

    VirtualRain

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    Vancouver, BC
    #4
    Literally, it means "A crop of an image displayed at 100% zoom".

    If you are in Photoshop, and use the View > Actual Pixels... that's effectively 100% zoom and if you take a crop of that, you have a 100% crop :)

    EDIT: @Dale... you got it. What's left over after the crop is still zoomed to 100% so it can keep the name 100% crop. The 100% refers to the zoom, not the portion of the image you kept. Of course, a 100% crop is only valid if you don't resize it! :)
     
  5. DeG2 macrumors newbie

    Joined:
    Jun 18, 2010
    #5
    I appreciate the question and answers.

    So what you're saying is a 100% crop is n camera pixels displayed in n monitor pixels. What about a 50% crop? Is that 2xn pixels displayed in n monitor pixels? Or would that be 2x the height and 2x the width (meaning actually 4xn camera pixels displayed in n monitor pixels)?
     
  6. VirtualRain macrumors 603

    VirtualRain

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    #6
    Technically you're correct, a 50% crop would presumably be a crop from an image at 50% zoom, but I've never come across anyone using the terminology in a generic way like that. It's either a 100% crop, or it doesn't matter. :)
     
  7. Ruahrc macrumors 65816

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    Jun 9, 2009
    #7
    Dale- seems like you got it now.

    I am not sure I have seen the exact terms 50% crop, but I have seen 200% crop used before. Anyways, the principle is the same.

    The usefulness of 100% crop, for example when evaluating sharpness, is that one can see the actual pixels in an image, without having to load or display the whole thing. If the corner performance of a lens is in question, a 100% crop of the corner is easier to show and compare than the full images viewed at 100%.
     
  8. Arminator macrumors member

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    Feb 10, 2010
    #8
    My son, youre to young for working with computers. Go outside and play ball :D
     
  9. Designer Dale thread starter macrumors 68040

    Designer Dale

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    #9
    Makes sense, I guess. According to the link below, my monitor has a DPI of 96. Would your 100% crop thing be physically smaller on it that on a 72 DPI screen?

    Wouldn't "1-1 crop" be more correct? You are cropping an image that is 1 px - 1 px on the screen.

    What's My DPI?

    Dale
     
  10. Ruahrc macrumors 65816

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    Jun 9, 2009
    #10
    But the same 100% crop shown on 2 different monitors of differing DPI would still show the same detail level because it is still 1px for 1 image pixel

    The term 100% comes from the zoom level of the picture, not the size of the physical representation on the screen.

    Ruahrc
     
  11. Designer Dale thread starter macrumors 68040

    Designer Dale

    Joined:
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    Location:
    Folding space
    #11
    Ruahrc and VirtutalRain: Thanks for the explanations, I have it now. 100% crop is one of those terms that has been illusive to me. If I ever have to use this, I think I will go with "Cropped from 100%" instead. That is more literal for me.

    Dale
     
  12. rusty2192 macrumors 6502a

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    Location:
    Kentucky
    #12
    I've been wondering this same thing since getting into these forums. Thanks Dale for being brave enough to ask the question. And thanks to everyone who answered. I now understand it. At least I think I do :p
     
  13. FX120 macrumors 65816

    FX120

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    May 18, 2007
    #13
    1:1 = 100% :cool:
     

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