A&P noob question: histogram

Discussion in 'Lifestyle' started by horselover fat, Jan 10, 2009.

  1. horselover fat

    horselover fat in your driveway stealing your internet

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    how should a histogram look like?

    i have seen numerous comments that people check their histograms after taking a practice pic then adjusting setting via that

    this is probably a vague question with many different variables, so if im missing something plz inform me
     
  2. EWhytsell

    EWhytsell New Member

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    Lots of variables, but mostly you try not to have the curve cut off on the left or right edges.
    Thats the basics anyway.
     
  3. horselover fat

    horselover fat in your driveway stealing your internet

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    since i have a couple more noob questions, ill throw them in here


    when i open a nef file in either lr2 or the photoshop it displays the picture as how i think it should look, correct exposure, brightness/contrast

    but when i export it into a jpeg it isnt what it looks like from the preview in lr2 or ps, to bright, like its overexposed

    i believe the picture is overexposed but why does lr2 and ps display it differently then it saves it as?
     
  4. EWhytsell

    EWhytsell New Member

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    Are opening the file in something other than PS or LR when your seeing it different? Other programs won't necessarily display files correctly. Some even use their own adjustments.
     
  5. horselover fat

    horselover fat in your driveway stealing your internet

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    no, its in ps or lr then when i export it the nef to a jpeg its different
     
  6. Cnote67250

    Cnote67250 Active Member

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    Are you looking at both the raw and the jpeg in PS, with the same crop/zoom level as well?
     
  7. horselover fat

    horselover fat in your driveway stealing your internet

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    no, im looking at the jpeg in windows
     
  8. TheManLouisianaFace

    TheManLouisianaFace and decide!

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    or no data on the left or right, in which case you'd want to use the levels sliders to adjust.
     
  9. TheManLouisianaFace

    TheManLouisianaFace and decide!

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    Embedded color profile? In camera settings?
     
  10. Cnote67250

    Cnote67250 Active Member

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    I don't see any differences with a jpeg saved from a raw in PS. However, if I save a jpeg, and open it up using windows picture and fax viewer the picture tends to look "brighter."
     
  11. horselover fat

    horselover fat in your driveway stealing your internet

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    so is there any way to change the way that microsoft displays pictures?
     
  12. TheManLouisianaFace

    TheManLouisianaFace and decide!

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    it's you in camera processing most likely...which doesn't get applied to the raw...check your settings or reset the cam...
     
  13. horselover fat

    horselover fat in your driveway stealing your internet

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    wat in camera processing? like retouching?

    i dont use any of the editing features in camera
     
  14. jared_IRL

    jared_IRL OT Supporter

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    Your colorspace is wrong for windows.

    I'll bet you're using either prophoto or adobe 1998.

    Bridge/LR and Photoshop are color managed applications. Most of the rest of the world is NOT.

    So when you save your jpg's, do the following first: (in photoshop)

    edit>convert to colorspace>destination profile = sRGB



    As for your histogram, in the camera you want to look at 3 things:

    1. Nothing is touching the absolute left of the histogram - this means you have black areas with no detail. (underexposed)

    2. Nothing is touching the absolute right side of the histogram - this means you have white areas with no detail. (overexposed)

    3. Most of the information is somewhere around the halfway mark, or on the RIGHT side of the halfway mark. There's a phrase that was used with chrome slide photography for years that also applies to digital photography: MORE RIGHT IS MORE RIGHT. Your cameras sensor is linear. there is more data available to your camera on the right side of the sensor than there is on the left. If you expose to the left of center on the histogram, then try to bring your exposure up, you'll introduce noise to your data. If you expose to the right and bring the exposure down, you suffer absolutely no consequences. Also, you have a better chance of saving blown out areas in a raw file than you do 0 detail black areas...
     
  15. ZCP M3

    ZCP M3 Active Member

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    I did not know this. :bigthumb:
     
  16. GlobeGuy

    GlobeGuy New Member

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    You want to do exactly the opposite of what you wrote here. You can still pull up nice details from underexposed pictures but once a detail is blown out it's gone forever.
     
  17. EWhytsell

    EWhytsell New Member

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    Hehe this is likey true since in astrophotography those pictures I post have a histogram were nearly all the data never gets further then 5 to 10% from the left. If I blow out something (star or detail in a nebula) there's nothing I can do to save it short of shooting a series of lower exposures and masking them into the final image.
     
    Last edited: Jan 10, 2009
  18. jared_IRL

    jared_IRL OT Supporter

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    What? No, no you don't.

    I never, ONCE said blow out your details. Ever. I said expose to the right. If you can't expose to the right without blowing out your highlights you're doing it wrong.

    Saying you can pull nice detail out of underexposed images is complete bullshit. You introduce TONS of noise into your image when you do this due to your software trying to create detail that does not exist.

    Show me ONE shred of evidence to back up this statement.

    Here's some reading for you:

    http://www.luminous-landscape.com/tutorials/expose-right.shtml
     
  19. jared_IRL

    jared_IRL OT Supporter

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    again. blowing out your highlights =! exposing to the right.
     
  20. jared_IRL

    jared_IRL OT Supporter

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  21. EWhytsell

    EWhytsell New Member

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    I won't argue since your right in daytime photography and the stuff I do involve a process that could not be duplicated in 99.9% of daytime photographs.

    Oh and the fact that its impossible to expose to the right in the example I gave since a 3-5 min exposure results in a tiny sliver of information on the far left edge:)

    Very cool article also.
     
  22. jared_IRL

    jared_IRL OT Supporter

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    yeah, your nightime multi exposure stuff is something I have NO clue whats going on with. But whatever you're doing is working, so keep on going with it.


    What i'm talking about applies to single exposure images where you won't have the chance to merge multiple frames to gain more dynamic range.
     
  23. GlobeGuy

    GlobeGuy New Member

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    I see what you meant by exposing right, but I don't see the point of telling someone to expose to the right if they are shooting something static. Just expose it correctly right off the camera. That's why I went with assumption that the OP was talking about more dynamic lighting conditions.

    For photojournalistic stuff where lighting condition changes constantly, underexposure > overexposure.
     
  24. 1992 240SX

    1992 240SX New Member

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    I usually underexpose about a stop...I hate seeing blinking all over my screen. Id rather just bring out the shadows later.
     
  25. EWhytsell

    EWhytsell New Member

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    So my 40D's highlight warning could be more conservate then I'm thinking and I don't really have to worry as much about making things blink? I'm guessing a large blinky area isn't a good enough though.
     

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