Histograms

Discussion in 'Photography Beginners' Forum' started by Stormchase, May 16, 2010.

  1. Stormchase

    Stormchase No longer a newbie, moving up!

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    I long for more info on this subject. I have read up on a little and watched some videos on it as well. Sorry if it is a beat subject but i have not seen much on here about it specificly. Im wondering how many people use it? Color fixing? exposure? Do you want a lazy W shape for the most part or? Again i am starting to understand it a lot more and now have my LCD display set to have it along with the shot. I sat outside shooting different sanerios of exposure to see the results. Im not happy with my picture only display anymore. It seems too unpredictable. Also when balancing color in PP I hear of a lot of people using the curve on the RGB. Do you use a histogram when doing that? I just wait untill the shot looks right to me. not really looking at the histogram. school me please! Everyones eye has a different preception so I believe the Histo does not lie! I know its a lot to toss out there at once but ...
    Thx
     
  2. pbelarge

    pbelarge TPF Noob!

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  3. Stormchase

    Stormchase No longer a newbie, moving up!

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    Great write ups! Thanks I learned some new things about color. AND more to read! So do you use them when you shoot? or work them in pp?
     
  4. Dallmeyer

    Dallmeyer TPF Noob!

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    I've found it's possible even to judge some aspects of sharpness of focus from the histogram.
     
  5. Overread

    Overread has a hat around here somewhere Staff Member Supporting Member

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    Dallmeyer care to expand upon that? I've never heard before on being able to judge sharpnes of focus from the histogram at all so I would be very interested to hear how you are approaching this.

    Also as for histograms I tend to use mine to judge a few basic points:

    1) Over and under exposure - critcal things in a shot as they can't be fixed at all in editing. I use this all the time (mostly to check overexposure) as on the camera LCD its far more reliable than the preview image and on most DSLRs the overexposed areas of the shot will blink to show you where they are. If its a little speck here and there I don't care, if its far larger and more distracting its time to adjust settings and reshoot (if you have the chance to).

    2) Get a general idea of the distribution of the light - idealy I want the main body of the histogram as far over on the right side of the histogram as I can, without clipping/overexposing the highlights (ie hitting the far right hand side). This means that in editing I have as much data as possible to work with as whilst you can tone down bright areas without problem, you can't brighten darker areas without introducing noise.
    Often you will find that you can't follow this rule perfectly and its one of those give/take situations.

    3) Set the histogram to show RBG colour channels (in camera again) to show if you are clipping a colour or not. Its possible to not overexpose a shot on brightness, but to clip a colour channel, which will have a similar debilitating effect on the end quality of the shot - flowers (esp yellow and red) are a good example of when you can clip the colour channel.

    4) In editing in the computer I tend to only keep an eye on the highlights area, again watching for overexposure and making sure that (when processing the RAW) I am not overexposing areas though my adjustments. Sometimes this means I have to process the RAW twice and merge the results so that I can get overly dark or bright areas to mix together and show details.

    I don't tend to try for any specific shape with the overall body of the histogram - a low/flat histogram will show an image with lower contrast, but I can fix this in editing. Otherwise its keep the brightness and colour channels from clipping/overexposing and trying to get as much on the right as possible. Otherwise the shape of the histogram can be whatever it wants and each shot I have taken tends to have its own unique shape to it.
     
  6. D-B-J

    D-B-J Been spending a lot of time on here!

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    i would also lik info on this! Thanks for posting the thread, as i was about to.
     
  7. pbelarge

    pbelarge TPF Noob!

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    I have the camera set up so when I shoot, the histogram comes up with the picture. In this setting the photo is small. I look for 3 things at this point.

    1. the histogram...am I clipping either end.

    2. are there any blinkees of blues.

    3. sort of the composition...

    If there is too much over exposure, I delete the photo and shoot again.
     
  8. Dallmeyer

    Dallmeyer TPF Noob!

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    Something i believe i've seen a few times now when ive shot repeated frames of a scene/object at the same aperture and shutterspeed, only adjusting manual focus. The most in focus image has higher values (or a more pronounced shape) at a certain point of levels than the more OOF ones. I'll attempt a test to try to validate what i'm saying and post the results.

     
    Last edited: May 16, 2010
  9. Overread

    Overread has a hat around here somewhere Staff Member Supporting Member

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    Ahh that would make some sense - the peek of each bar is essentially a measure of its contrast (you can see this if you edit a RAW shot and raise/lower the contrast slider only - the histogram bars will go up/down as well).
    This corresponds to sharpness because we see areas with high contrast differences as being sharp boundaries - thus giving us sharpness in the shot.

    Thus whilst it can be a measure of sharpness, its not going to work on a scene or shot which is naturally quite low in contrast/soft in lighting. Furthermore, as I noted above, you can boost the contrast values in editing and thus get that sharper image. So whilst it is a valid observation its not something I would concern myself with in the field - checking that the focus is in the right place is far more important.
     
  10. mommy22

    mommy22 TPF Noob!

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    Great thread! I use my histogram but don't totally get it. The links posted are really helpful.
     
  11. Hardrock

    Hardrock TPF Noob!

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    :thumbup::thumbup: This is also what I look for.
     
  12. shrutebucks

    shrutebucks TPF Noob!

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    pbelarge: great info, thanks for the links!
     

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