Histogram question...

Discussion in 'General Discussion' started by Scott Sherman, Sep 30, 2005.

  1. Hi All,
    I usually shoot using the manual mode, move the first setting to the right F stop or speed as needed, then adjust the exposure to the center of the meter in the viewfinder or LCD screen on top of the D2x. Theoretically. this should yeild an image which has a reasonably good exposure. In reality, there are times when this is just not going to happen because of uneven or back light or glare, etc.

    Once the shot is taken, a quick glance at the histogram over the image in the back LCD screen clearly reveals that the Camera's exposure meter was fooled into an incorrect setting andd I can begin to adjust to a more desirable exposure. Unfortunately, this requires a trial image, and then a delete and then an exposure readjustment and then another trial image and so on.

    I don't think there is a way to set the camera exposure in difficult lighting by using the histogram in the camera until after you take an experimental image for proper setting and just reading the cameras meter reading is not always accurate.

    Here is my question. Is there a light meter with a histogram or some way to measure the scene to be shot with a histogram before taking the shot to avoid more over/underexposed shots the first time in challenging light?

    I suppose if a light meter were available, it would have to be a meter that is calibrated to a Digital SLR or to the specific camera body. (don't know)

    If anyone here uses or knows of such a light meter or other device, I would appreciate your shared experience or knowledge or perhaps you have a better way to evaluate your exposure in tough lighting situations. I know experience and intuition is the best combo for some. I am not that smart unfortunately and frequently don't guess the best exposure all the time.

    Thank you
     
  2. Well, you could use your spot meter, picking the part of the subject where you have a good idea how much EV adjustment you will need to make. I use this method quite often in difficult lighting and usually nail the exposure - it does take some experience. However, if you practise, with the immediate feedback of the histogram, you pick it up quickly. For example, when I am shooting birds against a summer blue sky I will shoot matrix and +2/3EV. On a bright hazy day I might shoot +1EV. Usually I will take a sky shot and check the histogram to confirm my guess, but often there is no time - you have to be adjusted the EV as you bring the camera to bear on the bird.

    How I expose with the histogram varies with my end objective and the ISO. If I am shooting a dark scene at ISO 100, then I will want the histogram bunched up to the left, but if I am shooting at a High ISO, I will want the histogram spread across the range, correcting in post processing, to avoid excessive noise.

    My 2 cents...
     
  3. Thanks for your response Rory,
    I suppose this is as you say based on experience. I find the histogram very helpful but you're right, time can be constraining as in shooting birds etc. AE is pretty good and if it is rush shot, I will shoot brakets. I wish there were a way to see the histogram before the shot. I guess this is not possible since the histogram, (I think, measures the exposure in a photo).
     
  4. Wilk

    Wilk

    246
    Jul 28, 2005
    I sure haven't found a magic bullet. Don't really think one exists. For me, it's really just a matter of experience. Really when you think about it, you're still a lot better off than with film. I got so sick of bad exposures (shot mostly kodachrome, chromes are most unforgiving) I ended up just bracketing anything I really cared about.

    Getting used to not just shooting, but post processing with my new D70 IR mod, I'm doing very heavy bracketing, just to see if there are times where serious under or over exposure can yield some interesting results in post processing.

    Just be thankful that you can hit that delete button, and it don't cost a dime :eek:). You've got something better than the best light meter in your camera... taking and correcting is just the nature of the beast. I'm sure, as we all learn to recongnize more and more the actual luminocity of the subjet, we all get better at guessing the first exposure, but again, at least missing on the first try doesn't cost a thing.

    Steve
     
  5. Wilk

    Wilk

    246
    Jul 28, 2005
    BTW... if you want the best book going on light, luminocity and the histogram, ron resinicks book is just fantastic. It's not for the timid or those looking for that non-existant "easy answer" - it's very deep and technical, but well worth reading and reading again till you understand it - I'm on my third read, and I'm still scratching my head on some things, but I understand light a WHOLE lot better now than when I started.
     
    Last edited by a moderator: Sep 30, 2005
  6. Chris101

    Chris101

    Feb 2, 2005
    Arizona
    Steve, you took the answer right out of my mouth (well, about 3 hours before I even read the question.) The first (and arguably best) part of Ron's book discusses a method for 'preguessing' the histogram - by asigning luminosity values to certain colors and lighting.

    Remember Scott, that the light meter will say what exposure will bring the metered area to an average of the middle tone. 18% gray if you wish, although it is unusual that something is actually gray, whatever color it is will be the same brightness.

    So in addition to centering the meter at zero, you also need to apply 'exposure compensation' to the settings. Move the needle to toward the + if you want the metered thing to be brighter than mid-tone, and toward - if you want it to be darker.

    I don't know of a meter, outside of your trained mind's eye, that can previsualize a histogram.
     
  7. Hi Steve and Chris,
    Thanks for the info, I went to Ron's book website. It looks interesting, it is about $84 for about 100 pages. I also noticed another Digital Photography Book 123di which is about three thousand pages and about $50. Has anyone seen both for comparison? I am somewhat familiar with Ron Resnick from the forums and his website and he is a good guy and very knowledgable. Don't know that I would want to buy both.
     
  8. Chris101

    Chris101

    Feb 2, 2005
    Arizona
    I haven't read 123di, but have read a bunch of other photo books. Ron's book is unique and presents a histogram based approach to exposing and processing digital photos that you won't get from other books. The first part of the book is exposure by lumnosity technique, the second part is about how to curve to the histogram followed by some hardware stuff.

    If you are looking at it in terms of pages per dollar, Ron's book will lose. However Digital Photography - Acquisition and Processing Techniques provides a unified approach to shooting and processing that is not available in any other book, regardless of thickness.

    I don't use the techniques as taught by the book, however I have adapted many of the ideas to my own style: I can usually set the EC correctly the first time, and I use some Ron's histogram based, curve techniques in ACR (instead of NC.) The very sweetest nugget in the last part is the hand-over-arm, steady pose for hand-holding with a long lens.

    Well, that and I couldn't imagine reading a 3000 page book.
     
    Last edited by a moderator: Oct 1, 2005
  9. MontyDog

    MontyDog

    Jan 30, 2005
    #1064 - You have an error in your SQL syntax;
     
  10. Gale

    Gale

    978
    Jan 26, 2005
    Viera Fl
    Recommend Ron's book over the other you mentioned.

    I did have a 123 thingy and the colors and layout for me were just not reasonable at all. Whether that has changed I don't know.

    I would send you my 123 thingy but is rather outdated, since I got it when I got the CP5000.

    Go with Ron for sure.
     
  11. JB

    JB

    502
    May 27, 2005
    Washington, DC
    I second the Ron Reznick recommendation

    Ron Reznick's workshops cover this extensively. I would also recommend his book. Do both for best results. Highly recommended.

    http://www.digital-images.net/eBook/body_ebook.html

    The RGB histogram on the D2X is simply the best exposure tool I have ever used. Using it with the expirience that Ron shares, knowing how to use the various metering modes of your camera, and you will get excellent exposures.
     
  12. heiko

    heiko

    May 15, 2005
    Israel
    Scott,

    I've got Ron's book and it's worth reading several times - and I can subscribe to Paul's suggestions.

    Regarding 100 pages for $84, well, you get everything you want to know in a much more concise way. Ron simply doesn't waste your time - everything is just down to the point. That's how I feel about it.

    Regards,
     
  13. Well it seems unanomous, his book is a winner. I decided to purchase it, but it seems that he will be updating it end of October, so I don't expect it will be ready for distribution until the beginning of next year some time, hopefully sooner if only available on CD. I woul like to see a download version of this one.

    Thanks to all who took time to contribute
     
Loading...
Similar Threads Forum Date
Questions about beer General Discussion Sep 15, 2017
Sekonic Classroom Histograms General Discussion Dec 4, 2009
AUTO ISO = crappy HISTOGRAMS General Discussion Apr 24, 2009
Histograms that make you go "hmmmmm" General Discussion Apr 21, 2009
Focal Length Histogram - How can I do it? General Discussion Nov 5, 2007