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Exposing with histogram

crollinsphotocrollinsphoto Member
edited June 2014 in wedding photography
Neil, for metering on available light you mainly used the histogram on the white dress and over exposed or corrected, that I understand. But when you put just a little bit of fill flash in the equation on it, does that change the exposure on the white dress or highlights with that little extra light?

Thank you.

Comments

  • ZenonZenon Member
    Yes it does. It is the same thing. You need to adjust flash but if you are at a perfect exposure as far as ambient is concerned you may not be able to reduce the flash enough. You can underexpose the ambient a stop or two if the flash is blowing out the dress. I typically shoot like that. If you have time you can shut the flash off and get the ambient where you want it (excluding the bride) and then turn your flash, shoot, check and adjust flash power for the dress.
  • So basically the histogram in the video is mainly for available light, once the flash is introduced for fill if needed you have to take into account ambient and shoot and experiment - a whole new ballgame, right?
  • StephenStephen Member
    edited June 2014
    Correct.

    The histogram is "accurate" if you only have available light. The histogram is used to make sure the "brightest relevant tone" is in the correct part of the histogram (in most cases, the bride's white dress).

    Once you add flash or another light source, the histogram doesn't help as much for the brightest relevant tone. You are now using the histogram to do a quick after-the-shot check to make sure the overall exposure is "ok." In this case, I often find it useful to combine the histogram reading with the blinking highlights display. The blinking highlights display tells which parts of the photo are overexposed.
  • ZenonZenon Member
    Yes. The flash event has not taken place so there no way for the cameras ambient meter to meter for it. TTL is very good but it is still ball park. The way only to accurately set flash exposure the first time is with a flash meter.
  • ZenonZenon Member
    Good call Stephen. I always have the blinkies on just in case there is something brighter in the background. Tougher to work with the histogram in that situation but you can use the blinkies to just get the dress the the point of overexposure and back off a tad. Your eyes get used to it and start judging exposure correctly as well. Sometimes you just gotta go for it and correct later.
  • ZenonZenon Member
    Forgot. I use anything that is white. Shirts, sweaters, cuff and collars, purses and even have used table cloth.
  • Neil vNNeil vN Administrator
    Here is the article on metering for the bride's dress and using the histogram:

    exposure metering for the bride & the bride’s dress

    A fairly simple way to get accurate exposure, is to use the histogram. I place my brightest relevant tone at the edge of the histogram. All the other tones will fall into place. In this way, you simply expose correctly for your subject – the bride in her white dress.

    Now if you add fill-flash, let's say at -2 EV, then the bump in exposure is fairly minimal. At -1 EV fill-flash, the bump in exposure is becoming more pronounced but is still well within what the RAW file is capable of handling.

    While it is good to have a methodical approach and a solid technical understanding, it is very often better during the shoot, to keep the momentum. To stop and fine-tune settings at 1/3rd stop or so, breaks the concentration of the person you are photographing. So most often, I would just keep to my correctly metered settings, and then adjust the RAW file later if needed. Or ... you can just take the ambient exposure down by 1/3rd stop if you are working at -1 EV fill-flash.

    When you get to the point that you are adding as much flash as ambient, it makes sense to pull down the ambient exposure accordingly by a stop.
  • Thanks everyone, I better get this down because the client will not want to stand there and wait for test after test until I get it right and get the session going.
  • ZenonZenon Member
    Good point as well Neil. When I stated 1 to 2 stops under ambient I was referring to indoor shooting. Outdoor close to to correct metered metered ambient exposure.
  • ZenonZenon Member
    This may help. I like Mark's videos.

  • Nice info. I keep forgetting about that aperture p setting.
  • I suppose I'd have to go to manual if I have my flash on a monopod for off camera flash and I backup with my camera to get a full length but keep the flash close to the subject for Aperture priority, right?
  • Not exactly on point with your topic but worth mentioning in regards to Histograms and their accuracy. I never use my Histogram. I use Sony Alpha A77, and A99 FF. They have EVF's that are amazing! As you make any kind of change to ISO, aperture, Shutter, EC, the change is instantaneous in the EVF and rear LCD. You do not have to chimp or guess. When I used Nikon I also never used my Histogram, Would make on the fly adjustments, chimp, and move on. It seemed I was wasting time trying to get the Histogram just right, i.e. having all the darks and lights lined up perfectly. Making adjustments on the fly, for me so much easier with an EVF., The Histogram was pretty much useless since using EVF's. Since switching back to Sony and their Alpha line with EVF's, haven't looked back... Just my 2 cents worth.
  • StephenStephen Member
    edited June 2014
    From Neil's post, I should have clarified something.

    If you are using manual flash and keep all your settings the same, then the histogram is generally reliable. The same amount of light will fall on the subject and scene.

    If you use TTL flash, then the histogram can become unreliable, since the amount of flash can fluctuate based on what the camera thinks. As Neil said in his post, if it's TTL fill-flash, the histogram doesn't get affected much and can still be used. When you are pulling the ambient exposure down far enough and letting the TTL flash light up the subject, that is when the histogram may become incorrect.

    For example, I can be outdoors and I decided to underexpose the background to allow TTL flash to expose the subject. I take my "test" shot or two and find good settings. I shoot using these settings for some length of time, and then the sun comes out or some other light source enters the scene. The settings I had originally will not work anymore; the histogram is going to show a different reading under the new lighting conditions. Either I continue to keep the settings and fix the exposure in the photos in post-process, or I readjust the settings quickly until I get acceptable exposure again. I usually readjust my settings again, but because I'm a recreational shooter, the subjects don't mind. I agree that constantly readjusting is probably not good if you have a paying client!
  • Good points, I never thought about using the histogram until I saw Neil talking about it.
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