Photos too dark

I’ve been told by a number of people in recent times and have received a number of e-mails stating that the photos on my website are too dark, somewhat under exposed. This has always puzzled me as while the photos do look a little on the dark side, the exposure is almost always set correctly based on my camera’s light meter when I’m composing shots. This has almost made me believe that the light meter was faulty but looking at the photos on the screen on the back of the camera I can see that this is not the case. Time to delve deeper.

In order to publish my photos to the web I have to extract image data from the RAW files my camera generates and compress into a JPEG file that can be delivered to and opened by a web browser. To to this I make use of dcraw, a nifty little application authored by Dave Coffin. This will pass data out from the RAW file to be collected on stdout by a program such as cjpeg.

As I like to publish exactly what my camera has stored to the file (with a little compression for portability) I don’t use many of the options on dcraw, just invoking the ones that read the values from the file it’s self and use those. Looking down at the parameter list I suddenly wondered if perhaps I’d mistakenly used the wrong parameter somewhere, so I started to check each one I’d used against the documentation.

Everything checked out apart from one very small anomaly; -w was documented but -W was not. The documentation states that -w tells dcraw to use the white balance value stored in the RAW file when processing which is what I wanted but -W seemingly did nothing except it threw no errors when used so must have some function.

Plunging deeper into the documentation I found the bombshell I was looking for; -W is used for switching off the exposure compensation value contained within the file! I ran a quick test and changed to lower case while decoding a photo I’d taken recently and the effect was perfect, the correct brightness and also the correct white balance (it hadn’t been far wrong but was much better now).

I’ve now updated my script that I use to call dcraw to invoke the correct parameters and hopefully dark photos will be a thing of the past on my website. The thought of having to re-decode some 3000 odd photos that have already been uploaded doesn’t fill me with joy though…

   

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5 Comments

  1. Bryan Said,

    December 3, 2011 @ 8:55 am

    IF you have Photoshop use Adobe Bridge open all files and you can simultaneously fix the white balance on all the pictures. If you do not have Photoshop I would highly recommend it. Bridge is such a great tool for photos, you can get a free 30 day trial at adobe.com.

    I am a web and graphic designer, I do not work for adobe.

  2. T. Bending Said,

    December 3, 2011 @ 4:14 pm

    I think you might also find that photos on the web which look fine on a Mac look dark on a PC? (something to do with ‘gamma’?)

  3. Tony Said,

    June 5, 2012 @ 2:51 pm

    The question isn’t whether your photos are too dark, the question is whether or not you like them.
    Tony

  4. Martin Lacey Said,

    June 16, 2012 @ 6:23 am

    Kieran,

    Can I start by saying that you’re a legend and your treated me royally at the Stumble Inn last night.

    With regard to the dark shots: Your camera is metering for the sky. It sees that it’s bright and it darkens the shot to try and get an average exposure. Three ways to fix it:
    1. If you’re using Canon: underexpose one stop on purpose by doing the following. Hold down the shutter button half way. Then while you’re holding tyhe shutter button down, move the dial on the back anti clock wise. That will reduce your exposure in 1/3 or 1/2 increments.
    2. Exposure the shot for the land by focusing on it, holding down the shutter button then recomposing for the shot you want while keeping the shutter button depressed half way. Press the shutter down fully to take the shot.
    3. Take the shot in RAW then drop the exposure in Lightroom/Adobe Camera Raw. The can drop by two stops and increase by 4 stops in Lightroom.

    Having said all that, the main problem is that he sky is 3 or 4 stops brighter than the land/water. So, you will either get the correct exposure for the land or the correct exposure for the sky, but not both. A way to counter this effect is to use a graduated neutral density filer (see http://www.bhphotovideo.com/c/buy/Graduated-Neutral-Density/ci/15073/N/4256189594). This will decrease the exposure of the sky while keeping the land/water the same. That’a how the pros do it.

    Cheers,
    Martin (Dub and concert photographer)

    http://www.martinlaceyphoto.com

  5. Martin Lacey Said,

    June 16, 2012 @ 6:30 am

    One other way. Set your camera to spot metering and take your exposure value off the land/water. Spot metering will take the exposure value from a small area in the image to you can be precise. Idea: Do an HDR shot ot he image. Her the sky and land dark and light then combine them in PS using HDR. You’ll get all exposure values for the image.

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