Calibrating a digital SLR

Discussion in 'Nikon' started by raymondc, Dec 10, 2007.

  1. Hi, just a general question. Done some readings and it talked about calibrating
    a DSLR with a gregtag macbeth color chart.

    Is this method only viable in a studio where the lighting is consistent?

    If I calibrated this say indoors at home, and then go overseas on holiday and
    stuff, can I still use that calibration? Or does it mean, I have to shoot a
    color chart at each diff location I am in?

  2. Ray why do you need a calibration? What is your camera? I am not an expert on this but the experts will want to know :)

    A calibration only gives you an improvement over the calibration "as is" if the calibration is better than the one you got. It is very easy to screw up the calibration. When done correctly it is very likely that there is only a noticeable improvement for one light setup , e.g. for a studio with a certain defined set of lights. Depending on the individual sensor a careful calibration would be beneficial for all shooting but there is more needed than to put a test chart on the table and take few pictures.
  3. Calibrating your camera?

    Usually you calibrate your monitor and if you print at home, your printer. Not your camera.

    For optimal color, you should shoot a color chart at every location you shoot to get accurate color. (accurate color is not always best).

    The reason you calibrate you monitor is so what you see on your computer is what everyone else will see and get the "true" color of the image. You calibrate your printer so you are printing what you see.

    With all that said, if you insist on shooting jpeg there are in-camera settings that you can do to "tweak" the out of the camera image.
  4. You can do this but you have to calibrate for a huge variety of color temp light sources so I've never felt it was worth the hassle. I believe where this is often done is for product photography under studio lighting, a great deal of time and work is done to ensure that that jacket color is as close as possible to the actual item to stop a flood of returns.
    I've found that if I get the white balance correct, I shoot a whibal card and use that to set my color temp in lightroom or ACR, the image color is close enough for me.
  5. Adobe Photoshop and Lightroom RAW converters have a calibrate tab. You can calibrate the RAW converter to your specific camera so you get more accurate color when using the RAW converter. This calibration requires a RAW file of the GregTag Macbeth color checker and several scripts are available you can use with Photoshop to generate the calibration numbers. I have calibrated the RAW converter for my camera using this approach and it imporves the color accuracy.

    You can find a lot of information at this site:

    This calibration is valid for all conditions. You have to make sure you get a good image of the color tartet - exposure, even light, etc. I use direct sunlight for this image.
  6. I would think that you need to do this calibration specifically for each light that you're working under. The results would be interesting of course. But most people are happy working with what their raw converter gives for colors.
  7. And if you turn your camera significantly around from your first calibration, please
    recalibrate and the subject will be gone....

    Of course if you take the same shot repeatedly, as in a passport picture studio, calibrate
    once and make sure the voltage changes during the day do NOT affect your color
    temperature ... So it would be wise to monitor line voltage and recalibrate every 10
    minutes to get it perfect.

    See where this leads: utter nonsense, I am afraid you are afraid too much ...
  8. If you shoot in the RAW mode, white balance may be changed at any time without damaging the original file. This is sufficient most of the time, since you can fine-tune the white balance and other conversion factors in Adobe Camera Raw (or other RAW converters).

    The next step up is to use a white or grey card and the camera menu to "calibrate" the white balance for a particular lighting source or environment. This is basically a red/blue balance, and is applied in-camera.

    The ultimate "calibration" is to use a Color Checker chart (Gretag-MacBeth) or IT8 chart. Shoot an image of the chart in the same light as your subject and create an ICC profile using Eye-One software or the Pictocolor plug-in "InCamera". This creates R, G, and B correction curves throughout the entire luminance range - the more patches the better. You get daylight rendition with practically any studio lighting source.

    I believe Nikon Capture can load an ICC profile into the camera, but the best way is to use the profile in Photoshop - "Assign" the profile, then "Convert" to a standard color space.
  9. There's also a cheap way to calibrate a DSLR, if you are using PS ACR.

    Print out a target with various color patches. (I used my inkjet to print the widest gamut r,g,b,c,y,m,k and purple on matte paper.)

    Get a Solux lamp, and photograph the target -at your workstation-, lit only by the Solux. Leave the target lit by the Solux, and bring your RAW image into ACR.

    You can view the target, and ACR at the same time

    Tweak ACR's calibrate tab. I found I needed to reduce g and b saturation, and slightly tweak their hue.

    Regarding the Solux products- I like the bulbs, but the fixtures are over priced. You should be able to find something locally.

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