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Thread: micro focus adjustment w/ LED lighting

  1. #1
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    micro focus adjustment w/ LED lighting

    I have a 6D, 24-105 F/4 IS lens and am considering using Reikan Technologies FoCal to calibrate the combination. I recently upgraded our home to LED lighting. Is this is going to be an issue? If so, is it practical perform the calibration outside in the natural sunlight?
    Thanks.

    Answering my own question: Yes, natural sunlight is the recommended way to perform the calibration.

    Last edited by gschaps; 10-10-2013 at 03:59 PM.

  2. #2
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    Not sure how much sunlight you have where you live. Tuning in AFMA works best when you have a lot of light (Reikan will tell you if you have sufficient levels, they recommend 10+ EV, iirc).

    I got two 250W work lights similar to these: http://www.homedepot.com/p/Designers...p#.UlbfGxa9WmQ

    Not expensive, just make sure they have halogen bulbs, and with 500W total or more you should be fine.
    Arnt

  3. #3
    Senior Member neuroanatomist's Avatar
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    I use halogen lighting, since I can't always count on natural light. Even when I'm shooting outdoors because I'm calibrating a lens >300mm, I still run an extension cord and add some light to the sun. I like my Ev readings to be in the 11-14 range.

  4. #4
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    How often do you adjust a camera/lens combination? The 6D manual says you should do it on site, which leads me to believe often. Thanks.
    Last edited by gschaps; 10-12-2013 at 08:21 PM.

  5. #5
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    Just because the manual lists something as ideal, it doesn't mean it's practical. The manual also says the operating temperature should be above 0°C, but I've seen and taken many photos in the snow. It would serve us better if they listed WHY you should recalibrate in a new location... type of light, temperature changes, setting up on the actual focal length you're going to use, all of the above. The fact that it's new, and auto focus is old, means it's not really very necessary to recalibrate, or would have all been complaining about AF accuracy for years.
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  6. #6
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    Agree with David.....when you travel or set up in a new or different environment you can take a few shots and do some pixel peeping to see if an AF adjustment is needed. I don't perform a microadjustment at any specific time intervals. I have left mine alone for more than a year with no issues but I am not moving in and out of extreme environments

  7. #7
    Senior Member neuroanatomist's Avatar
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    Quote Originally Posted by gschaps View Post
    How often do you adjust a camera/lens combination? The 6D manual says you should do it on site, which leads me to believe often. Thanks.
    Not often. The reason for the 'on site' recommendation is that AFMA is distance-dependent. Many times, what works at 25-50x the focal length (recommended calibration distance) doesn't apply with very close subjects.

    I calibrate each new lens on each body when I get it (and all lenses to a new body). I test them again every 6-9 months, but they're stable (unless you drop your camera - I did that to my 5DII, 3' to pavement, not a scratch the body worked perfectly, but all my AFMA values shifted ~10 units to the negative relative to the original values).

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