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Old Dec 10, 2014, 11:22 AM   #1
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Default SpyderLensCal Focus Aid

Anyone ever use this to calibrate your lenses? Any other suggestions on lens calibration would be appreciated. Thanks
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Old Dec 10, 2014, 9:32 PM   #2
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Phase detect auto focus can be adjusted, the contrast detect auto focus when using live view can't. live view AF is the most accurate. I shoot 2 images one using each type of AF then use the menu to adjust AF (phase detect) to match the live view focus, assuming they didn't match.
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Old Dec 11, 2014, 12:06 AM   #3
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How do you determine back or front focus? Do use a focus chart?
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Old Dec 11, 2014, 2:02 PM   #4
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I assume that the contrast detect image shot using Live View is as good as the lens can do because it uses the image projected directly to the sensor. If the live view is sharper than the phase detect image I try a little trial and error trying to match the sharpness of the live view image with additional images shot using phase detect altering the focus adjust +/-. I normally will put the camera on a tripod turn off SR and shoot identical images using the 2 focus methods. I will normally shoot several images using LV and chose the best, same with Phase detect. The same would work using a focus chart again using Phase detect as the base for the lens, but with an angled focus chart you would know if the camera is front to back focusing. The Phase detect process requires tight tolerances in the manufacturing of the camera and can result is some tradeoffs thus requiring focus adjustment.
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...It is better to burn a roll of film than curse the darkness. Equip. K30, Q7, DAL 55-300, DA 35 f2.4, DA 50 f1.8 DA 18-135, SMC-M 28 f3.5, SMC M 50 f1.4, Canon P&S S100 w/CHDK Beta, Panasonic DMC-GM5, Flickr:

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Old Dec 11, 2014, 4:52 PM   #5
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Thanks for the explanation-will try it this weekend.
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Old Dec 18, 2014, 4:58 AM   #6
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back or front focus will occur the same with live view than photographing through the finder. It's something that occurs with each lens and camera combination.

I calibrate myself with the spyderlenscal two to three times a year. Depending on how much I use a lens.
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Old Dec 18, 2014, 10:49 AM   #7
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Thanks-based on the limited info I have read it appears that the situation occurs because of the DSLR mirror configuration in combination with each lens. Read that the new mirrorless camera's eliminate the focus problem-will look into that.
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