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Thread: Font and back focusing issue

  1. #1

    Default Font and back focusing issue

    1. Calibrate camera or lens?

    2. Off by how much then is consider an issue?

    3. Using Focus chart at 45degree vs 30degree, result is different, must die die use 45degree?

    4. Longer focal length tendency to back focus a bit?

    5. Calibrate by nikon need to pay how much? can take back within a day?

    thanks!
    D90|10-24mm f3.5-4.5G|70-300mm VR f/4.5-5.6G|18-105mm VR f/3.5-5.6G|35mm f/1.8|SB700|MB-D80

  2. #2
    Moderator daredevil123's Avatar
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    Default

    Quote Originally Posted by desertstrike
    1. Calibrate camera or lens?

    2. Off by how much then is consider an issue?

    3. Using Focus chart at 45degree vs 30degree, result is different, must die die use 45degree?

    4. Longer focal length tendency to back focus a bit?

    5. Calibrate by nikon need to pay how much? can take back within a day?

    thanks!
    1. Calibrate using AF fine-tune in your camera if only certain lenses give you problem. If AF fine tune is maxed out and still cannot fix the problem, then calibrate the lens. Same if your camera do not come with AF finetune capability. If all your lenses are off in the same direction, calibrate the mirror of your camera.

    2. That is up to your personal tolerances.

    3. 45 or 30 deg should still focus on the line ok. 45 deg will give you a more accurate reading of how much it is off by. And use a tripod when doing your tests and take note of the MFD of the lens.

    4. Focal length of lens has no relation to tendency for front or back focusing.

    5. You have to check with Nikon on costs and time required. Usually not within a day.
    Last edited by daredevil123; 22nd May 2011 at 07:42 PM.

  3. #3
    Senior Member Diavonex's Avatar
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    Default Re: Font and back focusing issue

    You may want to do a very simple test.

    1. Arrange 3 subjects at an angle to your camera

    2. Set aperture to the F1.8 or F2.8

    3. Focus on the middle subject

    4. The subject nearest and farthest from your camera should be blur

    See picture below




  4. #4

    Default Re: Font and back focusing issue

    Quote Originally Posted by daredevil123 View Post
    1. Calibrate using AF fine-tune in your camera if only certain lenses give you problem. If AF fine tune is maxed out and still cannot fix the problem, then calibrate the lens. Same if your camera do not come with AF finetune capability. If all your lenses are off in the same direction, calibrate the mirror of your camera.

    2. That is up to your personal tolerances.

    3. 45 or 30 deg should still focus on the line ok. 45 deg will give you a more accurate reading of how much it is off by. And use a tripod when doing your tests and take note of the MFD of the lens.

    4. Focal length of lens has no relation to tendency for front or back focusing.

    5. You have to check with Nikon on costs and time required. Usually not within a day.
    1. My camera dun have fine tuning, looks like got to calibrate on lens liao...

    3. Cos by using 45 degree, my lens are more accurate, if i drop to 30 degree or 20 degree, the focusing is off a bit more...

    4. icic (cos my 35mm is more to front focusing by 2mm, and 300mm is more to back focusing by 2mm also)...

    5. okie, thanks!
    D90|10-24mm f3.5-4.5G|70-300mm VR f/4.5-5.6G|18-105mm VR f/3.5-5.6G|35mm f/1.8|SB700|MB-D80

  5. #5

    Default Re: Font and back focusing issue

    Quote Originally Posted by Diavonex View Post
    You may want to do a very simple test.

    1. Arrange 3 subjects at an angle to your camera

    2. Set aperture to the F1.8 or F2.8

    3. Focus on the middle subject

    4. The subject nearest and farthest from your camera should be blur

    See picture below



    Hi, thanks for the suggestion!

    hmm.. i think mine is off by a bit only, so using this test, it still shows that it focus on the spot correctly...
    D90|10-24mm f3.5-4.5G|70-300mm VR f/4.5-5.6G|18-105mm VR f/3.5-5.6G|35mm f/1.8|SB700|MB-D80

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