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Author Topic: lens calibration question  (Read 9766 times)

texshooter

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lens calibration question
« on: August 26, 2013, 11:49:41 am »

I'm calibrating my lenses with Focal Pro. If this software calculates an auto focus manual adjustment (AFMA) of say +5, should that AFMA be used when I take pictures by manually focusing through the view finder? Or is the AFMA only to be used when using the camera's auto focus system? My hunch is yes the AFMA is for manual viewfinder focusing as well as auto focusing,  but not sure.
« Last Edit: August 26, 2013, 11:51:36 am by texshooter »
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Bryan Conner

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Re: lens calibration question
« Reply #1 on: August 26, 2013, 12:39:10 pm »

The lens adjustments are for autofocus.  When you are in manual focus, YOU determine if it is in focus or not.  If you can not get the image in focus, then either there is something wrong with you or the lens....or you are too close to the subject etc.
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kaelaria

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Re: lens calibration question
« Reply #2 on: August 26, 2013, 12:52:27 pm »

It is for AF ONLY.  Not manual, not liveview.
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texshooter

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Re: lens calibration question
« Reply #3 on: August 26, 2013, 01:15:23 pm »

But if the lens is misaligned, I would think that manual focusing through the viewfinder would be impaired just as would be the auto focusing mechanism. But my camera does not have a manual focus manual adjustment (MFMA) control. It only has AFMA.  If the AFMA only fixes the auto focus mechanism, then using the term "lens calibration" is a misnomer.
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kaelaria

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Re: lens calibration question
« Reply #4 on: August 26, 2013, 02:35:01 pm »

You are completely misunderstanding the point.  It does NOT correct lens alignment.  It ADJUSTS for incorrect assessment by the AF system.
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texshooter

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Re: lens calibration question
« Reply #5 on: August 26, 2013, 03:13:06 pm »

You are completely misunderstanding the point.  It does NOT correct lens alignment.  It ADJUSTS for incorrect assessment by the AF system.

That may be true, but my confusion is justified because I read all over the web of folk who say they had to send their lens in to be fixed because the AFMA recommended by Focal or Lensalign exceeds +/-20 points. Sounds like they should be sending their camera body in to have the auto focus mechanism fixed instead of the lens.
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kaelaria

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Re: lens calibration question
« Reply #6 on: August 26, 2013, 03:15:49 pm »

True, and no one said otherwise.  That's why each lens/body combo is unique.  A lens get PHYSICALLY calibrated to neutral.  You are NOT calibrating your lens.  Good luck man...one day you'll 'get it' ;)
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AFairley

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Re: lens calibration question
« Reply #7 on: September 03, 2013, 06:07:48 pm »

That may be true, but my confusion is justified because I read all over the web of folk who say they had to send their lens in to be fixed because the AFMA recommended by Focal or Lensalign exceeds +/-20 points. Sounds like they should be sending their camera body in to have the auto focus mechanism fixed instead of the lens.

They should be sending in both.

The AFMA adjustment you make will not affect your manual focus if you use the ground glass of the camera viewfinder to achieve focus.
 
The AFMA adjustment will affect your manual focus if you are using the focus confirmation dot or some similiar visual indicator in the LED display in your camera viewfinder to achieve focus.
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kaelaria

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Re: lens calibration question
« Reply #8 on: September 04, 2013, 02:30:27 am »

The AFMA adjustment will affect your manual focus if you are using the focus confirmation dot or some similiar visual indicator in the LED display in your camera viewfinder to achieve focus.

That is NOT manual focusing.  That's like saying looking at the gear selection readout on your dashboard is manual shifting.  The autofocus confirmation displays have zero to do with manual focusing.  Manual is just that - manual.  You look through the viewfinder and judge for yourself what's in focus.  Nothing more period.
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AFairley

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Re: lens calibration question
« Reply #9 on: September 04, 2013, 01:20:07 pm »

That is NOT manual focusing.  That's like saying looking at the gear selection readout on your dashboard is manual shifting.  The autofocus confirmation displays have zero to do with manual focusing.  Manual is just that - manual.  You look through the viewfinder and judge for yourself what's in focus.  Nothing more period.

Actually, it is MANUAL focusing, because you are changing the focus point of the lens BY HAND.  I'll readily grant you that ground glass and AF system focus indicator are two completely different systems, that was not my point.
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