April 18, 2014, 03:15:16 AM

Author Topic: AFMA – Easy or Not  (Read 3344 times)

LetTheRightLensIn

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Re: AFMA – Easy or Not
« Reply #15 on: March 23, 2013, 02:47:26 AM »
Just want to add something that hasn't been discussed before: it is pointless to do microadjust zoom lenses (unless you have the latest models that actually allow to do that) - the amount of correction you will need for smallest/largest focal lengths will be different.

Not necessarily at all. So far for all of my L zooms and my tamron zooms it's been nearly the same value needed at either end, although for one canon non-L it was problematic with the older MFA system since the ends were very different, but I could at least fix one end on the spot to get by in the meantime.

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Re: AFMA – Easy or Not
« Reply #15 on: March 23, 2013, 02:47:26 AM »


digital paradise

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Re: AFMA – Easy or Not
« Reply #17 on: March 23, 2013, 09:51:54 AM »
hard...

I guess I could have been less winded and just said that  ;D

Zen

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Re: AFMA – Easy or Not
« Reply #18 on: March 23, 2013, 01:54:30 PM »
According to DotTune, my 24-70 2.8 II is spot on at 0!

I've checked all my lenses and all are quite acceptable. Don't understand why others have so much trouble!

Maybe my standards are lower??

Z

Mt Spokane Photography

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Re: AFMA – Easy or Not
« Reply #19 on: March 23, 2013, 02:19:49 PM »
Just want to add something that hasn't been discussed before: it is pointless to do microadjust zoom lenses (unless you have the latest models that actually allow to do that) - the amount of correction you will need for smallest/largest focal lengths will be different.
I have found only a small difference in AFMA between wide and zoom for most of my lenses.  Picking a mid point, or for a lens like my 100-400mmL, the long end works fine.  Its far better than having all focal lengths be off.
 
Here are some results of my tests for my zoom lenses. 
 
 
Canon 24-105mm L                     
 
                                    24mm            +0       
 
                                    50mm            -3       
 
                                    105mm         -2       
 
Canon 70-200mm f/4L IS                       
 
                                    70mm            -5           
 
                                    100mm         -3
 
                                    200mm         -3
 

 
 

TrumpetPower!

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Re: AFMA – Easy or Not
« Reply #20 on: March 23, 2013, 03:24:04 PM »
I have found only a small difference in AFMA between wide and zoom for most of my lenses.

It's also worth noting that the difference you found  is small enough that it's well within the margin of error. That is, on any given shot, the AF system itself is going to vary by at least +/- 1, which is the difference you list for your lenses.

Personally, with your findings, if I could only have one adjustment (rather than the two you get with modern bodies and zooms), I'd split the figures and forget about it.

That's a great thing about FoCal -- it plots the results. And you can plainly see that pretty much any number in that plateau area is going to produce the same real-world results -- and that sweating over neighboring values in the middle of the sweet spot is an exercise in futility.

Cheers,

b&

RGF

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Re: AFMA – Easy or Not
« Reply #21 on: March 23, 2013, 05:23:30 PM »

 Actually I read that Canon delayed the release to insure the it's  manufacturing was dialled in properly.           

Canon is doing something differently now versus 10 years ago.  Remember eye control, DO, EOS 1N RS, ...

All one offs or never made it into the main stream.  Seems that Canon had been for years sell prototype technologies to see if they ever caught on.

Ever since Canon got burnt by the bad AF on the 1D M3 they seem to be spending more time to make sure things are more solid.  Also they have upped their prices so I suspect they feel the need to deliver more value.

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Re: AFMA – Easy or Not
« Reply #21 on: March 23, 2013, 05:23:30 PM »

digital paradise

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Re: AFMA – Easy or Not
« Reply #22 on: March 23, 2013, 11:31:37 PM »
According to DotTune, my 24-70 2.8 II is spot on at 0!

I've checked all my lenses and all are quite acceptable. Don't understand why others have so much trouble!

Maybe my standards are lower??

Z

Mine was - 1@ 24 and +1 @ 70. Maybe I should send it in  :D   

Sella174

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Re: AFMA – Easy or Not
« Reply #23 on: March 25, 2013, 09:11:47 AM »
I never knew my EF 50mm f/1.4 USM lens front-focused, until the chap I sold it to showed me ... he was shooting "portraits" at f/1.4 ... I always used it at f/8~11.
Sold most of my Canon gear ... here's what's left: EOS 30D (x2), EF 24mm f/2.8, EF Compact-Macro 50mm f/2.5, EF 70-200mm f/4L USM.

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Re: AFMA – Easy or Not
« Reply #23 on: March 25, 2013, 09:11:47 AM »