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Author Topic: AF Adjustment : What Am i doing wrong!  (Read 3410 times)

paolotaverna

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AF Adjustment : What Am i doing wrong!
« on: May 10, 2013, 12:55:13 AM »

Good day, I am in the process of fine tuning my 1dx AF body and lenses combo with lensalign.  Naturally, I spent a lot of time aligning the red circle(making sure there is a same amount of white around...One Shot Focus, Normal Focus point).

Now, I am really stuck and don't know what to do in order to 1)Get good results 2) trust myself doing it

Mainly, with the lensalign on my combo 1dx + 50 F1.2, I found that AF needed -10 adjustment. 

PROBLEM is : When I take a photo of simple writting, it seems very very fuzzy...and if I take the photo with AF adjustment to 0...then I see good results

Here are all my files : https://www.dropbox.com/sh/98pv8euzc11l7xg/bF4X6vpYuk 

let me know if anyone can help.

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AF Adjustment : What Am i doing wrong!
« on: May 10, 2013, 12:55:13 AM »

neuroanatomist

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Re: AF Adjustment : What Am i doing wrong!
« Reply #1 on: May 10, 2013, 08:28:17 AM »
I have heard the 50L is difficult, and also it has focus shift (irrelevant if used wide open).  Also, distance has a big effect with that lens - an AFMA may be effective at the tested distance, but not appropriate at a closer distance.

What were your testing distances for the LensAlign and the paper?  How did you do the AFMA (number of shots, etc.)?
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jrista

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Re: AF Adjustment : What Am i doing wrong!
« Reply #2 on: May 10, 2013, 01:09:03 PM »

Good day, I am in the process of fine tuning my 1dx AF body and lenses combo with lensalign.  Naturally, I spent a lot of time aligning the red circle(making sure there is a same amount of white around...One Shot Focus, Normal Focus point).

Now, I am really stuck and don't know what to do in order to 1)Get good results 2) trust myself doing it

Mainly, with the lensalign on my combo 1dx + 50 F1.2, I found that AF needed -10 adjustment. 

PROBLEM is : When I take a photo of simple writting, it seems very very fuzzy...and if I take the photo with AF adjustment to 0...then I see good results

Here are all my files : https://www.dropbox.com/sh/98pv8euzc11l7xg/bF4X6vpYuk 

let me know if anyone can help.

It looks like your testing wide open. At maximum aperture, especially an aperture that wide, your going to experience some optical aberrations. Chromatic Aberration, Spherical Aberration, etc. Additionally, AFMA settings tend to be distance dependent. If you tune your AFMA for shooting at a distance of 40 feet, then start shooting at five feet....it is very likely your AFMA setting will not be ideal for the closer shots. If the lens works well at an AFMA setting of zero, I would leave it there, and stop down a third of a stop or so to sharpen things up at other distances.

paolotaverna

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Re: AF Adjustment : What Am i doing wrong!
« Reply #3 on: May 10, 2013, 02:04:52 PM »
Thank you guys

1- Distance:  I have tested at 3feet, 5 feet and approx 10 feet.  I did this because I know the 50L has some shifting issues at short distance.  B

2- Number of shots: Usually, My approach:  I take 2 shots at each AFMA for each distance let's say I start with at 10 feet:
1st iteration: -20, -15, -10, -5,0,5,10,15,20
Then I take a decision (on screen) for which I am going to dig deeper:  In this case, between -10 and -15. I restart the process and take 2 shots each
2nd iteration: -10,-11,-12,-13,-15
I decided to keep -10.

I seemed to have consistant results in terms of distance and repeatability.

Problem occured that when I had taken down the camera and take normal picture of writing...I notice the result is poor!

So this is why I do not know what is faulty !

again, I appreciate your help.

DJD

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Re: AF Adjustment : What Am i doing wrong!
« Reply #4 on: May 10, 2013, 03:47:45 PM »
What AFMA gives you the best looking pictures when you "take normal picture of writing"? This may sound silly but just use that setting.
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paolotaverna

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Re: AF Adjustment : What Am i doing wrong!
« Reply #5 on: May 10, 2013, 04:26:03 PM »
AFMA: 0 :-)

 What I will do now is maybe purchase FOCAL and see the results.

this  switch to Canon gear is more complicated that I would have expected !

JumboShrimp

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Re: AF Adjustment : What Am i doing wrong!
« Reply #6 on: May 11, 2013, 12:29:25 AM »
I had focus issues with my 5D and some old MF lenses, such as a Nikkor 55/1.2. After many failed attempts, I finally sent the body in to Canon. They (somehow) adjusted the body's focusing electronics, and the focus is much improved. You might consider this approach. Good luck.

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Re: AF Adjustment : What Am i doing wrong!
« Reply #6 on: May 11, 2013, 12:29:25 AM »

Skulker

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Re: AF Adjustment : What Am i doing wrong!
« Reply #7 on: May 11, 2013, 03:16:43 AM »
AFMA: 0 :-)

 What I will do now is maybe purchase FOCAL and see the results.

this  switch to Canon gear is more complicated that I would have expected !

If zero works I would stick with it. Simples  ;D why bother to make it difficult and worse? AFMA is there to fine tune if needed. Sounds very like you don't need it.
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Viggo

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Re: AF Adjustment : What Am i doing wrong!
« Reply #8 on: May 11, 2013, 04:29:04 AM »
Save yourself a lot of anger and frustration and get Focal right
Away. It gives me the accurate results I
Need. I use the 1dx with 50 L aaaaall the time. And after I bought the EC-s focusing screen it got even more fun.
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paolotaverna

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Re: AF Adjustment : What Am i doing wrong!
« Reply #9 on: May 11, 2013, 07:17:34 AM »
So did 3 tests with Focal and result was +3, + 2, +4(on 50L)
I've decide to make a 4th test and got +3...so +3 it is. (used strong Hallogen light to be EV 12)

after taking tests shots I am more confident the correction is accurate.  Although there is no true alignment with Focal...I still like it :-)

thx guys



jrista

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Re: AF Adjustment : What Am i doing wrong!
« Reply #10 on: May 11, 2013, 10:32:51 AM »
So did 3 tests with Focal and result was +3, + 2, +4(on 50L)
I've decide to make a 4th test and got +3...so +3 it is. (used strong Hallogen light to be EV 12)

after taking tests shots I am more confident the correction is accurate.  Although there is no true alignment with Focal...I still like it :-)

thx guys

Aye, FoCal is pretty good stuff. It DOES need a LOT of light to really work right, but it really simplifies an otherwise complicated process.

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Re: AF Adjustment : What Am i doing wrong!
« Reply #10 on: May 11, 2013, 10:32:51 AM »