# AFMA for new 135mm F2



## crandrewl (Oct 31, 2013)

Hi, I recently bought Canon 135mm F2 and I purchased FoCal Pro to do AFMA. I wasn't sure the correct target distance, so I tried two different distances. When I placed the target at around 5 ft, it gave me +6, but when I placed the target at around 10 ft, it gave me +12. Which setting do I pick? Is this normal to have different AFMA value depending on target distance? What is the correct target distance for 135mm lens when using FoCal? Thank you for your comments.


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## Mt Spokane Photography (Oct 31, 2013)

Typically, AFMA is done at 50 X the focal length. For a 135mm f/2, that comes to 22.1 ft. 

If you plan to use the lens at closer distances, then do the AFMA at the distance you use. Be aware that at close focus distances, its usually a different setting. 
If the AFMA value varies a lot with distance, you might want to send both your camera and the lens to Canon so they can calibrate both. They can adjust the lens at different distances so that the AFMA does not vary by more than about 5 points, likely less.


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## crandrewl (Oct 31, 2013)

Thank you for your reply. So it is normal to have different AFMA value depending on distance. 

How much variation do you consider too much that requires calibration? Is the lens / body calibration covered under warranty? Both my camera (6D) and the lens are still under warranty. 

By the way, 22 ft for target distance is too long for me right now because FoCal is on my desktop in my room. Maybe I should borrow a laptop to run FoCal outside so I can set the target at 22 ft.


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## Old Shooter (Oct 31, 2013)

AFMA can vary due to distance... Common recommendation is to check at 25X and 50X focal length... But what drives your AFMA decision is your use... If you bought it for headshots - then you probably want 25X... If you are going to shoot indoor sports - then maybe 50X is better...

My 135L required -4 at 4.3 meters on a 5DIII = Every camera/lens combo is different... I'm not sure how you got it to work at 5 feet - you got a green "check" at both normal and zoom settings? Both are required for FoCal to do its best for you...

Unless you are in a really big room, and can drench your target in light, I would put it on a laptop. Go outside, put that target in a bright location, get your camera on a sturdy tripod, and run FoCal again... Look at the "Result Confidence" and your test chart - make sure you got a good run... Hope this helps!


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## mackguyver (Oct 31, 2013)

My 135 f/2 was a mess and I would fail AFMA most of the time until I sent it to Canon for a calibration. After that, it was brilliant and I don't remember there being much of a difference between near and far results, but I'm not sure if I did multiple measurements. I typically AFMA with FoCal at the distance I plan to use it most using the model lights on my Paul C. Buff Einsteins. Remember, the brighter the target, the better. Also, doing a custom white balance in FoCal can give you better results, and I've found that Manual Mode works best with the 5DIII and other cameras that can't be automated.


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## surapon (Oct 31, 2013)

Dear, Sir, my Friends and Teachers.
Sorry, I ( My Brain) are low on High Tech/ Special Words in Photography. What is " AFMA ", and How can I use this Words/ Knowledge to improve my understand of My Love Hobby Photography?
Thanks you, Sir.
Sorry, I must ask you, If I do not Know or Do not understand.
Surapon


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## mackguyver (Oct 31, 2013)

surapon said:


> Dear, Sir, my Friends and Teachers.
> Sorry, I ( My Brain) are low on High Tech/ Special Words in Photography. What is " AFMA ", and How can I use this Words/ Knowledge to improve my understand of My Love Hobby Photography?
> Thanks you, Sir.
> Sorry, I must ask you, If I do not Know or Do not understand.
> Surapon


Autofocus microadjustment. Sorry for too many abbreviations/acronyms


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## surapon (Nov 1, 2013)

mackguyver said:


> surapon said:
> 
> 
> > Dear, Sir, my Friends and Teachers.
> ...



Thank you, Sir, Dear Teacher, Mr. mackguyver.
Ha, Ha, Ha, Sorry, Sir, I do it so many times, But forget this Short name " AFMA"
Have a great Night, Sir.
Surapon


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## Pi (Nov 1, 2013)

mackguyver said:


> My 135 f/2 was a mess and I would fail AFMA most of the time until I sent it to Canon for a calibration.



I had a similar experience, focus shift depending on the distance. I sent it to Canon and they fixed it.


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## Dukinald (Nov 1, 2013)

Old Shooter said:


> AFMA can vary due to distance... Common recommendation is to check at 25X and 50X focal length... But what drives your AFMA decision is your use... If you bought it for headshots - then you probably want 25X... If you are going to shoot indoor sports - then maybe 50X is better...



Slightly off topic. What is then the best distance to AFMA the 100L macro if it will be used as a macro lens 75% of the time and as portrait lens other times? (2500mm ~8ft)?

Using Reikan Focal for calibration. 
Thanks


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## neuroanatomist (Nov 1, 2013)

Dukinald said:


> Old Shooter said:
> 
> 
> > AFMA can vary due to distance... Common recommendation is to check at 25X and 50X focal length... But what drives your AFMA decision is your use... If you bought it for headshots - then you probably want 25X... If you are going to shoot indoor sports - then maybe 50X is better...
> ...



I tested mine at 50x and 25x focal length (as I do for all my lenses), and near the MFD (with the small printed FoCal target filling the frame). The values I got were +2, +4, and +3, respectively. I chose +3. 

I'd say test, and see what you get...


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## Mt Spokane Photography (Nov 1, 2013)

I tested mine at 6.8M (22.2 ft) and had a AFMA of -11. I use it at 20-40 ft, so that works for me. I tested all my lenses the day I got my 5D MK III, which is why the shutter count is 180.


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## CarlTN (Nov 1, 2013)

My 135 is +3 on my 6D, and was +2 on my 50D (if I recall correctly). It was like +13 on the 50D when combined with the 2X TC ii. It was and is, pretty much the same from .9 meters to infinity. At .9 meters it is barely a fraction of an inch off on the 6D.


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