# Calibrate Canon 24-70L?



## killswitch (Oct 10, 2012)

I just wanted to know how I can calibrate the AF of my Canon 24-70L when mounted on a Canon 60D. Since there is no AFMA in the 60D does that mean my only resolution is to send it to Canon and have them take a look at it? Also, I dont know if its really an AF issue, it's known to be soft at f2.8 but when set to f5.6 or above it starts to become sharper but still not quite as sharp as I was hoping an expensive lens like this to be. Is this really a known property of this lens? You know, being a little soft.


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## neuroanatomist (Oct 10, 2012)

killswitch said:


> Since there is no AFMA in the 60D does that mean my only resolution is to send it to Canon and have them take a look at it?



Yes, that's really the only option. You would probably need to send both camera and lens.



killswitch said:


> Also, I dont know if its really an AF issue, it's known to be soft at f2.8 but when set to f5.6 or above it starts to become sharper but still not quite as sharp as I was hoping an expensive lens like this to be.



Possibly two things going on - almost all lenses get sharper when stopped down, but the deeper DoF of the narrower aperture also masks AF errors.

Try the following - lens on a tripod, set f/5.6, pick a subject with good contrast for the AF system and detail at multiple distances. Take a few of shots with the regular AF (mirror lockup, self timer), then take a few shots of the same scene with Live View (not the quick AF where the mirror flips up, but the contrast AF). If the shots with Live View look sharper that those using phase detect AF, that would be something that AFMA could correct if you had it, and a trip to Canon is needed since you don't.


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## Dylan777 (Oct 10, 2012)

Could be the the lens itself. In the past, I bought 3 copies of mrk I and all 3 were soft at 2.8.

60D doesn't have built-in AFMA, I'm not sure you can do it yourself.


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## Mt Spokane Photography (Oct 10, 2012)

Sit the camera on a tripod and aim it at a brick wall 15 feet more or less away. Make sure it is perpendicular to the wall.

Use live autofocus (not quick AF). This will focus the lens according to the highest contrast at the selected AF point. 

If its sharp, it needs AFcalibration. If its sharplly focused in the center but not at the edges, thats normal since the lens has a large field of curvature.
If the lens is still not sharp when focused this way, it has more serious issues that Canon might be able to resolve. I've had five of them, on a crop camera, they were not excellent, but they were adequate..


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## killswitch (Oct 11, 2012)

Thanks guys, I will check out the test you fine folks suggested and will post back here!


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## killswitch (Oct 11, 2012)

Ok, so here it is. I haven't gotten around shooting at a brick wall yet. But I think I will throw in more tests. This is what I did

1) mounted on a tripod, 70mm, set to AV priority, @5.6, ISO 100, AWB. Center focus point selected. Shot in a living room at night.

2) shot normally (2 sec timer, mirror lockup enabled) @ 5.6 aperture

3) live view (2 sec timer, AF Live) @ 5.6 aperture

If I did this right, then OMG. The shots from AF Live, is way sharper then normal Phase detect AF. I am including the full shot and a 100% crop of the top part of the book.


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## killswitch (Oct 11, 2012)

100% crop


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## kalmiya (Oct 11, 2012)

killswitch said:


> I just wanted to know how I can calibrate the AF of my Canon 24-70L when mounted on a Canon 60D. Since there is no AFMA in the 60D does that mean my only resolution is to send it to Canon and have them take a look at it? Also, I dont know if its really an AF issue, it's known to be soft at f2.8 but when set to f5.6 or above it starts to become sharper but still not quite as sharp as I was hoping an expensive lens like this to be. Is this really a known property of this lens? You know, being a little soft.


I let my 24-70 be calibrated in a canon authorized service center (there's a website which will list you where they are in your country, in the Netherlands there are only 2, so it took a 1h drive : )

Anyway, the body (550D) still fell under warranty, so calibration was for free... Made an appointment, gave them body + lens, waited for 30 minutes and got everything back calibrated. Great service.


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## Mt Spokane Photography (Oct 11, 2012)

killswitch said:


> Ok, so here it is. I haven't gotten around shooting at a brick wall yet. But I think I will throw in more tests. This is what I did
> 
> 1) mounted on a tripod, 70mm, set to AV priority, @5.6, ISO 100, AWB. Center focus point selected. Shot in a living room at night.
> 
> ...


In that case, get it calibrated, or, if you cannot get it done free, consider selling the 60D and get a 7D and do it yourself. You will then be able to use the AFMA for all your lenses. You might be pleased at the difference.


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## neuroanatomist (Oct 11, 2012)

killswitch said:


> The shots from AF Live, is way sharper then normal Phase detect AF.



A textbook case of the need for AFMA.


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## Dylan777 (Oct 11, 2012)

Don't forget to send both: body and lens


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## jasonFTW (Oct 11, 2012)

While I agree that you most likely need things adjusted by Canon, using AV mode may not yield the exact same shutter speeds. Tripod, mirror lock up and 2 second timer definitely helps, but shooting in manual with your aperture and shutter speed locked in should guarantee you are looking at the exact same exposure.


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