Why do I have to dial in AF micro adjustment now when previously I didn't need to?

Started Apr 26, 2013 | Discussions
Learnphotography
Forum MemberPosts: 56
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Why do I have to dial in AF micro adjustment now when previously I didn't need to?
Apr 26, 2013

Hi,

When I first bought my 6D + 16-35mm II five months ago, my AF micro-adjustment was Zero and spot on!

Today, I noticed that the lens back-focusing and have to dial in + 7 for both wide and telephoto ends. The result is spot on again with + 7. Every shots are now CONSISTENTLY spot on with +7, just like before.

What could have caused the change? Due to work commitment, my 6D and 16-35 have been sitting in dry cabinet mostly. There was no drop or knock. I did a firmware upgrade to 1.1.3 before I notice the problem but this has nothing to do with AF. This is quite worrying.

Canon EOS 6D
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Richard
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Re: Why do I have to dial in AF micro adjustment now when previously I didn't need to?
In reply to Learnphotography, Apr 26, 2013

There will be a slight drift in focus over time with any lens but I'm sure that time is greater than 5 months.

Has the ambient temperature change (given it's five months since you first checked AF)?

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meland
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Re: Why do I have to dial in AF micro adjustment now when previously I didn't need to?
In reply to Learnphotography, Apr 26, 2013

Learnphotography wrote:

Hi,

When I first bought my 6D + 16-35mm II five months ago, my AF micro-adjustment was Zero and spot on!

Today, I noticed that the lens back-focusing and have to dial in + 7 for both wide and telephoto ends. The result is spot on again with + 7. Every shots are now CONSISTENTLY spot on with +7, just like before.

What could have caused the change? Due to work commitment, my 6D and 16-35 have been sitting in dry cabinet mostly. There was no drop or knock. I did a firmware upgrade to 1.1.3 before I notice the problem but this has nothing to do with AF. This is quite worrying.

Are you sure your measurement method was exactly the same five months apart?

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JLim22
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Re: Why do I have to dial in AF micro adjustment now when previously I didn't need to?
In reply to Learnphotography, Apr 26, 2013

I recently noticed this also. When I purchased the 6D back in January, my 85 1.8 needed -18 in micro adjustment. Last week I noticed few shots were soft, so I did the test again and now it's perfect at -12. I used dot tune method to do micro adjustment.

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meland
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Re: Why do I have to dial in AF micro adjustment now when previously I didn't need to?
In reply to JLim22, Apr 26, 2013

JLim22 wrote:

I recently noticed this also. When I purchased the 6D back in January, my 85 1.8 needed -18 in micro adjustment. Last week I noticed few shots were soft, so I did the test again and now it's perfect at -12. I used dot tune method to do micro adjustment.

I'm not sure the dot tune method is really precise enough.

Try this - http://www.northlight-images.co.uk/article_pages/cameras/1ds3_af_micoadjustment.html

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