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

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

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 Veteran Member • Posts: 4,117
Re: Why do I have to dial in AF micro adjustment now when previously I didn't need to?

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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Canon PowerShot G15 Canon EOS-1D Mark II Canon EOS-1D Mark III Canon EOS-1D Mark IV Canon EOS-1D X +6 more
(unknown member) Senior Member • Posts: 5,590
Re: Why do I have to dial in AF micro adjustment now when previously I didn't need to?

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?

JLim22 Regular Member • Posts: 495
Re: Why do I have to dial in AF micro adjustment now when previously I didn't need to?

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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Sony Alpha 7R II Sony FE 55mm F1.8 Sony FE 28mm F2 Sony FE 35mm F1.4 Zeiss Batis 85mm F1.8
(unknown member) Senior Member • Posts: 5,590
Re: Why do I have to dial in AF micro adjustment now when previously I didn't need to?

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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