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50mm 1.8 focus problem

JacoMedia0113
Contributor

Whenever I focus automatically with the viewfinder, it doesnt actually focus where it says it will. For example, I tested this out with a roof and focused on the chimney and saw the red flashes indicating where the camera is focusing. It also looked perfectly in focus in the veiwfinder. When I took the shot and saw where the focus point was, it was about 10 feet closer to me than the chimney. Then I went to the lcd screen and focused the same way on the chimney and it focused perfectly. I tried this on other lenses and its only the canon 50 1.8. Its really not that expensive so I might get a new one or if you recommend a better 50mm lens. I use a canon 6d btw if that helps. Thanks.

32 REPLIES 32


@JacoMedia0113 wrote:

Whenever I focus automatically with the viewfinder, it doesnt actually focus where it says it will. For example, I tested this out with a roof and focused on the chimney and saw the red flashes indicating where the camera is focusing. It also looked perfectly in focus in the veiwfinder. When I took the shot and saw where the focus point was, it was about 10 feet closer to me than the chimney. Then I went to the lcd screen and focused the same way on the chimney and it focused perfectly. I tried this on other lenses and its only the canon 50 1.8. Its really not that expensive so I might get a new one or if you recommend a better 50mm lens. I use a canon 6d btw if that helps. Thanks.


Your lens is front-focusing. Fortunately, that can be corrected by an adjustment in your camera. Dig out or download the camera's instruction manual (making sure that it's not an abbreviated version) and read up on "autofocus microadjustment".

Bob
Philadelphia, Pennsylvania USA

Thanks for your feedback. Im hoping I wont have to take it in to be seen

What camera model?

John Hoffman
Conway, NH

1D X Mark III, Many lenses, Pixma PRO-100, Pixma TR8620a, LR Classic

A 6d

Then you can AFMA. If it was a Rebel you couldn't.

 

http://www.learn.usa.canon.com/resources/articles/2011/af_microadjustment_article.shtml

John Hoffman
Conway, NH

1D X Mark III, Many lenses, Pixma PRO-100, Pixma TR8620a, LR Classic


@jrhoffman75 wrote:

Then you can AFMA. If it was a Rebel you couldn't.

 

http://www.learn.usa.canon.com/resources/articles/2011/af_microadjustment_article.shtml


If it is an older EF 50mm f/1.8 and not an STM version, even AFMA may not help as those older lenses had inconsistant focus.

 

If you don't have the STM version spend the $90 and get one.

EF 50mm f/1.8 STM Refurbished

Yes its the stm. I would never put a bad set of glass in front of a 6d lol


@JacoMedia0113 wrote:

Yes its the stm. I would never put a bad set of glass in front of a 6d lol


I agree 10 feet is a lot, and would seem to indicate something other than a lens issue. But, if it is a lens issue it needs to be sent into Canon for repair.

 

Some things to eliminate on the use side.

 

Make sure you are in 'One shot' focus mode.

 

Make sure you are in single center AF point selection mode.

 

Do not use Auto AF point selection, AIServo or AIFocus for your test.

 

Here is a more recent and in my opinion better Microadjustment Guidebook.

 

Canon EOS AF Microadjustment Guidebook


@TTMartin wrote:

@JacoMedia0113 wrote:

Yes its the stm. I would never put a bad set of glass in front of a 6d lol


I agree 10 feet is a lot, and would seem to indicate something other than a lens issue. But, if it is a lens issue it needs to be sent into Canon for repair.

 

Some things to eliminate on the use side.

 

Make sure you are in 'One shot' focus mode.

 

Make sure you are in single center AF point selection mode.

 

Do not use Auto AF point selection, AIServo or AIFocus for your test.

 

Here is a more recent and in my opinion better Microadjustment Guidebook.

 

Canon EOS AF Microadjustment Guidebook


It's hard to see it as a lens issue. Note that the OP told us it focuses fine in live view, so the problem must be with the viewfinder's AF. AFMA should be the first thing to try.

Bob
Philadelphia, Pennsylvania USA
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