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5d mark III front focus problem

mo
Apprentice

my 5d mark III has a problem with front focus. I use only crosstype focus points but even cental one can't focus correctly no matter what lens I use. the problem is more significant further the subjet focused on is. tried different light conditions with the same result. Camera always front focusing significantly, so the suject is out of DOF all the time. tested lenses 50/1.4 and 24-70/2.8 L. problem persist in all AI modes (focus/servo). please could you provide any solution? thanks in advance

18 REPLIES 18


Then that's another added feature of the 7D2. The 7D has only one setting per lens.

Bob
Boston, Massachusetts USA
 
Indeed it is, Bob, and it's surprising the difference with some lenses!!Cat Happy

KingEyre
Enthusiast

I suspect you're best to return for a calibration check at a Canon centre, I'm sure you'll be able to find out where that is from someone else here, I'm only aware of the UK one!

 

EDIT that was a reply to the OP!!


@KingEyre wrote:

I suspect you're best to return for a calibration check at a Canon centre, I'm sure you'll be able to find out where that is from someone else here, I'm only aware of the UK one!

 

EDIT that was a reply to the OP!!


Yeah, I figured that.  Smiley Happy

 

There are at least four Canon repair centers in the US. The one in Jamesburg, New Jersey is particularly convenient for me, since it's only a couple of miles from the route I use to visit my daughter in Philadelphia. Others are at Norfolk, Virginia, Chicago, Illinois, and somewhere in southern California.

Bob
Philadelphia, Pennsylvania USA

Bob from Boston,

 

I can read the Canon manual!  Unusual?

 

1. Mount the camera and lens on a tripod. If the lens has
IS, shut it off.
2. Use Live View to manually focus on a stationary,
flat, high-contrast object that is at the center of the
viewfinder and parallel to the plane of focus. The
camera-to-subject distance should be no less than 50
times the focal length of the lens. For a 50mm lens this
would be at least 2.5 meters, or approximately 8.2 feet.
3. Focus the lens at its maximum aperture. Use Live View
magnification if necessary to assure that the image is
as sharp as possible.
4. Without touching the focusing ring or moving the tripod,
turn off Live View, and return the camera to One-Shot
AF, using only the center AF point.
5. Gently press the shutter button down halfway (or the
AF button if using back-button AF) while observing the
focusing ring or scale on the lens. It should not move.
If it does, take note of whether AF moves the plane of
focus closer (front-focus) or further away (back-focus).
If there is no shift in focus your lens is well-calibrated
and requires no adjustment.
6. To determine the correct amount of adjustment
necessary, take three sets of images at microadjustment
settings of -10 , 0 and +10; in other words,
three consecutive images at -10, three consecutive
images at 0, and three consecutive images at +10.
7. Examine the resulting images on your computer
monitor at 100% pixel magnification.
8. Take additional sets of test images at different
microadjustment settings if necessary until you can
determine which setting produces the sharpest image.
9. Register the corresponding microadjustment setting in
the camera.

 

Also, IMHO, what is thought to be miss-focus is actually user error and not camera/lens.

EB
EOS 1DX and 1D Mk IV and less lenses then before!


@ebiggs1 wrote:

Bob from Boston,

 

I can read the Canon manual!  Unusual?

 

1. Mount the camera and lens on a tripod. If the lens has
IS, shut it off.
2. Use Live View to manually focus on a stationary,
flat, high-contrast object that is at the center of the
viewfinder and parallel to the plane of focus. The
camera-to-subject distance should be no less than 50
times the focal length of the lens. For a 50mm lens this
would be at least 2.5 meters, or approximately 8.2 feet.
3. Focus the lens at its maximum aperture. Use Live View
magnification if necessary to assure that the image is
as sharp as possible.
4. Without touching the focusing ring or moving the tripod,
turn off Live View, and return the camera to One-Shot
AF, using only the center AF point.
5. Gently press the shutter button down halfway (or the
AF button if using back-button AF) while observing the
focusing ring or scale on the lens. It should not move.
If it does, take note of whether AF moves the plane of
focus closer (front-focus) or further away (back-focus).
If there is no shift in focus your lens is well-calibrated
and requires no adjustment.
6. To determine the correct amount of adjustment
necessary, take three sets of images at microadjustment
settings of -10 , 0 and +10; in other words,
three consecutive images at -10, three consecutive
images at 0, and three consecutive images at +10.
7. Examine the resulting images on your computer
monitor at 100% pixel magnification.
8. Take additional sets of test images at different
microadjustment settings if necessary until you can
determine which setting produces the sharpest image.
9. Register the corresponding microadjustment setting in
the camera.

 

Also, IMHO, what is thought to be miss-focus is actually user error and not camera/lens.


Ah, the "camera-to-subject distance". That's a welcome clarification. I don't believe you used that term in your earlier post.

Bob
Philadelphia, Pennsylvania USA

"If you do decide to do MFA, make sure you are not real close to 'close focus' of the lens.  Usually, 50 times the focal length of the lens is the rule."

 

Hmmmmm...?  OK.  Smiley Frustrated

 

BTW, off subject, a little, do you know Click and Clack, from Harvard Square?

EB
EOS 1DX and 1D Mk IV and less lenses then before!


@ebiggs1 wrote:

"If you do decide to do MFA, make sure you are not real close to 'close focus' of the lens.  Usually, 50 times the focal length of the lens is the rule."

 

Hmmmmm...?  OK.  Smiley Frustrated

 

Well, I said I wasn't clear about what "real close to close focus" meant. Could have been an actual distance in feet or a point on the focusing ring.

 

BTW, off subject, a little, do you know Click and Clack, from Harvard Square?


I've listened to their program quite a few times, but I never met them. One of them (I forget which one) died this past year.

 

BTW, in this part of the world, MFA means "Museum of Fine Arts".  Smiley Wink

Bob
Philadelphia, Pennsylvania USA

Tom

EB
EOS 1DX and 1D Mk IV and less lenses then before!

mo
Apprentice

thanks for all your comments, I'm gonna run the tests again as I was advised here and decide what options do I have.

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