focus issue for my canon 7d and lens 70-200,2.8ll

sharagim1 · February 18, 2011

Hi everybody and i need your help
i bought my canon last years and after 1one month bought 70-200 2.8ll. it was perfect sharpness,
now since 2 moth ago when i take shot ,there is no more sharpness and it"s out of focus
and after change lens still samething,
i have 2 questions
1)how to find out my images is out of foucus? (how can i check it)]
2)how can i do micro adjustment for my 7d?
thanks for all response.

chrisjohnson · February 19, 2011

1) reset the camera (see manual). Then take a photo on automatic (green square setting). Hopefully it is now sharp.
2) micro adjustments are also described in the manual but I would not touch them until you solve question 1. When you want to check the micro focus, a simple way is take a blank sheet of A4 and use a pencil to draw a vertical and a horizontal line crossing in the middle. Now focus on the cross and do some pixel peeping to see where the lens is actually focussed.

ziggy53 · February 19, 2011

1) Basic AF accuracy is best accomplished using a flat target, i.e. a brick wall or other large textured surface. If a camera/lens cannot accomplish this task, it has no chance of passing any subsequent AF tests including real world use. Make sure that the target is at the typical distance for your normal use of the lens, meaning that a long focal length lens that you would normally use for wildlife at a distance should be tested at that same distance for AF accuracy. Always test a lens at least twice Minimum-Focus-Distance (MFD). Lenses rarely do their best at MFD (the exception being true "macro" lenses.)

If a lens shows consistent front or back focusing with the wall test, then use micro-focus adjust technique until you get consistent accuracy.

If the lens passes the wall test, proceed to the next test. If the lens fails the wall test and you cannot gain accurate AF with micro-adjust, send the lens back to where it came from or explore camera issues.

2) A fence line or similar, shot at an angle to the subject. Put a singular strong-contrast target on the top of the middle post and use a single focus point in the camera to focus against the target. This shows focus accuracy and/or how easily distracting for/aft objects influence AF accuracy (compared to the above wall shot). It also shows bokeh tendencies at different aperture settings.

3) A focus target/chart like in the following:

http://regex.info/blog/photo-tech/focus-chart

I do recommend testing these charts at twice minimum focus distance or greater. Most lenses, especially most zoom lenses, do not do their best at MFD. True macro lenses are the major exception.

4) A US stop sign, or similar very high contrast signage, both centered and off center and to the side and/or corner. This can show chromatic errors and off-axis errors.

5) A spectral highlight at night. (Point source ideally, but a street light at some distance will do.) Try to avoid "blooming" of the source but allow some white clipping. This shows internal reflections and dispersion problems. Again, test both in the center and with the subject at the sides or corners.

6) Now just shoot "typical" subjects for your use of the lens(es). It's important that the lens perform correctly for your intended uses.

sharagim1 · February 19, 2011

thanks guys for response.
i just wanted to say what"s right factoy camera setting for
Aut focus/ drive Af microadjustment:
0)disable
1)adjust all by same amount
2)adjust by lens

when this morning look at to my camera setting i saw its highlight it to adjust by lens

and i never adjust it by lens with microadjustment tools before,
any idea which one is the right setup?
thanks againg for response.

ziggy53 · February 19, 2011

First, disable the micro-adjust and then test the lens per my previous post. You should not use the micro-adjust unless you know that you have a problem.

sharagim1 · February 20, 2011

ziggy53 wrote: »

First, disable the micro-adjust and then test the lens per my previous post. You should not use the micro-adjust unless you know that you have a problem.

ziggy 53, you always trying to help me and other people ,which need it and response to us,
i just wanted to say realy apprectied.

sharagim1 · February 20, 2011

goldenballs wrote: »

1) reset the camera (see manual). Then take a photo on automatic (green square setting). Hopefully it is now sharp.
2) micro adjustments are also described in the manual but I would not touch them until you solve question 1. When you want to check the micro focus, a simple way is take a blank sheet of A4 and use a pencil to draw a vertical and a horizontal line crossing in the middle. Now focus on the cross and do some pixel peeping to see where the lens is actually focussed.

thanks for help.

holzphoto · February 20, 2011

you get the issue fixed?

i took my 800 out to photograph some hawks and every shot was blurry....got to looking and there was a smudge from my fingers on the front element, cleaned it and good as new.

sharagim1 · February 21, 2011

holzphoto wrote: »

you get the issue fixed?

i took my 800 out to photograph some hawks and every shot was blurry....got to looking and there was a smudge from my fingers on the front element, cleaned it and good as new.[/QUO
i did factroy defult and everything is fine, espicially auto focus.
thanks for help guys

john l · February 21, 2011

I hope you get it all sorted out. I also had a focusing problem with my 7d and 70-200 2.8 and sent it back to Canon. Both had focusing problems and $550. later I hope it is fixed. You live and learn. j

chrisjohnson · February 22, 2011

sharagim1 wrote: »

holzphoto wrote: »

you get the issue fixed?

i took my 800 out to photograph some hawks and every shot was blurry....got to looking and there was a smudge from my fingers on the front element, cleaned it and good as new.[/QUO
i did factroy defult and everything is fine, espicially auto focus.
thanks for help guys

I am glad my tip on resetting the camera worked. It did for me recently when my 40d/17-55 combo was playing up intermittently. My fingers are crossed that the problem does not return.

focus issue for my canon 7d and lens 70-200,2.8ll

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