Issue with 70-200 l F4 IS ?

[BTrigaux]

I have some doublts regarding the quality of my canon lens.


Context : used on 5D M2 (top class with 24-70 f2.8).


See 2 photos taken on tripod timer 2secs, zoom 200mm, iso 400,IS off. The images are viewed via DPP at 100% with AF set on central focus point.


Single difference : Photo 1 at f8 and photo 2 at f4. The quality difference (blur) between the two is so important compared to the results of different tests made with that lens (a.o. on this site).


Thanks for your opinion on this observation.





Bernard.


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[Sinh Nhut Nguyen]

How many images did you take with f/4 aperture? The second image seems out of focus to me.

[BTrigaux]

Several times tried.


How can I progress in my investigation ? Any hint ?

[neuroanatomist]

How can I progress in my investigation ? Any hint ?

First step is to test AF performance vs. lens performance. Take the shot at f/4 a couple of times with autofocus, and a couple of times with Live View, manually focusing at 10x magnification on the LCD. If it's sharp with Live View and not with AF, then you need to do an AF microadjustment. If you can't get a sharp image at the focus point with MF and Live View, it's likely the lens needs service.

[BTrigaux]

Thanks !


I will try this in the coming days.


Results will be shared here.

[BTrigaux]

Results of second round of tests following your recommendations :


Conditions of test :


- done on a stable tripod


- with timer set at 10 sec withou any wind


- IS off


- UV filter removed


- each setting tested 3 times


Very consistently same results as during 1st round both with AF and MF.


Now time to send it back for calibration.


Any idea about cost of such a service ?


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