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next PZ lens test report: Canon EF 24-70mm f/4 USM L IS (on APS-C)
I can't see the link on the main page?......

Quote:Crystal ball stuff-

Do you think RSA issue likely in all copies, at least to some build date?

Is Canon likely to correct issue, or is it destine to be forever 'feature'?


(EOS newbie with no EOS glass between 22 and 70mm.)

It was a problem on two samples. The rest is speculative.
hmmm, I thought there was another post or three :-) re. this lens, but as I can't see anywhere else to post this, my final update, on this lens I'll post it here if I may....


<p style="font-size:12px;font-family:Helvetica;">- this lens (+ camera) was checked and adjusted by Canon at North Ryde (a nice spot they have up there btw) and I picked it up after 6  days - on a quick check (but not going to the beach and counting every grain of sand :-) the micro focus setting for best auto-focus is now consistent throughout the lens range, i.e.. just like every other lens I have, so this is a good thing and I'm happy :-) - ta all, sorry to have been a bother.... :ph34r:....

I have added a note to the two reviews that Canon may be able to fix the issue. If so the optical rating would increase by 1*.

I don't get it, it seems like you guys talk about separate issues? SoLong seems to talk about focus inaccuracy, which MFA would overcome, and the service center has more or less rectified. But Klaus was talking about focus shifts.


Can you give a clear explanation? 

Well, a focus shift can also be adjusted via correction factors in the AF.

Pentax is doing so for ages I think.

This wouldn't help with MF though.



I just got this lens and I really like really well so far for me. Only problem I see that is bothersome is that at close focusing distances (<2ft) at 70mm the resolution is VERY poor. You showed this basic effect in your image where you showed your copy's focus shift issue. However, I am wondering more about this softness at close focus distances. On my lens, if I change it to the start of macro mode, I can focus still out towards infinity, but the close focus issue is fixed when I do this and take the picture from the exact same distance. It goes from being very soft to sharp! This effect goes away with subjects about three feet away. Did both your copies do this? Can you explain this behavior?


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