Canon 70-200 IS II? Bad copies around?

[LongLensPhotography]

I nearly bought this drainpipe yesterday. It looked like new, etc. I did some quick sharpness tests. All was acceptable at 200mm f/2.8, but nothing exceptional at all, 70mm OK-ish, 120 - out of focus misery. I then popped on my f/4 IS and and it was like wiping a thick layer of lube off of the glass .
The other issue was IS. I couldn't get anything sharp at 1/25 and even had some blur at 1/100s. That is not a problem with 100L or that f4 IS.
Finally, if you focus at something close at 200mm and zoom out to 120mm does it still stay in focus?
Obviously I didn't buy it, but I wonder if this was a one off, or are they all like that should I try another one? If I managed to find a one actually good 135mm that could be an alternative.

Perhaps I will get 5D III first now.

 

[odd jim]

Even Canon L's are subject to the odd bad copy and mis matched calibration...

 

[LongLensPhotography]

Even Canon L's are subject to the odd bad copy and mis matched calibration...

There obviously are some. I am only trying to find out how much of a bad copy that one was before and if I try another

 

[TCR4x4]

There obviously are some. I am only trying to find out how much of a bad copy that one was before and if I try another

Not just sigma then ;-)

 

[MadWoman]

I bought mine last week and have been trying it out over the weekend. I honestly can't fault it - superbly sharp wide open, clear images at 1/6 sec with IS... I am blown away by the quality if it. The one you tried was very definitely atypical.

 

[andyred]

There obviously are some. I am only trying to find out how much of a bad copy that one was before and if I try another

It could have been dropped / caught against something, whilst not doing any visible damage, could have knocked it out inside ?

 

[LongLensPhotography]

I bought mine last week and have been trying it out over the weekend. I honestly can't fault it - superbly sharp wide open, clear images at 1/6 sec with IS... I am blown away by the quality if it. The one you tried was very definitely atypical.

nice to know Do you need to refocus if you zoom out? Well, you would refocus normally, but what if you shoot video for example?

 

[MadWoman]

There wasn't a change in focus that was visible through the viewfinder as I zoomed, but I always refocus as a matter of course, so there might have been a small change I couldn't see which would have been visible in the PC. Or there might not! Sorry!

 

[MadWoman]

Sorry, double post.