Beware - focus problem with Canon 17-55mm lens

I should mention, some say other Canon lenses also show AF problems.
That could be, but I have not observed that. I own 6 other Canon
lenses, and none of them show this AF problem, only my 17-55mm lens
does.


On Wed, 06 May 2015 01:06:27 -0600, Wally wrote:

The much-praised Canon 17-55mm/2.8 lens shows variable autofocus
problems when the focus target is in the distance (a city block or so,
or farther). This makes the lens a poor choice for general purpose
photography.

The effect is often missed because users tend to stop the lens down
when shooting outdoors, increasing the DOF to the point that the
distant subject is sufficiently sharp. But when users open up. the
distant subject can go blurry, with the focal plane falling in the
foreground.

The error seems to occur all the time when focusing into the distance
in susceptible systems, but the extent of the error varies randomly.
Sometimes you will get three or four sharp pictures, followed by a few
very blurry results, all taken with the same settings. In my own
experience using the lens with my 7D Mark II, about 2/3 of the results
are unacceptable when shooting at f/2.8. I also get failures at f/5.6
and other apertures.

My lens has shown this autofocus failure on my 40D, XSi, 7D, and now
on the 7D2. I have six other Canon lenses, and they all focus fine. So
I conclude it is not the body, but the lens.

The AF failure never occurs indoors where distances are shorter. And
the failure never occurs in live view, whether I am shooting short or
long distances.

The lens has been to Canon service five times. Each time, they say the
lens meets all specifications. And each time, the AF failures
continue.

Recently I have had an opportunity to test a second copy of the lens,
and it behaves exactly the same as my lens. I can't say for sure, but
I think all copies have this fault.

Some users get consistent sharp results with this lens, though. It
seems that the body used affects the behavior. I have found that the
lens almost always gives sharp results on my Rebel SL1. Others report
that good results are obtained on the 7D, but not the 7D2.

The focus issue with this lens is very poorly documented on the Web,
but a search in Google will turn up some instances.

If you are in the market for the Canon 17-55mm lens, and if the
distant-focus issue is a concern of yours, I suggest you test the lens
carefully with your body during the dealer's return period to
determine if the lens is satisfactory for your intended use.

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On Thu, 07 May 2015 18:43:35 +0200, android wrote:

In article ,
Wally wrote:

On Thu, 07 May 2015 08:47:01 +0200, android wrote:

In article ,
Wally wrote:

On Thu, 07 May 2015 04:54:08 +0200, android wrote:

In article ,
Wally wrote:

On Wed, 6 May 2015 10:02:29 +0200 (CEST), android
wrote:

Wally Wrote in message:
The much-praised Canon 17-55mm/2.8 lens shows variable autofocus
problems when the focus target is in the distance (a city block or
so,
or farther). This makes the lens a poor choice for general purpose
photography.

https://duckduckgo.com/?q=micro+focus+adjust

HTH, or something...

Good luck with fixing a variable focus problem with MFA.

I don't own that lens but if I had that problem then I would give those
links a good shoot! It is a fast lense in it's class and those might
benefit from MFA, if available.

Nonsense. Variable focus errors can't be fixed by MFA.

Assuming that that is your problem...

No assumption necessary

I would give it a try, if I were you...

Yes, thanks, already did that, without succes.

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