From: jj on
Can someone (anyone!) with first-hand experience with the Canon
24-70L f2.8 USM please comment on the issues I keep hearing about? I
know they're sharp, and that the 28-70L is old, etc, but there seems
to be issues with these newer lenses.

I rented a 24-70L from a very reputable shop after my 28-70L was
stolen. Now, especially after reading various comments online, I can't
decide if I really want to buy one or look for a good used 28-70L.

First of all, when I cranked the lens all the way open to 24mm, it
"locked up" there. Like there's a light notch in the barrel that
intentionally holds it at 24mm. Where my 28-70 was free-flowing and
smooth from start to finish, the 24-70 required an annoying "unclick"
effort to get it back out of the "notch" position.

In what may be related, I've read several reports about the zoomring.
A poster wrote on another forum: "Defective or not: it's important.
The zoomring issue returns in several forum topics. I had the same
feeling, and mine is in now because something probably broke off after
extensive use. It's in for repair now."

Anyone else experiencing this stuff? Did Canon design it that way or
did I get a bad lens?

Next off, while it worked fine with available light, on at least 31
frames with this lens and my 580 EX the flash it did not register. I
know the flash was going off, and I tried various tests to make sure
the flash wasn't malfunctioning. I had to open up the lens to f3.5 at
1/80th and 1600 ISO before the light would register, and I wasn't more
than eight feet from the subjects. Even then the images were often too
dark. Conversely, when I took the 24-70 off the camera (5D) and used
my 70-200 2.8L I got perfect response every time. I finally stopped
using the 24-70, since there was no way to rely on it. Anyone else
have this problem?

There's talk online about Canon making some "bad copies" of this lens.
Problem? No one knows when/if they were made, what U-numbers they are,
nada until you get one, apparently. Paying well over $1000 for a "bad
copy" of anything is not gonna make me happy. Has anyone worked with a
24-70L they consider a "bad copy," and if so, what's the date code on
them?

All I want is a lens I can count on. Thanks.

JJ