Focus out of whack on Canon 135mm f/2.0 L?
Hi,
When I prefocus my lens to close focus and then press the AF button the
focus is dead on. But when I put the lens to infinity focus and then let the
AF do it's work the lens visibly misfocusses.
I did some tests + tripod that show the problem. Focus was on the "e".
1. Starting from infinity
2. Starting from near focus
This can't be normal, can it?
When I prefocus my lens to close focus and then press the AF button the
focus is dead on. But when I put the lens to infinity focus and then let the
AF do it's work the lens visibly misfocusses.
I did some tests + tripod that show the problem. Focus was on the "e".
1. Starting from infinity
2. Starting from near focus
This can't be normal, can it?
“To consult the rules of composition before making a picture is a little like consulting the law of gravitation before going for a walk.”
― Edward Weston
― Edward Weston
0
Comments
My own copy of the EF 135mm, f2L USM is not terribly accurate to AF at close focus distances. I use Live View mode and magnification for best results at close distances. I consider this normal behavior.
Moderator of the Cameras and Accessories forums
5D II on heavy duty tripod with MLU and 2sec timer.
Center af point only, one shot mode
Manual mode, f/2.0, 1/30s, ISO 100.
No in camera focus adjustment
Same lighting in both frames.
The results are reproducable meaning that the
differenc between first and 2nd focus attempt
are always the same.
I did this the test because many images shot handheld
in other modes also had a slight backfocus where others didn't.
I have played with in camera focus adjustment which allowed me to
get rid of the backfocus at the cost of introducing a front focus
for the other shots.
― Edward Weston
As I said, my copy of the lens (on any body) is not reliable at close focus distances but it's very reliable at distances of ~12 feet or greater, which is where I use it. I regard the benefits to be worth the effort and expense.
Moderator of the Cameras and Accessories forums
― Edward Weston
The auto focus seemed to work at both close and far subjects?
Sam
Mine does not AF properly at close distance on either a 1D MKII, 40D or 5D MKII. Give it a little room and it works splendidly on all.
For anything close I just manual focus. Not a biggee since I don't really want to use that lens for close focus.
Moderator of the Cameras and Accessories forums
Same problem on another camera body but focus is perfect for anything
further away than about 8m. Guess I'm gonna keep this lens with prices
going up and everything. I begining to really like it as a lens for streetshooting
too. Thanks for taking time to check your lenses and giving advice. Much
appreciated!
― Edward Weston