I have recently purchased the 18-135 stm lens. I use it on a Canon 60D. I have noticed that it takes a while to achieve autofocus, especially at longer focal lengths. In a couple of cases the shutter has fired before autofocus is achieved and I end up with a totally blurred image.
I have not tried the lens on a different body.
I'd like your thoughts about whether this problem is strictly a lens problem or could it be related to communication between the lens and the camera. I do like the lens for its clarity (when af is achieved) and large range.
Make sure you've got the latest firmware for the 60D; otherwise, remember that the 'STM' lenses are designed to be slower than USM lenses in order to smooth out autofocus performance for video on bodies that have phase-detection sensors on the image sensor (T4i/T5i/EOS M/Rebel SL1).
scalesusa wrote:
I'd upgrade to a 70D if/when it comes out. It will likely be optimized for STM lenses and AF will be faster.
Canon's going to be Nikon's best salesman if they can't get some better low light performance and on-sensor phase-detect performance in the 70D and 7D II. They need that just to bring them up to par.
Thanks everyone. I think I'll go into the "wait and see" mode now and just keep using it. May go down to a local store and check it on some of the newer bodies to see if it reacts the same. If there is an obvious problem, it is under Canon warranty and I can get it fixed.
@BauerPower, have you had any improvements with your 18-135mm STM? I'm also looking at this for my 60d and wondering if this would be an issue. Thanks.
Eventually I sent the lens of to Canon in Irvine. Irvine said there was evidence of impact and that they had adjusted the motherboard. It came back yesterday and still exhibited the same problem. I call them and arranged for the lens to go back to them for another go around. The lens shows the same problems with my wife's XSi. At this point I would say that the problem is with this specific copy of the lens and is not related to the 60D. I will make another post when the much-journeyed lens returns once again.
