Hello friends,
As the title indicates, I own an EF 100mm f/2 USM with an issue.
The autofocus motor no longer works as it should.
Instead of fluidly focusing, it "jumps" (usually about twice) for very incremental focus shifts and sounds more like a stepper motor than an ultrasonic.
If you keep pressing the shutter release halfway down, it will eventually get into focus after some time.
Even when it does though, if doesn't confidently lock focus the first time.
It will focus near to far several times before finally locking.
It behaves the same way in AI servo, but it doesn't give up as quickly.
I've tried it on several camera bodies and it behaves the same way (my other lenses work fine on them).
I've owned the lens for several years and it worked perfectly the last time I used it a couple of years ago.
During that time, it was in my climate-controlled bedroom where it wasn't dropped or exposed to water.
The automatic diaphragm and focus helicoids are still fully functional and the optics are clean.
Using it in manual focus, it works fine.
It will capture photos and never presents an error to the camera, but, due to the issues described, it's nearly useless as an autofocus lens.
I interacted with an eBay vendor who had a lens with the same issue, but he didn't know what caused it either.
Does anyone know what the problem is and if it can be resolved?
Is this a manufacturing defect that affects only certain batches of 100mm f/2's or one that will affect all of them at some point?
As the title indicates, I own an EF 100mm f/2 USM with an issue.
The autofocus motor no longer works as it should.
Instead of fluidly focusing, it "jumps" (usually about twice) for very incremental focus shifts and sounds more like a stepper motor than an ultrasonic.
If you keep pressing the shutter release halfway down, it will eventually get into focus after some time.
Even when it does though, if doesn't confidently lock focus the first time.
It will focus near to far several times before finally locking.
It behaves the same way in AI servo, but it doesn't give up as quickly.
I've tried it on several camera bodies and it behaves the same way (my other lenses work fine on them).
I've owned the lens for several years and it worked perfectly the last time I used it a couple of years ago.
During that time, it was in my climate-controlled bedroom where it wasn't dropped or exposed to water.
The automatic diaphragm and focus helicoids are still fully functional and the optics are clean.
Using it in manual focus, it works fine.
It will capture photos and never presents an error to the camera, but, due to the issues described, it's nearly useless as an autofocus lens.
I interacted with an eBay vendor who had a lens with the same issue, but he didn't know what caused it either.
Does anyone know what the problem is and if it can be resolved?
Is this a manufacturing defect that affects only certain batches of 100mm f/2's or one that will affect all of them at some point?
