I recently reacquired the Fuji 56f1.2. It's a fantastic lens and I should never have sold it.
However, my new copy of the 56 occasionally makes a humming sound that persists after acquiring focus in AF-S mode. I don't recall my old 56 ever doing this on my X-T2 so now I'm slightly concerned.
For the rest there doesn't appear to be anything wrong with it.
At about one in a 20 shots, especially at minimum range (though I've also had it happen at infinity), the auto-focus motor keeps humming after acquiring focus. Sometimes it stops after a few seconds, but I've also had occasions where it wouldn't stop until I'd press the focus button again or switch off the camera. It happens in AF-S mode.
My question is: do other people with the 56 experience this occasional after-focus hum as well, or could it be that I got a bad copy? And my second question is; could it possibly damage or shorten the lifespan of the lens when the autofocus motor keeps running after acquiring focus? I would hate to have the lens work for two years and then break just after the warranty has expired. And my last question: would you keep it and try your luck, or would you return it to the shop and exchange it for another copy?
Edit: Problem solved, see my post below.
Edited by Mervyn, 04 August 2017 - 07:52 PM.