Hi,

Using a 24-105L on an new 5DIII. Lens snaps right into focus, but there is a motor "whirring" sound right after focus and then a mechanical soft click. maybe less than 1/2 a second after focus. Focus never changes. It's definitely the is the IS motor as there is no noise when I turn it off. Not sure how IS works so perhaps this is normal. Can any owners tell me is this is normal or the experience the same thing?

thanks

I have the 24-105 and the 100-400,, both with IS. I hear the noise with the 100-400, but not the 24-105.

Perfectly normal. What you describe sounds exactly like mine - I just tried it. Of course, there is very little ambient noise here. In many normal situations, you won't hear it, at all.

The IS on this lens is actually more quiet than many older, first-gen IS lenses, like the 300/4L IS. The delayed soft mechanical click is the IS turning off, after you release the shutter button.

Almost all of the IS lenses I've owned have sounded slightly different.

Some people hear the IS motor better than others, and some motors make more noise. Its hard to tell which is which when comparing with another person. If you can, try another lens and see if its the same. They all make noise, but yours might be going out.

Sounds normal to me.

EBH

The 70-200 f/4L IS has a pretty loud (relatively speaking) IS sound. You an easily hear it whirring up and then clicking when it stops. The 300 f/4L is similar with regards to sound.

Thanks guys. I live with 5 women so it's never quite in the house. I've owned this lens for 2 years and never heard the sound, but this morning they were all asleep. . Pictures look great from it so it's all good

SwampYankee wrote:
...I live with 5 women so it's never quite in the house...

you're lucky you don't end up sitting in a corner talking to yourself, so hearing a little motor whirr is all good

erikburd wrote:
The 70-200 f/4L IS has a pretty loud (relatively speaking) IS sound. You an easily hear it whirring up and then clicking when it stops. The 300 f/4L is similar with regards to sound.

+1