Occasional faint metallic sound with EF 100-400mm mk II while focusing

Mika Y. wrote:

Hi,

I noticed a few days ago that my 100-400mm mk II occasionally but not always makes a faint kind of metallic sound when focusing from the infinity towards a closer target. Anyone had a similar change in behaviour?

I've owned the lens for about 6 years and I'm quite sure this hasn't happened until now. Focusing seems to work just fine though, and there's no any kind of noticeable slowdown or pause in focusing even if I hear this.

Other observations:

- If I use manual focus, there's no any kind of extra sound or change in how the focusing ring turns

- This doesn't ever seem to happen if I focus from the minimum focus distance or close to it towards infinity, so this seems to be kind of one-way issue

- Focal length does not seem to matter

- Whether IS is on or off doesn't seem to matter

Thus, I suspect this has something to do with the AF motor or mechanisms transferring the torque to the lens group(s).

Obviously any unexpected sounds with a piece of camera equipment are worrisome and I guess I should get the lens checked by a local authorised Canon repair shop in near future in case this is something that may result to loss of functionality over time. But checking just in case someone has experience about similar issue.

sounds like you are not familiar with canon telephoto lenses. there are many many moving parts inside the barrel so the noise is expected.  there is nothing wrong with your lens. this noise doesn't effect the focus accuracy or anything else. just get use to it and ignore it.

good luck.