300L F/4 IS USM "Clicking" Sound

[cspratt]

I just received my new Canon 300 F/4 IS USM lens and tried it out (handheld) on my backyard bird feeder, trees etc. When in autofocus mode there is a "clicking" sound before and after I press the 10D shutter. My 28-135 IS lens is very quiet in this regard. Is this "clicking" sound normal for this larger lens? Seems to be working fine but I haven't checked the images on my computer yet.

[Ken Fong]

I experience some hum along with some jitter when using my 100-400 with IS...more noticeable toward the 400 end. This is probably the IS mechanism. IS is activated when you hold the trigger halfway down (and if the IS switch is on). From what I have been told, it is normal. If you turn off the IS, it might confirm this. It is also less noticeable on my 28-135 like yours. So far, the jitter has not affected my photos, but I have learned not to leave IS on by default.

[cspratt]

I experience some hum along with some jitter when using my 100-400 with IS...more noticeable toward the 400 end. This is probably the IS mechanism. IS is activated when you hold the trigger halfway down (and if the IS switch is on). From what I have been told, it is normal. If you turn off the IS, it might confirm this. It is also less noticeable on my 28-135 like yours. So far, the jitter has not affected my photos, but I have learned not to leave IS on by default.

Mine is just one loudish "click" before and after I take the image.

[Ken Fong]

If it is just a single click sound, the only thing I can relate that to is the autofocus 'waking up'...but I'm not sure why it would be there after the shot. I would guess it is louder on a larger lense because there is more glass to move...just my guess. I suppose other folks on this forum can confirm this. I'll check this with my lens tonight...

[robertwgross]

If it is a lens sound, for sure, then that is one thing.

Just make sure that it isn't a mirror lockup sound that you were unaware of.

---Bob Gross---

[cspratt]

If it is just a single click sound, the only thing I can relate that to is the autofocus 'waking up'...but I'm not sure why it would be there after the shot. I would guess it is louder on a larger lense because there is more glass to move...just my guess. I suppose other folks on this forum can confirm this. I'll check this with my lens tonight...

Appears it is the IS as there isn't a sound when this is turned off. Holding my ear close to the lens I get a click, a whirring sound, and then another click.

[Ken Fong]

Yeah, this is what I experienced. I panicked at first when I heard AND saw this, but others told me it was normal. Have fun with your new lens.