I just received my Oly 75mm f1.8. It is one FINE lens. However, I noticed there is a "robotic noise" when it is hunting for autofocus. In dim lighting, it always needs to hunt a little before locking focus and it makes this exact sound in the youtube video. [ame=https://www.youtube.com/watch?v=_2UzlyK2QEg]75mm focusing - YouTube[/ame] Regardless of lighting, it makes that sound--even in broad daylight. It is just noticeably worse in dim lighting because it is hunting. I tried to perform a search on this issue, and it seems that some copies exhibit this and some are "completely silent". But in all the threads I looked up, there was no consensus on if this was normal. It doesn't seem like a well documented issue because my google searches did not get many hits. I know its not defective per se--the lens is sharp as a tack. Just a little annoying, and I would want to exchange it for another copy if this lens was meant to be as silent as the Oly 12mm or 45mm.