There is an update for the 90v. My lens shipped with version 1.4.7 and there is a 1.4.9 out which "optimizes shutter performance in low battery conditions." I haven't noticed any difference but I also don't have a low battery. It does not seem to dampen the shutter sound which is much louder than the other v lenses. I seem to vaguely remember someone saying auto focus was better on fully charged batteries so maybe this address it.