lightrule對sigma的描述: (18-125OS) The lens has a very strange issue. It seems to engage the OS feature MORE THAN IT SHOULD. You hear a "faint radio white noise" MUCH OF THE TIME, even when you are not using the OS. It will turn off after about 45 seconds of non-use, but once you AF, it goes on again. When I halfpress the shutter, the OS engages (as it should). But when I release the shutter button, instead of the usual 2 second shut-off delay, it just continues for about 45 seconds. Looking through the VF, you can see the OS trying to still stabilize the image, even long after you've released the shutter. It *must* be draining the batteries! See this DPR thread showing others experiencing the same thing (read through all the posts thereafter) http://forums.dpreview.com/forums/read.asp?forum=1029&message=28250678 .