Spectacular lens

Velocity of Sound wrote:

glassoholic wrote:

My feeling is that it has the quickest AF drive of any lens I have tried... really turbo charged!

I just recently bought one, and have only had the chance to use it on still objects around my apartment. My sense is that the autofocus speed is about the same as the other "pro" lenses (12-100mm, 25mm f/1.2, and 17mm f/1.2 are my comparisons; the 8mm f/1.8 is pretty quick but it generally doesn't need to do much focus adjustment so I don't have a good feel for its speed). I know from the initial press release that the autofocus motor design is a bit different than the other lenses from that time period; I'm not sure if that became Olympus' standard design moving forward.

I like the 40-150mm so far, too. Haven't had a chance to test image quality, but if it's anything like the 12-100mm (and based on reviews, it should be) then I'll be very pleased. Size and weight aren't issues to me, but I'm used to 4/3 lenses.

The only odd things I've noticed:

1) When you adjust the zoom, in a dead-silent room or if you put your ear to the barrel, you can hear something mechanical whirring as you adjust. You can see the lens adjusting even when removed from the camera so I know the zoom mechanism isn't a powered feature, but I found that interesting.

2) This is the only m.Zuiko lens I have that closes the aperture down when you turn the camera off. I don't know the reason for that.

The sound you hear is the AF refocusing as the lens is not parfocal but is trying to be parfocal by AF adjusting as you zoom.