Greetings -- just tried out a Panasonic Leica/Dicomar 100-400 mft lens. PRICEY !! Lens was in auto focus mode - I threw focus out - it took about 4 sec for focus to lock on again -- and when it did - lens focused about 8 to 10 feet BEYOND my main subject - which was centered in lens framing. Branches/bushes moving in the wind where lens focused. Should not be why lens focused where it did.

At 400mm - which should be about 800mm due to 2x crop factor of camera - there was some vignetting all four corners. My biggest concern is the autofocus issue - 8 to 10 feet off ! - beyond subject.

Any other experiences out there like mine ? How did you fix/resolve ? Do you think I can fix vignetting by adjusting VSM in camera ? Feedback and solutions much appreciated ! Have a great day --

I never use auto-focus so I can't help there, but the VSM should be able to take care of the vignetting, dial it down until it's not there anymore.

And I'd just note that the lens is a 2x crop factor, but the sensor on the LS300 is s35 so it's more like a 1.5 crop factor with a lens that will cover it.

If you think that the panasonic is expensive then get a Canon EF 200-400mm F/4.0 L iS USM Extender 1,4x instead for approx the same reach :)

The autofocus for video is not good with any lens you will put on the ls300, if you want better autofocus performance then buy a videocamera with a fixed lens, otherwise always manual focus with lenses that have such a reach.

Also like Jay said, the vignetting is caused by a wrong vsm percentage.