Panasonic Lumix GF2 + 100-300mm lens - overexposure problem

[Vincent Lowe]

I've recently bought a Panasonic LUMIX G VARIO 100-300mm / F4.0-5.6 lens for use with a DMC-GF2 camera.  Bought it used, off ebay, but it looks in mint condition.  The camera is fine with the other two lenses but the 100-300 overexposes by about two stops.  It's the same on two other bodies.  I managed to borrow another lens and my camera is fine with that, so it's definitely the lens that is at fault. All tests were done with the same settings in every case, in aperture priority mode, which is what I normally use.

However, if I select the iA (Intelligent Auto) mode it works fine.

Googling doesn't bring up anything so before I send it off somewhere, any suggestions from the experts here would be welcome.
 

[vpics]

Have you cleaned the contacts on the lens. Might be that the lens hasn't been used a lot and a small film has built up which prevents of the contacts connecting properly?

[M.Chapman]

Sounds like the lens might not be stopping down to the desired aperture when the shutter is pressed.

 

Set a tiny aperture and try the depth of field preview mode and have a look to see if the lens is stopping down. You can tell by seeing if the depth of field increases or possibly by looking into the lens.

 

If the lens isn't stopping down, could be the contacts as mentioned above, or a sticky or defective diaphragm.

 

Mark

[Vincent Lowe]

Thanks for the suggestions - I'll do some more tests (I've cleaned the contacts).  There is a comment on another forum about a firmware update for the lens, which I'll investigate.