I've seen this lens listed as something the GH2 can use. Looks tempting, but would it work well?

Fujinon 16x 9 5 162mm F 1 8 B4 Lens for Panasonic GH2 GH1 with Micro 4 3 Adapter | eBay (http://www.ebay.com/itm/Fujinon-16x-9-5-162mm-f-1-8-B4-Lens-for-Panasonic-GH2-GH1-with-Micro-4-3-Adapter-/181059916900?pt=Camera_Lenses&hash=item2a28031464)

You'll need rails for it, unless I'm mistaken, but the lens looks extremely large and heavy. Kevin M or another lens guru around here will be able to chime in and give a better answer.

You ask if the lens would work well. You didn't say what you'd be using it for. On paper, the lens sounds amazing. But how practical is it?

If you put it on a rig with rails it would be much more usable in more situations.

I hope you buy it and then report back to us, sounds very interesting.

It's only useful in ex tele mode - you can get other similar lenses that have their own 2x extender that will work on the GH2 without the ex tele (it won't be 1.8 though)

I've thought about something like this but I'd really like to be able to test it thoroughly before parting with cash

The one thing that is frequently overlooked about using old SD video lenses on HD cameras is that the glass is not made to HD standards. This means that you can have blooming on highlights, chromatic aberrations in zoomed shots and overall reduced detail when compared to 35mm lenses or lenses specifically designed for DSLRs. These problems were never visible in SD so the lens makers didn't have to make the glass to higher standards. While some SD lenses apparently do not have any visual defects when adapted (see the footage with a different SD video lens posted earlier this month), reduced detail seems to be unavoidable. Now this may not be terrible for every shot, it should be kept in mind for overall usability.

This eBay listing is interesting but without actual footage, outdoors on a sunny day and indoors in a dark setting, zooming in and out on detailed subjects, I would be very careful purchasing something like this.