to use it on the gh2 you need to use something like the red rock micro live lens, which is much more expensive than a nikon g to m43 adapter. with that said, I have heard it is annoying to use a nikon g lens on an ef mount. So I would say that the major disadvantage would be the cost and bulk (they need to be powered also) of an adapter. One thing you could do once you get the BMC is to buy a "dumb" ef to m43 adapter, set the aperture on the bmc and then remove it and put it on the gh2. there is no great way to do it without the duclos mod.

you need to make sure it is a nikon g to m43 adapter, it will have an aperture slider. Canon ef lens apertures can only be adjusted electronically (other than rokinon manual ones etc.)

there is a canon ef to m43 adapter with blades in it. You might be interested in that for your GH2?

DirkVoorhoeve and Alex. Thanks for your replies on the subject.

I have found the Fotodiox Lens Mount Adapter, Nikon G-type lens to MFT Micro 4/3 four thirds cameras, which work with Olympus Pen E-PL1, E-P2, E-P1, E-PL2, Panasonic Lumix DMC-G1, G2, GH2, GF1, GH1 G10 http://www.amazon.com/Fotodiox-Adapter-cameras-Olympus-Panasonic/dp/B003Y2XN9G/ref=sr_1_5?ie=UTF8&qid=1337676584&sr=8-5

My concern is to get one that allows me to change the aperture manually. The only one I have found at the moment of this writing is the Novoflex at the link below; but it is really pricey, around US300. I'm looking for one with similar feature but cheapest.

Novoflex Adapter MFT/NIK for all Nikon Lenses to MicroFour Thirds Camera Bodies - Manual Aperture Control Ring for Nikkor G-Series Lenses

http://www.amazon.com/Novoflex-Adapter-MFT-NIK-MicroFour/dp/B002MXFGJI/ref=sr_1_1?s=electronics&ie=UTF8&qid=1337657529&sr=1-1

Beside the KIPON, is there another alternative to the Novoflex? If there is not, I might have to go with the Novoflex.

Thanks to all for the responses on this subject. Today I got the Tokina 11 - 16mm f2.8 with the Nikon mount. I found an adapter that allows manual aperture control for the lens: "Pro Optic Nikon "G" lens to Micro 4/3 Body mount for Olympus PEN E-P1, PEN E-P2, Panasonic Luxix DCM-GF1, GH1 and GH2." It works as expected. Price, US59.95. I tried it at the store first. There is no vignette at any focal lens. And the aperture control is by steps, so we know every time the aperture we are dialing.

Adapter link: http://www.adorama.com/CZNKG43.html There are cheapest ones but without the manual aperture control.

Once again, the purpose to buy the Nikon mount version is to be able to use it later in the BMC with the Canon EF adapter. Buying the other way around, Canon mount first, I wouldn't be able to control the aperture in the lens.

Thanks for asking.

Maybe I'm missing something.

This adapter is made to very precise and high standards to ensure exact infinity focus on the Canon camera. With the EOS/NIK-NT adapter automatic exposure metering via stop-down metering is possible as is aperture priority auto exposure. The new adapter features a lever on the side of the adapter to let users control the aperture on G series lenses.
http://www.amazon.com/EOS-NIK-NT-Adapter-Lenses-Cameras/dp/B003NF1S28/ref=pd_sim_sbs_p_3

I hope I got it right. In the meantime, I'm going to enjoy the Tokina with the GH2.

I'm glad we are in the same page now! Thanks for the eBay link. I have until the BMC gets out in July to research other Canon adapter options.

@willianaleman Yep you have it right. I went through the same situation trying to find an adapter that worked. Non of the cheap china ones worked for me at all. The only one that worked was the Novaflex which costs a buttload. I never did try the one you bought though. Have you checked your infinity focus really good? For some reason with that lens, it's pretty hard to get it right with cheaper adapters. You prob need to go a little past infinity to get it right.

vicharris , thanks for your commend. Because even in manual mode the internal focus (IF) motor is still working in this lens, it makes uneasy to find the exact focus. The adapter works perfectly.

"it doesn't have constant aperture..." what do you mean?

Psyco, thanks for asking. It means that the lens aperture changes as you zoom in/out, which  becomes a nightmare in post during color grading.

"The Tokina 11-16 has a constant aperture of F2.8 from 11mm to 16mm."

I need a lens with constant aperture in the whole range. The Tokina  doesn't have it.

"...too much distortion at 11mm..." do you mean the normal  "distortion" you get with such a wide field of view or the barrel  distortion most wide lenses suffer? (I thought the barrel distortion  of this lens is within limits)."

The barrel distortion. I bought this lens because of all the wonderful  reviews it has, but the numbers on these reviews don't match my  expectation in terms of minimum distortion. In addition, none of these reviews  mentioned the variable aperture changes during zoom in/out. Then, we never know for sure until we try.

@willianaleman

Are you saying that in full manual mode, when you zoom in the exposure changes?

kavadni 9:55PM

"Are you saying that in full manual mode, when you zoom in the exposure changes?"

Yes. Exactly

jasonp 9:33PM "Just to clear something out, are you saying that you weren't able to have an f/2.8 at 16mm? Or was the aperture shifting while zooming and then you had to set it back?"

The aperture was shifting during zooming.