Anyone have any experience with one of these, preferably on GH3 or GH4?

Focal Reducer Speed Booster Adapter Canon EOS EF lens to Micro 4/3 mount GX7 | eBay (http://www.ebay.co.uk/itm/Focal-Reducer-Speed-Booster-Adapter-Canon-EOS-EF-lens-to-Micro-4-3-mount-GX7-/221372726327?pt=UK_Photography_CameraLenses_Lens_caps_hoods_adaptors_ET&hash=item338ad7bc37)

I know it won't give aperture control, nor with it give any IS functions, nor will it give any aperture feedback etc, but in general, does they work well enough (quality wise)?

Metabones don't appear to have their adapter available yet (unless you know different and I'm blind), so what are other people using?

I have lots of EF glass I'd like to use during the transition to the GH4.

Its difficult to find any information about the manufacturer or this product. How would you use it with L-Series lenses without aperture control?

I'd be interested if you learn more about this.

Thanks for the reply.

Not all EF lenses are L, or even Canon.

Some Canon L lenses can be used wide open much of the time, especially if you're adding vari-nd which I was used to doing on the DSLRs

ND was something I really missed coming from real video cameras in the past, and a reason I bought the C100 some time ago, but of course none are 4K and now I have some 4K jobs coming up.

Lenses like the 70-200 f2.8L IS II work well wide open with vari-nd.

Other lenses, such as the Samyang primes (which I have in EF mount) are all manual anyway, including gears for follow focus. So with that in mind, not everything will need to be wide open all the time.

I'm totally open to alternative suggestions, so feel free to post links to any adapters you have, good or bad (say which is which!).

Good points.

The thing I like about the SpeedBooster adapters is the change in crop factor but there very expensive. I really miss camera stores where you can touch things and see if they work before you purchase them..

Continue the conversation here:

http://www.dvinfo.net/forum/panasonic-lumix-gf-gh-series/524541-metabones-ef-m4-3-a.html

You might try this:

Amazon.com : Fotodiox Pro Lens Mount Adapter with Built-in Aperture Iris, Canon EOS EF (NOT EF-S) to Micro Four Thirds (MFT) Camera : Camera & Photo (http://www.amazon.com/Fotodiox-Adapter-Built--Aperture-Thirds/dp/B005ODK53K/ref=sr_1_10?ie=UTF8&qid=1410534286&sr=8-10&keywords=fotodiox+lens+mount+adapter)

I have ordered one. I will post again after trying it.

Kent

Thanks for the replies. Now that metabones have released their active solution, that is the way I will be going.

I tried the Fotodiox lens adapter on my GH4 with a variety of Canon glass. I did not care for the complexity of getting the focus and exposure correct while shooting video. It works ok for stills if you are not in a hurry. I will send it back.

I am using the Metabones Speed Booster since Thursday with the Canon 70-200mm f2.8 II lens and really like it so far. I have also tried it a bit with the 100-400mm and the 500mm F4.