I have a lot of Canon L-series lenses, is their an adapter that enables me to use these lenses on the GH4?

So I'm guessing from the lack of response that an L-Series lens adapter for GH4 is not available yet?

As far as I understand, any EF to m43 adapter should work on the GH4 just like any other m43 system. Fotodiox has a variety of adapters, but this may be the one you're looking for:

Fotodiox Pro Lens Mount Adapter with Built-in De-Clicked Aperture Iris, Canon EOS EF Lens (NOT EF-S Lens) to Micro 4/3 Four Third System (MFT) Camera Adapter, Fits Olympus PEN E-P1, PEN E-P2, PEN E-PL1, PL2, Panasonic Lumix DMC-GF1, GF2, GF3, GH1, GH (http://www.fotodioxpro.com/lens-mount-adapters/mirrorless-dslr/micro-4-3-mft-lens-adapters/pro-lens-mount-adapter-builtin-aperture-iris-canon-eos-ef-lens-to-micro43-system-camera.html)

I don't have any direct experience with the GH4 so I was hoping someone else would know better.

the L series isn't a specific mount are you talking about FD or EF mounts? whatever it is there is an adaptor to suit - the same adaptors the fit the GH2 or GH3, they are all Micro four thirds mounts

Yes, there are EF and FD mount adapters available for your lenses. Google Canon EF to Micro Four Thirds adapter and you'll find them. I had a couple myself.

Unless something new has come out the adapters are all manual. A company I followed for awhile had promised something that promised full functionality but has not yet come through yet.

Thanks everyone for the replies. I've only used Canon so I didn't know that the the Micro 4/3 mount was the same on all camera's. I'll do some more research.

I'd like to shoot video with the GH4 so IS would be a huge help, I can live with manual focus and aperture but on the longer lenses I'd really like to have image stabilization.

I don't think with the GH4 you will get image stabilization with any other mount but Panasonic's own m4/3 lenses.

I have the GH4 and I just received the FotoDiox Pro lens adapter that Chris Hsiung mentioned. Its pretty dark out here but I did some quick tests on it to see how I liked it.

EF Lenses: Sigma 28-300mm, Canon 50mm 1.8, Canon 17-40L.
Lumix Lenses:12-35mm

Things to note:
- No click stops on aperture ring
- Easily and smoothly connects to camera
- Easily and smoothly connects to lens
- No autofocus
- No IS (if your lens has it)
- You must enable 'Allow camera to shoot without lens' in camera menu
- Cannot connect EF-S lens to adapter
- My thick fingers have some difficulty fitting between manual aperture ring and lens release
- 9/9 aperture = wide open
- 1/9 aperture = closed down
- All vignette tests done by quickly looking through lens, no pictures taken

Canon 50mm 1.8
- Sits about same distance off body as Lumix 12-35mm
- Entire aperture range works without vignetting
- Some play is noticeable between adapter and body when adjusting aperture
- No play noticeable between adapter and body when adjusting focus

Canon 17-40L
- aperture 5/9 to 9/9 no (or barely noticeable) vignette
- 1/9 through 4/9 has noticeable vignette
- vignette changes very slightly across focal range

Sigma 28-300
- aperture 2/9 to 9/9 no (or barely noticeable) vignette at 35mm
- aperture 3/9 to 9/9 no (or barely noticeable) vignette at 50mm
- aperture 4/9 to 9/9 no (or barely noticeable) vignette at ~150mm (no lens marking)
- aperture 5/9 to 9/9 no (or barely noticeable) vignette at 300mm

Play between adapter and body
- The play that can be noticed here is only in the direction that you rotate the adapter on / off.
- I have not checked to see if there is anything that can be done about this.
- I have not contacted Fotodiox or seller yet about this issue.
- I currently do not consider this to be a major issue, but it would be nice to fix.

My primary use of the camera is for stills and video, the majority of the time when I use the camera it is in a scenario where I cannot take extra gear and because of that the Lumix 12-35mm is my primary lens.

If you are thinking of using the Canon 17-40L or Sigma 28-300 you will need to consider whether you need the aperture ranges that are missing.

I would imagine that most of the vignette issues would disappear with an adapter that could translate the electrical signals to allow you to utilize the aperture built into the lens, but I do not know as I do not own one, cannot test one or have enough knowledge about optics to make an educated guess or assumption.

I'll still use the 50mm 1.8 and Sigma 28-300, but I will be using the 28-300 solely as a longer lens for stills.

I will not use this on my 17-40 (never intended to) because it is heavy, vignettes too much and is a similar focal range to the lumix lens that I have.

For macro both the 50mm 1.8 and 17-40L did seem to work well with extension tubes. However, because the 17-40L cannot close its aperture enough I will likely only use it when I really need that extra magnification.

Whether I would recommend the adapter to someone would be based on whether they would need the aperture range that is missing. I feel that the vignette issue would be a problem for any EF to M43 adapter that has a built-in manual aperture ring.

The build quality is acceptable for a $64 (shipped) adapter with aperture ring.

Ranking:
Value: 8/10
Build Quality: 7 / 10 [8.5 /10 if play can be adjusted out]
Ergonomics: 7/10 [9 / 10 if aperture ring easier to adjust]

many dummy adapters for EF lenses to be mounted on M4/3 cameras, but no really smart one:)
redrock LiveLens MFT Active Lens Mount (http://store.redrockmicro.com/livelensmft) allows you to mount EF lens and change the aperture, but i don't know any adapter that alows you to have IS working,
but i really want one!

With the popularity of the GH3 and L-series glass you'd think someone would have developed an active adapter that supports all of the functionality of the lens.

Not having this ability probably wont prevent me from purchasing the GH4 but having to get new lenses is certainly delaying my purchase.

I know that Metabones has a Canon EOS to M43 adapter coming but I don't believe that it will support IS. Whoever does create an adapter that does this will sell a lot of them but would you pay $1,000.00 for it? I bet the technology needed to support the IS would be expensive to develop or there might even be patent issues/licensing that would have to be paid to Canon to support this function?

Metabones is saying August for their adapter. "Dumb" adapters with the built in aperature vingette... put the adapter on and turn on the waveform and you will see the edges go down before the center of the image.

Historical note: AF100 conversation from four years ago... much like pocket cinema camera discussions last year.

Long live the micro four thirds consortium!

here is another one,

Aputure DEC Canon EF Lens Adapter Adjust Iris + Wireless Follow Focus - YouTube

but still in production, and nothing on thier website

got reply from Metabones yesterday, it's coming soon :)

Anyone think the upcoming Metabones Canon adapter will cost the same as their Nikon G to M43 adapter, about $429.00?

Anyone think the upcoming Metabones Canon adapter will cost the same as their Nikon G to M43 adapter, about $429.00?
i wish, but i am afraid it'll be closer to EF to BMPCC one's price :(