Using a MFT mounted lens on a full frame camera

Question

A long time ago, I bought 4 Rokinon Cine DS lenses with the MFT mount for my Panasonic GH5. Link to one of them is below.

https://www.amazon.com/gp/product/B00MZCCDA6/

However, since then, I have been interested in getting a full frame camera. Would I need to purchase an all new set of lenses for that? The lenses I bought are listed as full frame, but I am concerned that because I bought the MFT mount there won't be any way I can use these.

I have looked at a couple of retailers and thing like MFT-to-L Mount or MFT-to-Canon RF adapters don't seem to exist.

Any help would be appreciated.

Answer 1

Would I need to purchase an all new set of lenses for that?

Yes.

The lenses I bought are listed as full frame, but I am concerned that because I bought the MFT mount there won't be any way I can use these.

That's a legitimate fear. Samyang/Rokinon does not make interchangeable mounts (except on the Xeen cinema lenses), and the smaller throat of the MFT mount (44mm) will cause vignetting on, for example, the EOS R or Canon EF mounts, which have 54mm throats, if you can even find an adapter, which is highly unlikely because of the similar mount depths.

The flange distance (distance from the lens mount to the sensor where the lens has to be held to achieve full focus range to infinity) with MFT is 19.25mm. EOS R's is 20mm and Sony E's is 18mm. So no adapter will make it compatible with EOS R full focus range (you have to shave 0.75mm off the back of the MFT mount), and 1.25mm isn't thick enough to make an adapter ring for Sony E.

You have to exchange the MFT mount lens for one in the new mount you're moving to, despite the main formulation of the lens being full-frame capable.

It would have been better to say, purchase lenses in Canon EF mount and adapt for MFT use if you were planning on moving to full frame mirrorless in the future. But that's not much use to you at this point.

Answer 2

If you really want, you can adapt your lenses to Sony E-mount and Nikon Z-series bodies. The problems that must be overcome when adapting lenses are:

• Sensor coverage (size of the image circle). Since the optics of your lenses were originally designed to cover full frame, they should continue to do so despite being fitted with a mount that is associated with crop sensors.
• Lens settings (aperture, focus). This is typically a problem with electronically controlled lenses. Since most Rokinon lenses are controlled manually, this probably doesn't apply to your lenses.
• Flange focal distance. The camera you adapt your lenses to must have a shorter FFD than the lens to make room for the adapter. The FFD of MFT is 19.25mm. Sony E mount (18mm) and Nikon Z mount (16mm) are full-frame mounts with shorter FFD.
• Commercial availability of adapters (or ability and willingness to make your own). Adapters to fit MFT lenses to Sony E mount (NEX) and Nikon Z mount are commercially available. It may be helpful to search for the phrase "adapter ring".