EOS R10 locks up with Rokinon 14mm f/2.8ED AS IF Lens

[hdecinin]

I have a Rokinon 14mm f/2.8 lens with the EF mount and AE control which I normally use on my EOS 6D MkII with no issues.

When I bought the R10 2 years ago I also bought a Viltrox EF-R2 adapter. 

This combo works flawlessly with all my EF lenses on the R10 except the Rokinon.

With that lens the camera locks up as soon as I press the shutter button. Only way to free it is to pull the battery & that's not a good thing to do.

Tried it on a friend's R5 with the same results both with my adapter & his Canon one.

Here's where it gets interesting.

Earlier this week I was at Gene's Camera in South Bend. While my buddy was shopping, I was telling a sales rep about the issue.

At his suggestion I got the lens & and adapter from the car. We put it on a used R6 he had in stock and it worked perfectly. Also tried it with a used Promaster adapter with the same results.

Is there perhaps an R10 menu setting that could be changed so that this lens/adapter combo could be used on the R10? Have been looking through David Busch's R10 book and the manual with no luck.

Any help is appreciated.

[kvbarkley]

Of course we recommend the Canon adapter, but that does not seem to be your issue.

Have you tried the "lens drive when AF is impossible" setting for AF?

[hdecinin]

Tried it but result is the same. Instant lock up when I press the shutter.

I should say that I bought the lens for night sky work with the 6D MkII. It does that just fine & I prefer the full frame in low light.

I'm just curious why it doesn't work on my R10 but does on an R6.

Thanks for taking a shot.

[Waddizzle]

You need to contact Rokinon about a lens firmware update.  Your issue isn’t new. 

[shadowsports]

Greetings,

I think this is ultimately going to come down to a possible firmware update (as suggested by my colleague).  I understand this lens has an AE chip, and even if you use a Canon Adapter, It doesn't mean it's going to work with every mirrorless body out there. I have the 12mm f2.8 (no chip).

Since you are having a communication issue, the last thing you can try is enabling "release shutter without lens attached" on the Custom Functions menu Tab 4.  

If that fails your only hope is going to be with Rokinon / Samyang. 

Good luck.  😉