EOS R5 Mark II won't take a photo with a Rokinon 14mm lens

[shawl]

I am trying to use a Rokinon 14mm f/2.8 ED AS IF UMC with AE chip lens on my Canon R5 Mark ii that was purchased new in 2018 for use with a Canon 5diii. (The lens is still available and, from the B&H site, is NOT recommended for the R5ii!) Lens is manual focus without stabilization. Lens is fine with my Canon 5d mark iv. Proper Canon adapter is used. When the shutter is depressed, it seems via sound that an image has been taken; the red recording light goes on but nothing happens...camera is locked up until the battery is removed to reset.

I have tried a number of things: release shutter w/o lens turned ON; when I checked to be sure the focus mode was manual, it was. When I checked to be sure image stabilization was off, it was.

None of this allowed a picture to be taken.

Perhaps nothing can be done, but if anyone has further suggestions, that would be appreciated.

[deebatman316]

This would happen with older 3rd Party EF lenses from the film era. The lens would draw too much power to stop down the aperture. This is likely what’s happening with your lens. Sometimes the camera will report the error or just lock up. So Rokinon will have to update the firmware for it to be compatible. Canon doesn’t know how 3rd Parties make their lenses work on their cameras. Instead it’s reverse engineered to work. 

[zailgan]

How do explain that it works on R5 and doesn’t on R5m2. Lens is not so old :). Camera shouldn’t freeze, it’s professional device, it may show error but not freeze. There is incompatibility between lens and camera R5m2.

[deebatman316]

Easy the same lens can work fine on an older camera but not a new one. Just like my example a family member upgraded from the EOS 10D to the EOS 40D. None of their old Sigma lenses would work on their new camera. Instead the camera would lock up or throw an error code. The lens wasn’t that old either. Canon DOES NOT tell 3rd Parties how their lens mount communication works. Instead it’s reversed engineered to make their lenses work which doesn’t always work. Canon can ensure forward and backward compatibility. A 3rd Party manufacturer cannot. I can use the very first EF lenses on my modern camera and have no issues. But yet a lens from a few years ago is incompatible. Same thing goes with flashes how can I use a 25 year old Canon 380EX. But yet a 3rd Party flash from a couple years ago doesn’t. It’s all reverse engineered so forward and backward compatibility IS NOT ensured. 

[Waddizzle]

“ This Rokinon has manual focus but diaphragm is automatic. So it’s not fully manual lens. “

This thread is about the fully manual lens that is pictured below, then please start a new.  The lens under discussion is fully manual with a focus confirmation chip.  It also has a manual aperture control ring. 

 

[shawl]

I have to respectfully disagree. The lens DOES automatically change f/stop when used in shutter priority mode. (I just test this on my 5d mark iv.)

[shawl]

I'm not seeing any firmware updates on the Rokinon site. 😰

[shawl]

I agree with all you say. Yes, the R5mii does lock-up...I again just tried it! There are no firmware upgrades on the Rokinon site I'm afraid.

[zailgan]

I have two lenses Rokinon, first is fully manual lens 24 f1.4 and recently purchased 35 f1.4 with manual focus. Just checked first one and it works without any issues, but second one doesn’t. Also I found that focus confirmation works differently on them. May be this is problem, will try to play with settings. My plan to use them for Astro photography.

[Waddizzle]

This lens is a fully manual lens.  Just because it may display an aperture setting doesn’t mean that the camera is controlling aperture.

 

Rokunon does make a fully automatic 14mm lens, but this one is not it.  It has an aperture control ring, something that is not normally used on Canon EF mount lenses with automatic aperture control. 

[zailgan]

Your photo is correct and I don’t see aperture control ring.

With AE chip

 No AE chip

 Second one without AE chip has aperture ring. My version even I have 35mm 1.4 looks like first one. Anyway I found a lot of complains in internet. It looks like Rokinon with AE chip lenses don’t work for newer EOS R cameras such as R6m2, R7, R5m2 and so on. But they work for R6, R5. Also there is no way to update firmware on Rokinon lenses and I don’t think Canon will do it to support third party lenses.