Vivitar lens won't work on an EOS R with adapter

[eapples]

Vivitar 8mm 1:3.5 Lens On a Canon EOS R With a Lens Adapter

Hello:  I apologize if I've already posted about this.  I have a Canon EOS R camera.  I use a Canon adapter so that I can continue using the lenses I had on my Canon EOS Rebel.  One of those lenses is a Vivitar 8mm fisheye lens.  It works perfectly on the Rebel, but will not function at all on the EOS R.  When I tried using the lens on the mirrorless camera, nothing worked -- the shutter button would not work; I could not get an aperture reading, nor could I get a reading on any setting on the camera.  I am a technology dinosaur, so my eyes glazed over when I tried to research the issue since I encountered a lot of technojargon.  I am reaching out to the Canon community for some guidance.  Thank you in advance for your help.

[Waddizzle · Accepted solution]

If it is fully manual lens and the aperture displays as F00, then you need find the following menu setting.

Release Shutter Without Lens

The factory default setting is Disabled. 

[Waddizzle]

I recommend only using Av or M modes with fully manual lenses. Avoid shooting modes that require the camera to control the aperture.

[eapples]

Yes, it is fully manual, and the reading is F00.  I will try your recommendation, and I will report back to you.  Thank you.

[eapples]

Others have recommended the same.  I will report back to you when I've had a chance to play with the camera and lens.  Thank you.

[Waddizzle]

“ 

Others have recommended the same.  I will report back to you when I've had a chance to play with the camera and lens.  Thank you.“

Oh, yeah! When using Av mode, you should be able to set an Av value.  Make it match the lens setting. 

[Waddizzle]

Others have recommended the same.  I will report back to you when I've had a chance to play with the camera and lens.  Thank you.“

Oh, yeah! When using Av mode, you should be able to set an Av value.  Make it match the lens setting. 

[eapples]

Hello (again):  Yes, your recommendation worked perfectly.  However, there's a vignette that appears, and it's weird -- a rectangular surrounded by a round.  I can live with that.  At least, now I have the lens working on the mirrorless camera.  Thank you.

[Waddizzle]

“ However, there's a vignette that appears, and it's weird -- a rectangular surrounded by a round. “

What is the exact model number of the lens. It may not have been designed full frame, 35mm film.

[eapples]

The lens has the EFS designation, so I know it's not made for a full frame camera -- I was using it on my Canon EOS Rebel.

[ebiggs1]

The R camera does not know it is a crop lens since it doesn't know anything about the lens.