EF 50 1.2 lens will only go to 1.4 on R6

[aharimin]

My camera firmware is up to date, I've tried two different 50 1.2 lenses, and I confirmed the lens does go to 1.2 on my old 5D3. I am using the lens with the mount adaptor, and I have several other EF lenses that work just fine with it. I haven't found anyone with this same problem. What else can I try? (I do not want the RF version) https://speedtest.vet/

[shadowsports]

Greetings,

Take a look at the C.Fn2 (Custom Function 2) menu on your camera and make sure the Set Aperture Range allows the lens to operate at f1.2.  I'm not seeing any compatibility issues listed in the lens or R6 manual, but noted the range for Min Aperture is f1.4 

Let us know if this helps.

[jrhoffman75]

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@aharimin wrote:

My camera firmware is up to date, I've tried two different 50 1.2 lenses, and I confirmed the lens does go to 1.2 on my old 5D3. I am using the lens with the mount adaptor, and I have several other EF lenses that work just fine with it. I haven't found anyone with this same problem. What else can I try? (I do not want the RF version)

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Maybe it is related to this note for the adapter:

 

[ebiggs1]

What's that got to do with the aperture opening up?

[jrhoffman75]

If the question is directed at me Ernie, the note says FoV might change.

That could mean the effective FL is seen differently by the camera and thus the wide open aperture is now seen as 1.4 vs 1.2.

Nothing stated that the lens didn't open up, just that the camera was not displaying 1.2.

OP said it worked fine on 5D Mark III and I verified that it reads 1.2 on my 1D MkIII.

[ebiggs1]

"That could mean the effective FL is seen differently by the camera and thus the wide open aperture is now seen as 1.4 vs 1.2."

I'm not seeing that. I doubt that theory has anything to do with it. My ef 50mm f.2L works like it should on all my bodies and every other one I loaned it to. Rick most likely has the answer and resolution to the issue.

[jrhoffman75]

I had the opportunity to have my 50mm f/1.2 installed on a friends R7 w/EF-R adapter.

It also only shows f/1.4. It must be a R series camera/adapter combination issue since it doesn't occur with DSLRs.

The min aperture setting in the section of the manual Rick posted is a user adjusted setting. Out of the box it is f/91. It controls the stopped down aperture, not how wide the lens will open up to.

I set my 1D X to f/1.4 and the wide open aperture still showed f/1.2.