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Possibility of 1/8 aperture increments on EF-lenses in video mode ?


On my canon R7, I find the possibility of 1/8 aperture increments on RF lenses useful when shooting video. How ever when connecting some of my old L EF glass with the basic EF-RF adapter this menu is not available. I know for a fact that EF lenses work internally with 1/8 stops aperture increments. Thus, it must be a software limitation from Canons side.

I am thinking of buying the control Ring Mount Adapter EF-EOS R for my canon R7 andI think I’ve read somewhere that you can get the adapter controlring serviced to do 1/8 stops with EF lenses. Nevertheless, I cannot seem to find the source for this information again. 
Du anyone know if Canon offer this service?


Best regards Lars 🤗



“ How ever when connecting some of my old L EF glass with the basic EF-RF adapter this menu is not available. I know for a fact that EF lenses work internally with 1/8 stops aperture increments. “

I’ve never used a consumer lens or camera by Canon that was able to do that.  They can do 1/3 stops, yes, but not 1/8 stops.

I think you’re overthinking this.  Have you considered cinema lenses?  They can have “de-clicked” aperture control rings.  Canon makes and sells cinema lenses, but they can be costly.

Rokinon makes a line of fully manual, cinema lenses, all of which have “de-clicked” aperture rings.  I would not recommend any of their auto-focus lenses, or any lens by any manufacturer that communicates with the camera body at this time.

"The right mouse button is your friend."

Thank you for your response 👍 you might be right, but I do experience visible exposure fluctuations with 1/3 stops. You are right about cannons cinema lenses being too expensive for me and the two Samyang I owned exhibited various aberrations that I could not accept for my photo work.I did buy som old prime Nikkor glass that I declicked myself. However, I often do photos and video, so it would be more convenient if I also could use my EF lenses.


I have never used a Samyang, but they are joined at the hip with Rokinon.  I want to point out that the fully manual Rokinon cinema lenses are not just de-clicked versions of the their photo lenses.

[EDIT] I think I used a 6D and a Rokinon 14mm T3.1 for this shot.  I love the lens because the hyperfocal distance is only is so short that everything is in sharp focus.


"The right mouse button is your friend."


Good evening ,

If I recall you can have the control ring adapter D-clicked as well, but as Waddizzle states, aperture increments are only 1/3 stops.


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what is the reason the purpose for de-clicking the control ring adapter if still only does 1/3 stops ? Does it remove mechanical noise from clicks ?


1/8-stop aperture increments are only supported when using RF lenses in movie modes.

These are the screen captures from my EOS R6 Mark II fitted with an RF lens - the menu item is shown, and also when fitted with an EF lens on the control ring mount adapter and no menu item is shown.

This is also written in the manuals that EF and EF-S lenses are not supported for the 1/8 aperture increments capability. I added the 1/8-stop aperture menu item to the My Menu section on my camera. When EF lenses are fitted and I choose the menu it says the function is not available because of the attached lens.

RF lens on cameraRF lens on camera1/8-stop aperture with RF lens1/8-stop aperture with RF lensEF lens on mount adapter menu disappearsEF lens on mount adapter menu disappears

Brian - Canon specialist trainer, author and photographer
I use British not American English, so my spellings may be a little different to yours

Thank you Brian for documenting how it works in the camera menu 🙏

Nevertheless, I wonder if the limitation to EF lenses is done due to attainableness or marketing of RF lenses 
As I previously stated , I know that EF lenses work internally with 1/8 stops aperture increments

RF lenses aren't just EF lenses with a different mount. They're quite a bit more advanced. I'm attaching a brochure that came out with the launch of the EOS R system that does a great job of explaining some of those advancements (at least I think it does). eos-r-system-brochure.pdf

I hope this is helpful! 

EF lenses do not work that way. If they did, then how would it be possible to set the increment to 1/3?

"The right mouse button is your friend."