# Canon shutter message upon powering off (update) Does NOT appear with native lenses



## mangobutter (Mar 6, 2019)

I just received my RF 35 IS today. Guess what. No warning message. The flap closes immediately and there's no message.

Turns out this message is ONLY when you have the EF to RF adapter attached. 

Since there does not appear to be anything different mechanically when the adapter is being used vs. not used, I am puzzled as to why the camera works perfectly as every other camera when native lenses are used. 

TURNS OFF INSTANTLY AND SHUTTER PROTECTION FLAP CLOSES INSTANTLY UPON POWER OFF. JUST LIKE ALL THE OTHER CAMERAS. =)

YUP.


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## Kit. (Mar 6, 2019)

Maybe it wants shutdown confirmation from a lens, which is not supported by the older lenses, and then it just waits for a timeout.


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## neuroanatomist (Mar 6, 2019)

Explains why I haven’t seen the message, I’ve only used the RF 24-105/4L IS so far.


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## Reeperbahn (Mar 7, 2019)

mangobutter said:


> Since there does not appear to be anything different mechanically when the adapter is being used vs. not used, I am puzzled as to why the camera works perfectly as every other camera when native lenses are used.



Untrue. 

RF lenses have their apertures fully closed when no power/camera is attached. 

EF lenses have the aperture fully open when no power/camera is attached.


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## Kit Lens Jockey (Mar 7, 2019)

This is how other mirrorless cameras handle the aperture too. I wonder why it's seemingly not possible to close down the aperture when using EF lenses with the adapter. When using EF lenses on a Sony using a mount adapter, they would close down there apertures when the camera was shut off.

I believe the message is not necessary when the aperture closes down because there is less chance of the sun coming through the lens and burning the shutter when the aperture is closed down.


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## Reeperbahn (Mar 7, 2019)

Kit Lens Jockey said:


> When using EF lenses on a Sony using a mount adapter, they would close down there apertures when the camera was shut off.
> 
> I believe the message is not necessary when the aperture closes down because there is less chance of the sun coming through the lens and burning the shutter when the aperture is closed down.



^^ do they? And the lenses keep the apertures closed when you disconnect them from the camera? Interesting. I thought it was something like a spring or mechanical thing. Anyway, it could be something "historical" in the EF protocol that remains unchanged to stay compatible with all products in the portfolio. 

The Viewfinder in a SLR always shows the open-aperture to have a bright viewfinder image. So it does make sense that EF lenses have open apertures as default when no electricity or mechanical force is applied. The RF lenses seem to have closed apertures as a default to protect the camera from sunlight (which is less necessary on a SLR because of the mirror?) or for whatever other reason, that we all do not know anything about. 

Maybe EOS Cameras just have no sensor for the current status of the aperture, but always assume that every connected lens is connected with open aperture, and start calculations and control the aperture motors on that basis. And for that reason, the EOS-R also has to open the apertures of connected EF lenses when disconnecting them, to make them work on EOS SLR without trouble? Just speculative. But there surely is a reason. 

One may think that Canon is stupid and *******.
Or one may ask for the reason and understand.


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## Kit Lens Jockey (Mar 7, 2019)

Yes, EF lenses used on Sony bodies close down their apertures when you shut off the camera, and they stay closed when you take them off the camera. It kind of bugged me a little bit because it made my lenses seem broken, but ultimately it's not that big of a deal and I just got used to it back when I was using Sony.

Also, if you remove a lens from a Canon DSLR while the aperture is closed down (like if you use the DOF preview button), the lens stays closed down after it's removed from the camera. So, EF lenses have no spring or anything like that that holds the aperture open. It just is where ever the camera leaves it.

Also, if you put a lens with a closed down aperture onto a Canon DSLR, it immediately opens the aperture back up, I think even if the camera is off. So, I can say pretty definitively that Canon DSLRs can definitely tell when the aperture is open or closed. Either that, or they just mindlessly send a pulse to open up the aperture whenever a lens it put on the camera, just to make sure it's open.

So ultimately, it's just weird to me that RF lenses get their apertures closed down when the camera is shut off, but EF lenses don't. They're definitely physically capable of it, and they do when you use them on Sonys.


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## Reeperbahn (Mar 7, 2019)

Kit Lens Jockey said:


> So ultimately, it's just weird to me that RF lenses get their apertures closed down when the camera is shut off, but EF lenses don't. They're definitely physically capable of it, and they do when you use them on Sonys.



thanks. interesting to know. 
Would be great if one could just ask one of the engineers behind the lens protocols.


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## Kit Lens Jockey (Mar 7, 2019)

I wonder if perhaps Canon's _official_ specs for EF lenses dictate that the aperture should stay open when the camera is powered down. But, since the Sony adapters are obviously not official Canon devices, they may bend the rules a bit and close the aperture anyway. It might be a case of the lens being physically capable of doing it, but Canon's own rules and specifications for EF lenses don't allow for it.


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## neuroanatomist (Mar 7, 2019)

Kit Lens Jockey said:


> I wonder if perhaps Canon's _official_ specs for EF lenses dictate that the aperture should stay open when the camera is powered down. But, since the Sony adapters are obviously not official Canon devices, they may bend the rules a bit and close the aperture anyway. It might be a case of the lens being physically capable of doing it, but Canon's own rules and specifications for EF lenses don't allow for it.


Makes sense. At least on Canon DSLRs, the only way to get a lens to keep the aperture closed is to set a narrow aperture, then press the DoF preview button and simultaneously detach the lens.


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