Lens Communication Error: Canon R5c + EF 24-70 2.8 II

[andytheslash]

I use a Canon EF 24-70 f/2.8L II lens with my Canon R5c via the OEM lens adapter. I have consistently experienced multiple error messages including "this lens is not compatible" when in slow motion mode, and occasional loss of aperture and focus control when filming video or taking pictures in either mode. The contacts are very clean and are not an issue. I do not have another EF camera to test this lens on.

I am able to use other EF lenses with no issue with this adapter.

[John_Q]

Hello andytheslash,

There are certain scenarios where you won't get some lens functions due to insufficient power. This is in Video mode, shooting at the highest frame rate for each of the resolutions offered. For example, if you're set to Full Frame sensor mode, recording format set to Cinema RAW light, 8K, and 31-60 FPS, then you will lose the auto-focusing and the aperture will remain wide open. In such cases, Canon recommends using the PD-E1 USB power adapter or the CA-946 compact power adapter. You can also use an Anker PowerCore+ 2680mAh PD with has a USB-C connection. It should be rated at 9V, 3A. You can also use the Anton Bauer Dtap to Canon 9V which would require the Canon DR-E6C DC coupler.

With that said, if you have other lenses that are working in this scenario, then it points to an issue with this particular lens. 

[shadowsports]

Greetings,

I think this points to the lens itself as John_Q suggests if other EF lenses are working.  The EF 24-70 f2.8 II is supported in S&F mode when a Canon brand adapter is used.

The list below are not as of v1.0.6.1

In video mode you cannot take a still photo when S&F is active.  I know you can map a button, but I'm pretty sure no image is captured when this is active.  I'm sure you know you can take a reduced res images in Cinema mode otherwise.  You should not see any errors in photo mode, so again it sounds like a lens issue.  There is no FW for this lens I am aware of.  This lens including the mkII does have a history of ribbon cable failure though.