Camera won't take picture

[AlanPrather]

Camera will focus when the button is pushed 1/2 way down and seems to do everything it is supposed to do, but it won't take the picture when the button is fully pressed.

[jamesjburke]

Hi Tim:

I found your response to why Canon cameras won't allow users to take the photo very helpful. I am hoping someone can help me with this one. 

Camera:  Canon R5

Lens:  Rokinon 14mm

Attempted shot:  Star photography

ISO:  3200

Focus:  Manual

Shooting Mode:  Time Value

Time:  30 seconds

The lens was securely connected to the lens adapter. The Rokinon was set to F2.8 and infinity focus. But the R5 would not allow me to take the shot. I took the Rokinon off of my R5 and put it on my 5D Mark III and had not problem taking the shots with very similar settings. Any suggestions on what I should check in order to get the R5 to take the shot?

[kvbarkley]

There is a setting which allows the R5 to take an image without a lens.