Canon's c100 camera and Sigma lenses
 

In having read a few threads on this forum, other lenses (third party), other than Canon, will work on the c100 camera, as long as it is EF compatible. During a shoot today, I attached the camera to a Sigma 120-300 ef lens. The f-stops disappeared from the info area of the viewfinder, only showing -- in place of where the f-stop number should be. I used this lens on my 5DMRK III to shoot stills and everything was fine. It is a newer OS version of Sigma's 120-300 f/2.8 lens. Not the newest, but new.

Is there something I am missing? I had to control the aperture via the shutter speed dial and ND filter. So I was one-stop under or one-stop over in exposure. I just assumed all ef compatible lenses would show up in the info area.

Thanks for your assistance.

Jerry Mennenga
Sioux City, Iowa