Hi Everyone! NEW to this forum and need some help with my Canon AV-1 camera and lens. Just bought a second hand AV-1 (everything is working fine with a new battery) and bought a Canon FD 35-70mm F3.5-4.5 Lens. Once the lens is mounted on the camera, I set the lens external aperture ring to a specific F-stop and nothing happens within the lens. I have also take the lens off from the camera to manually check that the aperture is working (via YouTube tutorial). By testing is manually, I can confirm the aperture is working at the various F-Stops. Would be so grateful for any comments or advice on this matter. Thank you!