Venera 7 lasted 23 minutes before failing (although landed in an awkward orientation due to parachute failure).
Venera 8 transmission for nearly an hour, but wasn't equipped with a camera.
Venera 9 operated for 53 minutes, had issues with the lens cap so only took pictures from one of the cameras.
Venera 10 operated for 65 minutes, same lens cap issue as above.
Venera 11 operated for 95 minutes, and Venera 12 operated for 110 minutes. Neither of these successfully released their lens caps.
Venera 13 managed 127 minutes, and both lens caps deployed.
Venera 14 which had the same design as Venera 13 only lasted for 57 minutes. Its lens caps deployed, but one landed directly underneath the surface compressibility tester arm, and returned information for the compressibility of the lens cap rather than the surface.