Frames per second capabilities cameras currently installed in Modern Telescopes?
The types of sensors that are used for "Lucky Imaging" can work at frame rates easily capable of sampling changes in the speckle pattern due to turbulence in the atmosphere; 50 Hz is certainly possible.

The detectors used are electron-multiplying CCDs and are available on a number of telescopes around the world.

A video camera can of course be put at the focus of any ground-based telescope.

Such devices are not usually put on space telescopes because they have no need to deal with a turbulent atmosphere. Space telescopes are usually concerned with taking pictures of very faint objects, where minimising the readout noise of the device (to a few electrons) is a priority, and necessitates longer readout times - often tens of seconds.