LCD and Viewfinder
Pentax 645D has a Fixed Type 3" LCD screen with a resolution of 921k dots. Both the screen size and the screen resolution is up to the standards of this class.
645D has a built-in Optical (pentaprism) viewfinder. The viewfinder has a coverage of 98% and a magnification ratio of 0.85x. 98% coverage means that what you see in your viewfinder while shooting will slightly be different from the actual image.
Max Shutter speed
Pentax 645D can shoot continuously at max speed of 1 fps
and has max shutter speed of 1/4000 sec
Unfortunately 645D doesn't have a built-in flash but it has a flash shoe for mounting external flashes.
Pentax 645D features a Phase Detection autofocusing system. The AF system has 11 points to choose from.
Unfortunately Pentax 645D doesn't have Video recording ability.
Connectivity and Storage
Pentax 645D has a USB 2.0 (480 Mbit/sec) port to connect your camera to other devices.
Pentax 645D is powered by battery which provides a shooting life of 800 according to CIPA standards.
Considering that the average battery life of DSLR type cameras is 910 shots, its battery life is about average in its class but it would still be wise to invest in some spare batteries for long photo trips.
Battery Life Comparison in Pro DSLR Cameras
Nikon D3X with its 4400shots is the model with longest battery life among Pro DSLR cameras. Check the comparison of Pentax 645D vs Nikon D3X or take a look at Longest Battery Life DSLR cameras list.
Pentax 645D Features Compared to Main Competitors