LCD and Viewfinder
Canon 40D has a Fixed Type 3″ LCD screen with a resolution of 230k dots. Both the screen size and the screen resolution is up to the standards of this class.
40D has a built-in Optical (pentaprism) viewfinder. The viewfinder has a coverage of 95% and a magnification ratio of 0.6x. 95% coverage means that what you see in your viewfinder while shooting will slightly be different from the actual image.
Max Shutter speed
Canon 40D can shoot continuously at max speed of 6.5 fps and has max shutter speed of 1/8000 sec.
40D has a built-in flash, and it also has a flash shoe to mount your external flashes too.
Canon 40D features a Phase Detection autofocusing system. The AF system has 9 points to choose from.
Unfortunately Canon 40D doesn't have Video recording ability.
Connectivity and Storage
Canon 40D has a USB 2.0 (480 Mbit/sec) port to connect your camera to other devices.
Battery Canon 40D is powered by a proprietary battery which provides a shooting life of 800 according to CIPA standards.
Considering that the average battery life of DSLR type cameras is 883 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 Semi-Pro DSLR Cameras
Nikon D850 with its 1840shots is the model with longest battery life among Semi-Pro DSLR cameras. Check the comparison of Canon 40D vs Nikon D850 or take a look at Longest Battery Life DSLR cameras list.
Canon 40D Features Compared to Main Competitors
You can download Canon 40D's User Manual here