Snagit is the easiest to use, most powerful, best documented and most economical capture program I have found. It captures everything from a small area of a screen to a full or scrolling screen or short video. It can even capture steps of a process as you execute it and assemble the steps into a quick guide with numbered and captioned steps. There are plenty of tools to edit and enhance the captures. It is a dream for technical writers or anyone who needs to produce job aids. It is available on both Windows and Mac.

The ease of using the screencapture as both a still image and a video

No such in mind at the moment. It seems like even this form dont work properly