This is the scope/camera combination I use for wide field imaging now. The imaging scope is a Pentax 100 f/4 (400mm focal length), with an FLI ProLine 16803 camera, filter wheel, and Astrodon filters. The guide scope is a Pentax 75 f/6.7 (500mm focal length), with an SBIG ST-402 camera. They are currently mounted on a hand-crafted (!) tandem bar, but I have Robin Casady parts on order.