An endoscope includes an insertion tube having a distal end and an imaging device with a steerable extension. The proximal end of the extension is attached to the distal end of the insertion tube. An endoscope includes an insertion tube having a distal end region and a rear-viewing imaging device at least partially disposed inside the distal end region. An endoscope includes an insertion tube having a distal end cap, an imaging device, and a link that couples the imaging device to the distal end cap of the insertion tube.