Professional gear - the cost of getting 1Kg of cheap camera lens into orbit is the same as 1Kg of professional gear! The retail cost difference is a rounding error.
Onboard the ISS, US use Nikon D4, Russia D3 dSLRs. Sony, Panasonic and Canon cover video duties.
For handheld photography outside the ISS, a modified Nikon D2X is used.
You can often see an arsenal of dSLRs and big lenses fixed (velcro?) to the the walls in interior photographs of the ISS. ThinkPads are also easy to spot.
There was a documentary made with IMAX film onboard the ISS over a decade ago. Because IMAX is chemical film and not a digital format, the film had to be returned to Earth fairly promptly, so that it wouldn't record too many cosmic rays.