I'm a new climber, and a pretty lame photographer, but one camera that I do own and love is the Stereo Holga. It's an all-plastic "toy" camera (even the lenses are plastic!) that shoots medium format film (120, instead of 35mm). It takes a fair amount of work to scan and prepare the negatives to print, but I print them out postcard-sized and then look at them through a viewer--which is also a cheap plastic thing. This is super old-timey technology... the two pictures are side-by-side, and you hold the viewer to look at them.
Anyway... 3d pictures of tree climbing are really excellent! Ropes hanging down, your buddy's foot sticking out of the frame, throwbags hanging in the air... cool stuff. By it's very nature, it's hard for me to show you an example here. I'll try to paste in picture to show you.
If anyone else has done this, and wants to swap pix, let me know! Or let me if you want to know more about how I take the pix so you can play too, and I'll write up a thing on how I do it.
I guess the pictures are really in Tree-D!
Or that's about to become my tree name?
Tree-D