This page describes technologies that can be used for a near-space balloon launch.

Camera/Imaging

Canon Powershot

Using the CHDK project, you can run arbitrary software on the camera's CPU. Project Icarus used CHDK to disable the LCD display and loop, taking a picture every 5 seconds.

The cheapest new Powershot is $150, but these models haven't been ported yet. The cheapest supported Powershot (new) is $270 from Best Buy (which is too much). A more practical option is to find a cheap used Powershot.

Benefits: no microcontroller required, high quality images
Drawbacks: cost

Cheap camcorder

dealextreme.com has cheap digital camcorders (no lcd display or other frills) for $50-$70.

[1]
Cost: $55
Mass: 296 grams

Benefits: no microcontroller required, video
Drawbacks: image quality of stills

Cheap camera, disassembled

We take a cheap camera, like Gus's $25 camera, take it apart, and hook up some simple electronics to take a picture each 5 seconds.

Cell phone

If we are going to include a cell phone anyway, maybe we can use its camera. I think this only works if we can load our own software into the cell phone. Eg, like an Android based cell phone.

Drawbacks: cost

Batteries

non-rechargeable 3V Lithium

Lithium Polymer