To test the resolution of your camera, here is a test chart that you can print.
The Cannon Powershoot A590 offers a good mix of features and low price that we know of. If you are interested in purchasing a cheep and very functional camera for bookliberating, these recently retailed for ~$99.
- Ability to set the focus manually,
- Option for external power with a conveniently side-located plug (with third party power adapters selling for less than $15),
- 8 Megapixel resolution.
While the Powershoot A590 is one of the only cheap point and shoot cannon cameras to offer manual focus as a standard feature, many other cannon cameras can be given the feature thanks to the good people building CHDK. CHDK is a free software firmware add-on that you can run from your SD card without having to replace the factory firmware. Depending on what model of canon you have, CHDK adds a number of features from manual focus to raw picture support, a related project StereoData Maker also adds the ability to trigger the shutter using a USB remote. If you use CHDK for your BookLiberator, please let us know, we'd love to hear about it.
I can confirm that manual focus works with the Powershhot A470 using CHDK. The instructions in their materials could be clearer though. In the CHDK menu you need to turn the first option “Disable Overrides” to “On”. That will let you set the “Override Subj. Dist. V” and the “Value Factor” option under it. I left the Subj. Dist. V alone and just set the “Value Factor” to 10mm, this is the increment that you will then be able to control the focus in. Once that is all set up, simply change to the PhotoM option on the camera shooting dial and the left and right control cross/d-pad buttons should zoom in and out.
The A470 (and other Canons too) can be set to automatically load the CHDK firmware when you turn the camera on. We're looking into custom CHDK builds that will handle focus and white balance and such.
Simple point and shoot camera that I happened to have around the house. No special features that would make it particularly suited to book ripping. In particular, it has an autofocus that has to run for each shot, which adds a couple of seconds to each page turn.
Still, it worked just fine until I discovered the Canon A590 and it was able to achieve page rates of around 600 pages/hour even with the autofocus.
For best results, use the 10 second timer so you have time to move your hands off of the camera and let the autofocus work. Using it with another camera that either has a manual focus or a shorter shoot timer will help speed up ripping by letting you start the Nikon's shoot clock and then trigger the other camera.