Sarcanon, I'm honestly, seriously not harping at you when I say this, but I/we get this question ALL THE TIME EVERY DAY FOREVER.
In this forum, the A590 is a proven workhorse. The bottom line is this: If you want to use the USB triggers like other people use here, you must pick a camera that is supported by Stereo Data Maker
. Everything else is graby.
People spend a lot of time handwringing over the cameras. We've had people not build scanners because they couldn't decide on a camera. We've had at least two dozen threads and I've had more than 70 odd emails on which camera to buy. All you need to do is pick from some camera on the list I linked above and you will be fine.
For more detail, and the longer answer I give every time forever all the time, please check this thread. viewtopic.php?f=1&t=332
Since I don't want this build thread to turn into another "What camera should I buy" thread, I'm going to ask that any further camera-related questions go in the thread I just linked. I am in a small community in Northern Ontario right now doing some testing on the Standard Scanner prototype. I have a couple SX200s. If they somehow don't work, I'll report back here by Tuesday of the coming week. Otherwise, please assume they will work and buy the most camera you can buy for the money you have budgeted. Cheers!