Here are three pics from my DIY soldering microscope that I mentioned in comments for EEVblog #282. I'm using Sony EVI-400 block camera. First pic shows the setup, with the makeshift ring LED light that I've put around the block camera. You can see the circuit board that I'm magnifying, with about 6" of clearance, enough for comfortable soldering. There are a number of 0804 and SOIC-8 packages. In the second picture, I've shown the Windows based software used to control the camera. In the third picture, the actual magnified circuit on my 24" Dell monitor. For comparison, 0.6mm solder has been shown. The writing that I've etched there is smaller than 0.6mm. If that can be done, then you can guess that soldering is not a problem. As you can see, the problem that was mentioned in EEVblog #282: camera focusing on the center, but not on the rest of the circuit is not there. Resolution is not very high, but good enough for soldering. You can read the markings on 0804 packages very easily. The package looks as wide as my thumb on the screen, already large enough for easy soldering. The delay is absent with real-time response (30 frames per second).
Total Cost: $0 (everthing from left-over components that I already had from other projects). Otherwise, new SONY EVI-400 is about $360, but old ones are less than $100 from Ebay. You can also buy cameras from other vendors which are using this camera for $60 to $75. Dell monitor which has S-Video input is about $480 new, smaller, older ones are available cheaper from ebay. 12 volts external supply.
Other effort: Had to make cables and trace down the signals.
TODO:
1. Use diffused light. Try better ring light.
2. Connection and control for two RC servos is available on the controller board. Make an x-y stage to move the circuit board.
3. Already ordered 2x tele lens (37mm to 58mm). If that works, the next step is to order 10x lens. Combined with 12x optical zoom for the camera, this will make it into a powerful microscope.
4. I've already tried out connecting the camera to TI's image processing board that I have, which can convert the video output into digital streaming output. Still need to develop decent software for it.