I use an Elmo Document Camera. There are some used on ebay. Apparently they are used in schools and are replaced by newer models from time to time. New they are quite expensive, but used are quite affordable. I bought mine for $15 and then bought an old monitor. This is not perfect but gives a nice distance to the part and enables soldering.
There are various configurations of these things that use different monitor connections ( Some HDMI ) and ones with a "stage" for the document (or PC board) and ones that are free standing. Take a look around ebay or other used equipment sites.