Mike (and anyone else with an E4):
How useful would you estimate this particular camera is for taking images of PCBs, in enough detail to identify which components are getting warm (with or without the benefit of your recent work)?
For example: last year I borrowed an E60, which has a manual focus lens, and not only was I able to pick out individual 0603 components, but I could also easily see which components were active at any particular time. It would have been a really useful tool for finding out how a board's power dissipation is distributed, or for tracking down failed components on a faulty card.
Shame it's about £6000, though, and there's no way I'd get value for money from it. But £800 for an E4 is far easier to justify.