Not all of them, but Vermeer is a famous one who actually did that. I think camera obscura is a great way to improve the end results of the painting. But thing is, with just that tool you don't get there: it just helps (in my humble opinion) with composition, accuracy. For the rest it is up to the painter, which is not a calling by the way, but a craft. ;-)
Agree.. I think it's a great tool...and you need skill to use it, even assemble it for that matter. The results, between the realistic perspective and the color applications to represent light and shadow are fantastic...and to think they were making their own paint mediums as well! They weren't going down to the art supplies store to pick up a tube of Prussian blue!
Yeah, that is very true. I wish I could go deeper into that pigment making, but that is for when I am using oil-paint instead of acrylics. Slowly I am turning away from aerosols in my little workshop. Partly for the environment and partly for my health. Even with a mask I can get blackouts and have dizziness throughout the job, which is bad. My solution is using airbrushes and a paintgun, which are way more efficient and do not use aerosols except compressed air. :-)
Edit: this is sort of relevant.