Candid with D50 and Sigma 18-50 2.8 - she was wrapped up in her work and the shutter was quiet enough not to disturb her. Focussing was also very quiet, even though it's not supposed to be a silent motor.
I had my lens review 90% written and then lost 2/3 of it to a freak cut n' paste error - that'll teach me to compose really long stuff in Blogger.
Overall news is positive - all my lenses seem to work at least as well on the D50 as they did on my old film cameras. The detailed stuff will have to wait until I can find a couple of hours to write eveything up again. Maybe next week.
I've posted some focus tracking tests on Flickr - they might not make too much sense without the text, though.