Norman Koren is a photographer/engineer who founded Imatest, a company that produces what is now the most popular software for testing digital image quality.

This is his personal website, which has a host of tutorials some of which are very technical on all manner of subjects, including monitor calibration, digital vs. film etc. - and all the other things we debate on a frequent basis

Of course there are some stunning images as well.

It's worth a look!

http://www.normankoren.com/index.html