There are two websites I’ve used extensively for information about camera bodies and lenses, and in the process helped my own understanding of some underpinning concepts:
www.dpreview.com contains comprehensive reviews and tests of nearly every digital camera made (including tests of dynamic range, as touched on today). Has some limited lens and other reviews too.
www.photozone.de contains a database of many but not all SLR style lenses of the main brands (zoom and prime), with test results that show clearly the apertures at which they excel – or not. Worth reviewing for your own lenses if they appear here.