You can now view photos taken with a certain lens.
for example:
http://www.pbase.com/cameras/canon/ef_28-70_28u
the lenses are listed in the camera database:
http://www.pbase.com/cameras
they are also linked from the technical info if known.
you can't search by f-stop yet. hopefully someday.
The lens data is still crude. Many duplications and missing lenses.
Canon, Nikon, and Sigma are mostly up to date, and I'll gradually clean up the rest as I've been doing with the cameras.
Because the majority of camera bodies are set automatically from EXIF data and lenses have to be updated manually, there is far more data for bodies than lenses. also the majority of cameras have built in lenses.
8.5 million images have their camera set, while only 46000 have lenses set.
Maybe with the recent improvements to batch updating, more people will specify their lens.
-slug