Could someone suggest places to learn about plate cameras? Or just lenses?

I'm working with dry-plate tintypes. I have a 4x5 field camera, and wonder if I can just get an old lens (something fast) that produces that wonderful old shallow depth of field and whatnot. I also have an unidentified old 8x10 on loan from a friend, also with a slower lens (5.6).

I've tried shooting with my modern 4x5 lenses, but they're just too slow. I just don't know where to start in researching lenses and cameras, and can't seem to find a suitable post on here to that end.

Any help would be appreciated.