What's up with my tomatoes?

This is just one picture of the issue that's cropped up on many of my tomato starters. Initially thought it was black spot, but the description doesn't quite fit. There's a mild leaf curl, and the leaves start getting necrotic at the tips. Not much yellowing otherwise... Started on the lower leaves of each individual plant, and slowly worked its way up. On the guy in the picture, I trimmed all bottom leaves, so it's just a stalk with top leaves (which are still spotted). Any thoughts?

Wish I could see the roots. Many times when you see issues along the leaf edges it can be related to a fungus or disease in the roots.
If possible look at the roots, should be nice and white.
When you see off colors or brown you have root damage.
If it smells off you can also have root damage.

Why not start at the cornell university site to identify this.
http://vegetablemdonline.ppath.cornell.edu/DiagnosticKeys/TomLeaf/TomLeafKey.html

Salt damage? I don't think so, but salt tends to effect the tips of the leaves first.

The little fella looks like he could use some nitrogen. Tomatoes are N pigs. Pee pee water . . . a little manure . . . coffee grounds . . . you want your tomato plants to be dark green.