Mystery Disease

I went to the community garden for the first time in about a week and was pleased to see that it's mostly thriving. However, a quick examination of my tomato plants showed that a quarter of them are infected with something. At first I thought it was just dirt splashed on the leaves, but unfortunately it's definitely not dirt. I'm thinking it's either septoria leaf spot or early blight, but I've not seen this before and would love some help figuring out what it is. The affected leaves are mostly on the bottom half of the plants.

Other than the diseased plants everything is looking pretty good, although I had a ridiculous amount of weeding to do in the right bed. I'm particularly happy with the bean patch and the kale, which have both shown awesome growth and are looking very healthy.

Before Weeding....

And After!

Donated Kale

The Bean Patch

*Update!* After some help from the people over at gardenwebs and a return visit to the garden I have decided that my mystery disease is indeed early blight. I yanked the 2 plants that were most heavily affected and removed all the infected leaves/branches from the other plants. Now I'm just waiting it out to see how it goes.