That's what it looks like to me. Here's a link with photos:

https://www.google.com/search?q=late+blight+on+tomato+leaves&source=lnms&tbm=isch&sa=X&ved=0ahUKEwj3uNzOvKDiAhXlxlkKHdrWCxQQ_AUIDigB&biw=1613&bih=772&dpr=1.13#imgrc=9fQ33hu5rmB28M:

I agree width cindy. But, I can't tell between late or early blight. I've taken closeup pictures of both sides of several leafs and compared them to examples like the link above.

I've done a lot of work trying to get rid of what I simply call blight. I've tried Caliente 199 mustard and a combination of that with letting the ground go dormant for two years. That worked somewhat, but the blight only started later in the 3rd year and wasn't as bad after two years of no tomatoes.

My garden wasn't big enough to rotate crops so I tried rotating gardens. I found a spot where for two years I had no blight and the third year was a minor problem. Another new spot near that one had blight the second year. This year I'm expanding to a garden that is big enough so that I don't have to grow tomatoes or other night shades in the same spot for 3 years.

I have found that when I put too much manure in the soil the tomatoes grew 12 feet high and outgrew the blight. Last year I experimented with setting out tomatoes as much as a month late, to get a big late crop. I did get big crops of tomatoes starting in early September, but I also noticed that the blight started later. It appeared to me that the blight, I get, doesn't blow thru the neighborhood or isn't caused by weather conditions. Seems like MAYBE it's a combination of one of those and the life cycle of the plant.

I need to point out that I grow heirlooms and that I'm not going to change to tomatoes that I won't like the taste of. I'm trying to find out how to grow the tomatoes I want to eat.

Yes, it looks like it on the leaves. Has it spread to the branches and fruit? It spreads fast.

I sprayed with a fungicide the same day. They look good so far.