Ok, what I'm going to say is based on experience not books, I know there's argument/ controversy about this.
You have early blight!
That's scarred tomato doesn't like like the tell tale blight rotted fruit...
The leaf screams early blight to me,
It's tough to deal with, I plant my tomatoes 6 weeks after the local competition.
It helps me avoid the first round of blight and that helps with the late blight for me.
Treatment isn't all that effective, but there's hope, the main thing I can tell you is that it's very easy to spread!
YOU are the most likely way this stuff will spread!
If you walk around the plants much, your boots will spread it, especially if it muddy! And of course reaching down into the plant to pick fruit is a big one and hard to avoid!
Dispose of any affected material the best you can, get it far away!
If you plan to grow tomatoes all season you need to read up and take careful action.
Best of luck