Beginner Gardening: What is wrong with my tomatoes?, 1 by cabrlamo

cabrlamo wrote:
We planted two varieties of tomatoes Opalka and some heirlooms. The opalka have this odd brownish color at the bottoms. It looks like fungus or some type of blight that has gotten to the majority of the tomatoes. Can anyone offer any advice or maybe identify the problem?

The plants are otherwise very healthy and growing well. I have never seen this before. Are any of the remaining tomatoes save-able?