That looks like it could be Blossom End Rot caused by there not being enough Calcium in place at the time of fruit set.
There are numerous reasons why this happens and maybe this article by Charlie Nardozzi might be if some help.

Here is a link that might be useful: When good tomatoes go bad

Could be late blight. How do the leaves and stems look? Blotchy? They look fine from that picture but if it's LB you'll know soon enough b/c the plants will die within a week.

I've been having a lot of problems this year with BER on tomatoes besides pastes, and on peppers. It's usually right on the very end (I see 1 of your tomatoes on the side) and very black, sunken. Yours are brown - and leathery?

That does make a lot of sense, but the stuff wasn't on the blossom end of the tomatoes in most cases.

This plant is in a large container (I don't have land) and I typically water it daily. How much water would you recommend at that point?

I also added bonemeal on top in hopes that it'd leach raise the calcium levels, but it doesn't look like that'll help.

Here's a link to the original photos, which are larger and should allow closer inspection.

Here is a link that might be useful: Larger Photos

there is a very active tomato forum ...

but here in MI ... i tore up my Ts yesterday ... i am tired of their nonsense ...

i know you are in a higher zone.. but the days are getting shorter [sun is a very important cultural need on Ts] .. cooler days .. nights cold... if not now.. soon enough.. T season is over ...

think long and hard about what it might take.. to solve an issue like this.. this time of year... it just might not be worth it ...

e.g. its not really time.. to use chemicals for something like leaf damage.. on a plant that is past its peak ... i know that isnt suggested here.. its an example of the late season decisions ...

Ts are hot soil.. hot season plants.. [hence the term hothouse Tomatoes] and when you think of it that way.. you should come to realize.. sept/oct... is not ...

so the simple solution... is to declare the season a success.. and throw the plants out ... and start thinking about how to do it better .. next year ... [and since you are growing in pots.. think about throwing out the potting media also .... it doesnt last forever ... and the first problem when it wears out.. is water management ... which seems to be part of your issue here]

good luck ... as all gardeners and farmers say... there is always next year ....

ken

ps: even if you failed.. the season was a success.. because you learned things ...

I still don't know what this is, though, so I didn't learn anything about it. Is it the relatively common blossom end rot? Is it the deadly late blight? Is it something else entirely?

I never got any red tomatoes off this plant, either, and since I don't know what I did wrong, I don't see much good in the situation.

I'd suggest BER.

The calcium "shortage" occurs even if adequate is in the soil. It's a transport problem. In other words, evenly moist soil (or potting mix) must be maintained in order to move the calcium to the blossom end of the fruit..

A pot restricts root growth. Your tomato looks like one with large fruits. Such a plant must be in a *large* pot. Figure on 10-gallon or more. What size is it in?

Bonemeal is a poor choice for a pot-grown plant. That stuff works much better in the ground, where it's in real soil and exposed to numerous microbes.

The center photo shows typical BER at the blossom end. The other 2 images show damage on the sidewall which could be either BER or sunburn.

All this makes me wish I had land. Can't find a place for both myself and my plants to properly take root, but it's too soon for me.

The pot is definitely not that big. I'd guess maybe 7-8 gallons based on the measurements I found and compared online.

I usually water it daily in the mid-afternoon before sunset, so how much should I give it given the pot size? I have a soil test kit on the way to check it out. Any advice on this would be helpful as watering the right amount always seems a bit tough.

Sunburn seems likely for at least one of them as the fruit is getting a good deal of sunlight. Should I cover the fruits themselves in a mesh?

Thank you for the advice. As long as it's not late blight, at least there's something I can do. While I can't rest easy, I don't feel as hopeless.