Things They Should Invent (or tell us if it already works this way): ranked ballots that you can use to vote for or against

I like the idea of ranked ballots, but I'm not clear on what happens if you don't rank all the candidates. The last Toronto mayoral race had like 60ish candidates, and I certainly couldn't put that many candidates in order!  (And even if you could, they'd have to let you bring notes into the voting booth!)

The way I want ranked ballots to work is to let me rank some candidates positively, and some candidates negatively. If I think Candidate A is the best and Candidates B and C are also acceptable, and I think Candidate Z is the worst possible candidate and Candidates X and Y are also unacceptable, and I have no opinion about the other candidates, I want to be able to indicate that with my ballot.

However, as it stands, I don't know if I can do that. I don't know the ranked ballot handles the candidate I rank last compared with candidates I don't rank at all.  (In fact, I don't know if we're even allowed to not rank some of the candidates.)

What I want is either:

1) I rank Candidate Z 60 out of 60, that makes it clear that I think Candidate Z is worse than all the other candidates and the results are weighted accordingly
 or
2) I rank Candidate Z -1, and that cancels out someone else's +1 vote for Candidate Z.

You should be able to rank all the candidates positively or all the candidates negatively, or any combination thereof. 

You also should be able to vote negative only without making a positive vote, because there could be situations where it's more important to stop Candidate Z from winning than to have any specific other candidate win. 

In my ward's last city councillor race, we had the incumbent, and three invisible challengers.  I couldn't find any information whatsoever about the challengers. If, hypothetically, I had thought that the incumbent was harmful to the ward, I wouldn't have had any way of figuring out how I should vote to replace him.  But if I could either rank him last or rank him negatively, then my ballot could reflect the actual situation.

I can't propose a specific way to modify ranked ballot voting to allow for "against" votes because I don't know enough details about how they work already.  But proponents of ranked ballots should either figure out a way to do this, or, if it can already be done, publicize that fact.