Author’s reward depends on the amount of Vote but not on SP. but your Vote Value depends on SP. its a bit complex for a newbie but once you get the hold of it, you can actually guess your author’s reward even before it is paid out.

I am sure you are already familiar that the sooner you get the vote, the maximum value of vote you will get as an author. For instance if i upvote your post after 1 minute of you posting it, you will get almost 95% or more in authors reward from that upvote.. this will go on until almost 30 minutes to your post, after which you will receive 75% of vote in author’s rewards..

My good friend @ilyastarar, has written an extensive guide on steem reward system and how does it work.. it includes every bit of cacluclation that is involved and all the factors that affect reward system.. here is the Link

If you have any further questions, please dont hesitate..