In a small town in Iowa, a young aspiring photographer has a 30 days to enter his work into a famous gallery as his narcissistic and manipulative grandfather wants the family farm to retain the honor of it’s name no matter what it costs.

The structure of the logline is working against it.

You mention the goal first and the inciting incident second, best to revers this so the read resembles the order in which the story will unfold in the script.

Secondly the connection between the grandfather's ambitions and the main character's goal is vague. Why would he need to enter his work into a gallery if his grandfather wants to retain the honor of it's name?

The connection between these two events is lost on me as they don't have a cause and effect relationship between them. Best to specify a goal that is a result of the inciting incident as appose to an arbitrary one.