This logline seams to describe the first half of a first act. The grandfather looks to the main character for help, but then what? What does the main character actually do? And what does he actually need to achieve?

Secondly in its many iterations this concept has yet to describe a logical connection between the setting, the goal and provide a reasonable stakes level. The dramatic need (to become a photographer) doesn’t seam to match up with the obstacle (mean and selfish grandfather), as the MC can theoretically just do what he wants to do. It feels like the dilemma of choosing between creative aspirations? and an old man’s selfish needs, is more of a B plot in a rom-com than the A plot of a drama film, because the stakes are just not high enough to justify a story worthy problem.

Secondly the chances of someone becoming a world class photographer are so small, it seams like the grandfather would be smart enough to know that after a few years of poverty and frustration the MC will likely come back to run the farm.

I think the story elements do not make up a strong enough dramatic situation that will sustain a film, the writers work is to devise a premise that does just that, and not re word the logline using the same elements. Here are a few suggestion to help you change the concept:

WHAT IF?

The main character dreams of being a professional photographer and took some photos of his dying mother, brother or father on the farm and submitted them to a photographic competition the prize of which is a solo show of his work in the world’s most highly regarded photo gallery in Paris. The main character wins and is offered his own show, which will launch his career as a photographer. But his grandfather, his only remaining family member, is ashamed of the photos and doesn’t want him to exhibit the work. Now the main character has a dilemma and must chose between loosing his grandfather or his dream career.

This dramatizes the first act and adds a cause and effect relationship, now you need a goal to pursue as a result. You could choose wining the competition as an inciting incident and devise a goal that fits or add in an additional plot such as the bank threatens to foreclose on the farm, so the main character must save the farm and at the same time as he must choose between family and career.

Once you have the most compelling goal and inciting incident in place re draft the logline to reflect how they interact and the main character’s action will play out in the story.

Agreed with DPG.

Some great suggestions made above, I’d add that perhaps the stakes could be made even higher if the two characters would already be married.

What if they are both entrenched deep in married life? Mortgage, kids, white picket fence and all, yet both are depressed. An unfortunate reality for many people and possibly a sticking point for audience empathy, this could strike a cored with viewers around the world.

Sure make the main characters suicidal, but if they are family people then their actions will affect other characters in the story not just them selves and in doing so the stakes rise significantly.

When “normal” every day folk enjoy a good flogging and the subsequent sparks of passion, then the stakes will also rise for the audience as they see themselves in the story.