How do I beat the challenge scores in Pokemon Snap (N64)?

I started playing this N64 game, Pokemon Snap, for the first time since a few days ago, and I've just captured all 63 Pokemon and reached the end. But now, I'm having real trouble trying to beat any of the challenge scores in the levels…even the first one (Beach).

How is it possible to achieve this, and how the scoring system works when exploiting it? Does it have to be taking the same pictures of Pokemon in larger sizes over and over to get more and more big points? And to "waste" all 60 shots before the end of a level is reached? I currently do not understand how to do all this right…maybe I'm just missing something? =/ The only obvious thing I know that is vital to upping the score a lot (even though I still couldn't achieve Beach's target score, I was SO close XO) is to get many kinds of Pokemon captured for a better multiplier. But even doing that it still wasn't enough to reach the target score.

Sigh… I'm feeling rather upset about this, I just want to complete this game 100% and move on to the upgraded and modern "New Pokemon Snap" game for Switch that seems to look more better (particularly the cover art with Meganium who I really like as a high favourite). May I please know the advice and tips to beating the challenge scores in this N64 original Pokemon Snap game? Also I'm doing this game on the Switch Online membership (which to be fair I am not happy with, because it's subscriptional-based and I prefer owning retro games for real, but sadly Pokemon Snap has major issues on Project64 like control stick not working and photos not being displayed properly in the results screen, and also no red dot present in a level).

Cheers and thanks.