It's generally not a good idea to squander the more powerful film types as soon as you get them, such at the 61, 90 and Zero Types. Budget your film rolls very carefully, saving the more powerful for boss fights and tight situations.

07 Type / This film is unlimited, but very weak. Use this to take environmental shots, key photo shots and to fight weaker ghosts or ghosts you have plenty of space and time to maneuver around.

14 Type / This should be used inside houses for weak to medium strength ghosts, depending on your situation. If you're in a sticky situation, or confronted by more than one ghost, it's best to pick a Type up.

61 Type / Use only in later chapters if there's a particularly strong or clever spirit attacking you.

90 Type / This should be reserved only for the last boss encounter.

Zero Type / This film is extremely rare, so use it only as a last resort for the final boss encounter if you run out of Type 90. If you have none of these last two types left, it will be virtually impossible to finish the game with only Type 07 film.