Essentially, the stars represent the rarity of the action or pose of the Pokémon when you took its photo. A 1-star photo means that the Pokémon was exhibiting its normal behavior or not doing anything exciting, whereas a 4-star photo represents a shot that captured an unusual or unique action.
In order to fill your Photodex, you must take a total of four pictures per Pokémon: a 1-star photo, a 2-star photo, a 3-star photo and a 4-star photo. To complete your dex with the least amount of effort you should always submit a photo of a star rating you have not obtained yet, with priority shown to higher star ratings. In the pictures above, you can see that the professor has rated no other 1-star photos of Beautifly. Liepard, however, already has a 2-star photo catalogued and can be seen when previewing a 2-star photo taken during the adventure.
You will notice that the color of the stars will differ based on your culminative photo score (discussed below) with bronze, silver, gold and diamond being available. Completionists will probably feel motivated to have each Photodex page filled with four top-rated photos.
Understanding and increasing photo scores
Photo scores are determined by six factors, which we’ll break down below:
Pose: This score is based off of the action you caught a Pokémon performing. Photographing a Pokémon while it is in motion often raises this score. A higher star rating does not influence this, it is more individualized to the specific photo.
Size: This score is determined by how large the Pokémon is in your photo. To increase it, focus on making sure that you’re zoomed-in if the Pokémon is far away or getting the Pokémon in the frame if it is large.
Direction: This score is calculated from where the Pokémon is facing, with higher scores for shots that have the subject facing you. You can try to get a Pokémon’s attention with the help of your scanner, fluffruit or illumina orbs.
Placement: This score is determined by the positioning of the subject Pokémon within the photo. When taking photographs, try to aim the camera reticule in the small boxes that appear on a Pokémon.
Other Pokémon: If you can capture other Pokémon within your photograph, you’ll earn bonus points. You may be able to attract multiple Pokémon through the use of your tools.
Background: These bonus points can be earned based on the landscape in the background of your shot.
One thing to understand about New Pokémon Snap‘s rating system is that you’ll often disagree. Unfortunately, the programming is not good enough to emulate a human’s discerning eye (and that’s really no fault of the developers).
If you are having trouble achieving a high enough score to get diamond stars, the following may help:
Reach higher route research levels, this can influence Pokémon’s behavior and you may find new actions to take pictures of.
See if the Pokémon can be photographed in alternate routes (night, etc.).
Try the scanner, fluffruit and illumina orbs individually to see how the reactions are rated by the professor.