In total there are 98 photos in the game, for collecting each of the collections you will get a reward. For the “Memories of Honolulu” achievement, you need to take 30 photos from different collections.
The guide contains approximate locations, as the photo will be marked on your camera when you get close to the specified location. You will be able to start collecting photos after you take the first photo in a story mission (this will be the first photo in the Waiki collection). The order of the photos is the same as the order of the photos in the game within each collection.