It is easy to get lost in exploring Tears of the Kingdom, but while doing so, you will definitely want to pick up the camera and compendium to get the most out of your journey. If you want to take photos and catalog your discoveries, you will first have to head to Lookout Landing after finishing the opening area: The Great Sky Island.
At Lookout Landing there are a number of quests and NPCs, as mentioned in our previous guide on getting the Paraglider and when to explore. There you will find Robbie and Josha arguing about whether or not to let her go explore The Depths, a new area in Tears of the Kingdom that features another massive area to explore, this time deep below the surface of Hyrule.
Eventually, Robbie will decide to meet you in The Depths, asking for your help in photographing a peculiar statue deep down in the dark. You will need to make your way to the map marker, near Joisin Shrine. You can get to the Hyrule Field Chasm by heading directly south from Lookout Landing and cutting across the grass field. When you arrive, you will see a massive whole with Gloom flowing out of it and some NPCs investigating it.
Feel free to drop down to The Depths, but be careful not to hit the sides or touch any of the gloom. Doing so will result in losing a heart permanently. Gloom damage causes the removal of hearts until you head to a Light Root in The Depths or return to the surface. Once you arrive, follow the notes left by Robbie to his various camps until you find him near a Light Root. Activate the Light Root and then speak to him, once you do so, he will have you photograph a nearby statue. Once all of this is done, you will be in possession of the camera and the compendium!