While the basic things that you would first put in your bag are your camera, charger and lens, there are a lot of other important things that you may need in your bag. These depend on the level and the type of photography you do.  Apart from the basics, you would also need your camera and lens cleaning equipment with you. Now the number of accessories that you would be keeping in it will dependent on how big of the bag is too. You can also place other items such as extra memory cards, extra batteries, flash or other lighting equipments also. A few photographers also find some space to fit in their laptop or tablet (with charger) so that they can go for quick edits on the go.