A good camera is handy to have in the field. You can capture in a picture more details than you can sketch in a reasonable time. Additionally, if you sketch like I do, the picture will be far more accurate in its recording of what you are seeing. For instance, the above photo shows Columns of the Giants, from well up into the Sierra Nevada range in California. From this picture, you could estimate cliff height, the height of the columns (at the base of the cliff), the typical size of the columns, and so forth.
One or two lenses are generally sufficient: a wide-angle lens to get big features (choose this if there can be only one), and a macro lens for close-ups.
When taking pictures, it is important to include a scale of some sort. It can be a finger, shoe, pen, hammer, person, truck, whatever. Just make sure there is some context for the size of the image. I was reassured when, in my quest for a scale-less picture for last week’s post, I had difficulty finding one. For many places, you might get by if you forget. However, on Heard Island, the barren and alien landscape will not be so forgiving.