Get close to the walls. Look for leading lines and pleasant curves, both in the shape and in the coloration of the canyon. Finding a foreground, a mid-layer and a background will make your shots more interesting and give them depth.
Typically, the best slot canyon photos are those that do not include direct sunlight (no sunny walls, no sky) – look for the soft glow of indirect light instead. That means you’ll often want to frame your images horizontally rather than vertical, to ensure you don’t have any sky at the top of your image. The reason behind all this is that our camera sensors aren’t yet powerful enough to be able to manage the contrast between direct sunlight and shaded canyon walls – meaning you’ll either completely blow out the sky, or lose lots of color and details in the shadows. A good image has well balanced-light, and the easiest way to achieve that balance in a slot canyon is to stay in indirect light.
There is a notable exception to the ‘indirect light’ rule: if you are chasing light beams. Light beams can be ethereal, but require just the right air (dust) and wind conditions – human interference can help if the air is calm.
There is no one right or wrong time to photograph a slot canyon. You’ll see different walls and corners light up at different times of the day, depending on the aspect of a canyon’s twists and turns. The general rule, though, is that early-to-mid morning and mid-to-late afternoon will offer you the best chances of capturing magical, soft light. Avoid the harsh light of high noon where the sun is directly overhead, unless you know that the canyon you are visiting has the opportunity for light beams. During the summer months, Peekaboo Slot Canyon just north of Kanab has some beautiful beams in a few spots that you can typically observe between 11am and 2pm, while an earlier morning or later afternoon visit to Peekaboo will allow you to capture that magical canyon glow.