Take a look at this shot of the Toadstool hoodoo from Grand Staircase-Escalante National Monument in Utah. The light was really nice – the sky was changing color a few minutes before sunrise, and very soft morning light kissed the orange rocks in front of me. The sun was getting ready to rise over my left shoulder – and the scene was pretty evenly lit, since I wasn’t shooting into the sun. The problem was that I couldn’t capture the entire range of light in a single frame without a Graduated Neutral Density filter… and I didn’t want to use one.
Why not? Well, as you can see, the horizon in this shot is not straight. GND filters are perfect when the horizon is relatively straight. We use them for sunset or sunrise shots – where the sky is bright and the ground is dark. The filter can slide up or down to allow the photographer to adjust for the position of the horizon. They are incredibly useful little buggers if you enjoy landscape photography.
Unfortunately, in this photograph, the line between sky and ground isn’t straight. A GND filter would have made a dark line across the top of the hoodoo. No good. So I bracketed exposures instead. I took two photographs from the same spot – using a remote release to make sure the camera didn’t move at all between exposures. The first shot was exposed correctly for the sky – so the sky looked great, but the ground was too dark. The second shot was exposed correctly for the ground – which meant the sky was too bright.
I used layers and masks in Photoshop to combine these two images and create a final photograph that represents the scene as I remember it.