One way to protect camera gear when on safari is to place it in a pillow case while driving in the vehicle. Even with the windows closed, the dust is pervasive. When you stop and shoot, carefully take the fabric off the camera and lens. I say 'carefully' because you don't want the dust falling off the pillow case onto the camera.
I photographed the lion you see here with a Canon and a 500mm lens, and both of them fit into the protective pillow case easily.
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Article by Jim Zuckerman. To learn more about photography, explore the many online photography and Photoshop classes offered here at BetterPhoto.com.