Why would you ever need to level your camera? Isn’t correcting out-of-kilter shots what photo editing software is made for? I can think of at least two good reasons: One, you’re shooting in film and straightening a crooked shot is a much more involved process; or two, you’re taking video and don’t even want to think about rotating the frame in software.
Slide Opteka’s triple-axis spirit level into your camera’s hot shoe and you can level your camera from left to right and back to front. You use the third axis when you’re shooting with the camera on its side in portrait orientation. Opteka molds the housing from clear acrylic and fills the bubble vials with a contrasting green fluid for easy visibility.
Be careful when you’re buying this level’ they sell two different models depending on whether your camera has a normal or reverse hot shoe. The stated list price is an insanely high $39, but you can find it for anywhere between $4 and $15 before shipping, depending on where you look.