I keep a lens on, usually the tamron 17-50, 'cause you'll never know when you see a beautiful shot so it's better to be prepared.
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Cameras: Canon EOS 40D | Canon EOS 650.
Lenses: Canon EF 28-135mm | Canon EF 35-70mm | Sigma EF 70-300mm.
Speedlights: Sunpak PZ42X with wireless trigger, stand and umbrella.
Links:
flickr