How does Jim Egan know about camera obscuras? For 40 years, Egan has been an in-the-trenches guy: a professional photographer, spending hours viewing upside-down images under the dark cloth of 4x5 and 8x10 view cameras. He has built dozens of pinhole cameras, camera obscura rooms, and even a camera obscura building. Plus, he's written ten books involving Renaissance optics, mathematics and architecture.