Related Clues:

• Slide projector part
• Word with contact or zoom
• See 22-Down
• Bifocal, e.g.
• Telescope part
• Crosshair setting
• Part of S.L.R.
• Refraction producer
• Cinematographer's concern
• Rainbow maker
• Telescope piece
• Light refractor
• Microscope part
• Rainbow producer
• Contact, e.g.