Related Clues:

• Spyglass part
• Monocle piece
• Wide-angle or zoom
• Camera eye
• Camera shop purchase, perhaps
• Part of a focus group?
• Glass in eyeglasses
• Bifocal, for one
• Projector part
• ___ cap
• See 23 Across
• Pince-nez part
• ''Telephoto'' or ''contact'' ender
• You see right through it
• Focusing device