The Stirn L'Invisible is a late-19th-century concealed detective camera made in Germany, designed to be worn beneath a waistcoat with the lens protruding through a buttonhole to take circular dry-plate exposures. It was marketed as a covert photographic device rather than a general-purpose camera.

Auction evidence for the L'Invisible is extremely thin: the only recorded UK saleroom hammer result in our data is £800 from 2014, which sits well below retail dealer asking levels for comparable Victorian detective cameras. With just one verified hammer price on file, the wider value range in today's market cannot be reliably stated, and what a Stirn L'Invisible is worth in 2026 will depend heavily on completeness, condition, and which specific size variant is offered.