The MTO 500mm f/8 Grand Prix Brussels is a Soviet-built mirror (catadioptric) telephoto lens, designed as a compact long-focus optic for distant subjects such as wildlife, sport and surveillance. The 'Grand Prix Brussels' designation refers to the award MTO mirror lenses received at the 1958 Brussels World's Fair, and copies have circulated in M42 and other adapted mounts in the decades since.

UK auction activity for this lens is thin: the only recorded hammer result in our data is £30 from November 2025, so both the range and median sit at £30 at saleroom level (these figures are wholesale auction prices, not retail). On that single data point alone it is hard to claim a firm market value in 2026, and condition, completeness of accessories and mount adaptability are likely to swing what a clean copy actually sells for.