Super 500mm/1000mm f/8 Manual Telephoto Lens for Olympus OM-D E-M10, E-M5, E-M1, PEN E-PL7, E-PL6, E-PL5, E-PL3, E-PL1, E-PL1s, E-P5, E-P3, E-P2, E-P1, E-PM2, E-PM1 Micro Four Thirds Digital Cameras - Walmart.com
Amazon.com : Big Mike's High-Power 500mm/1000mm f/8 Manual Telephoto Lens for Nikon DSLR, Black : Electronics
Opteka 500mm f/6.3 (with 2x- 1000mm) Telephoto Mirror Lens for Digital
Super-powered 500mm/1000mm f/8.0 Manual Telephoto Lens (Black) with 2X Professional Multiplier for Canon EOS Digital SLR cameras and Deluxe Accessory Bundle with Xpix Cleaning Kit - Walmart.com
How an $80 1000mm Lens Performs on a $1,400 Sony a6500 Camera | PetaPixel