FA50 disassembly and infinity focus adjustment - PentaxForums.com
Lens teardown videos are hugely compelling
Rokinon/Samyang 50mm F1.2 lens - disassembly and cleaning | FujiX-Forum
Amazon.com : Neewer Camera Lens Openning Repairing Tool Kit Includes: 10-100mm Lens Repair Set with 3 Tips, 6 Screws and 2 Hexagon Wrench for Canon Nikon Sony Olympus DSLR Camera : Electronics
Canon PowerShot SX200 IS Lens Disassembly - iFixit Repair Guide