The Olympus 100-400mm IS lens size is 72mm, please reconfirm the number mark as "ø" (diameter) symbol, if the number is 72, just need to order same 72mm size filter ,thanks. 

67mm should also be stenciled on the front edge of the lens somewhere. If so, then you should be good to go. It should be on the lens because a lens cap can be lost or broken. 

Unfortunately this is for adapting lenses to Olympus' modern digital Micro 4/3 cameras. It won't work with the Pen FT or similar half-frame film cameras, and you most likely won't find anyone making adapters for these. 

Yes 

FD-EOS fit for Canon FD mount lens and canon EF mount camera body. canon 60d is EF mount, so the adapter ring can work with your camera, but you need to check your lens mount. could you pls let us know your lens specific model? service(AT)kentfaith(DO NOT)com, Please note: It is not same between Canon FD mount and EF mount, this adapter ring is only for Canon FD mount lens, please contact us if you want to purchase for Canon EF mount lens.