I bought a lens off 'the auction site that must not be named' and when it turned up, the rear lens cap was actually a F90. I didn't need it, but I ran a few rolls through it and really liked it. They are a complete bargain at the moment. I saw one at a camera fair with the rubber cladding falling off but otherwise working perfectly for 15. I'm sure they were close to a thousand pounds new. They are a bit noisy though...