Hello, this is my first post. A little bit about myself, I'm a 40 something ex pro photographer (15 years ex). My 35mm kit was and has always been Contax 137MA, my original one is still going strong despite abuse after about 20 years of ownership. I also have a 139Q. I've just had my interest in film photography rekindled and am going to be putting my Contax gear to good use again. I'm after a bit of advice, I've recently bought an RTS, it was bought on ebay from USA and sold as non working, it cost me about £30 including postage and turned out to be a mint (and when I say mint, I mean mint! apart from the seals)scientific model whose only fault was the mirror was stuck to the damper foam, now freed and replaced and working fine. To say I'm pleased with the purchase is an understatement. Anyway Google isn't awash with info for this model, are the only differences the shutter button and lock on AE and 60? or do the differences go further? Is the scientific more or less valuable than the standard RTS? Sorry to debut with questions but now I've got a reason to post and not lurk I'll try and contibute where appropriate. Cheers Darran