I have a Kodak Retina Reflex III with a 50mm f1.9 lens. I know about the bayonet fitting on the f2.8 lens but the f1.9 lens has a thread (as does the 135mm). Can anyone tell me what size this is? I have read various web pages which refer to it as a 60mm thread but my measurements show it to be closer to 58mm. Also, whichever size it is, will it be a standard size or is it a Kodak special thread? Steve.