Thank you very much for your answers.
The conclusion I draw ist that it seems very special a toy, and as I never did any motorsports shooting by now it is nothing I really need.
I have alway to remember that I must... not... collect this pentax stuff but use it just for taking photos. I should better go and take some for contributing to PUG than thinking of different viewfinders. BTW, I've already got the FE-1 loupe finder, which I think is quite helpful when doing stills and landscapes, that stuff that lets time to focus and permits the camera to be on a tripod deep enough.
pancho
