Thank you again for all your useful comments. Regarding the red window, my camera does not have the red filter, just a hole (it lack also all the letherette of the back). No light leak. Nevertheless I have found my method usable, even with a red windows provided the light source is good (a 100 W table lamp is ok) and a fast SLR lens (2.8 is OK). I think it is the same method as the Rick Oleson. The difference I found it is not between with or without back paper, but between film and a rigid ground glass.
In this lens you can not change the position of the frontal lens to collimate it, because the ring that support it is retained by 3 screws, not in the lateral of the lens, but in the frontal part, with holes in the lens mount. So I just added shims to get infinity focus ( a lot of them i must say).
It seems to me that the problem of the camera is not related with bad collimation: there is nothing in focus in unsharp pictures. The pictures I posted are taken with the same lens in the same position (I refer to the relative position of the frontal element). Both in a tripod, cable release. The films are Tmax in rodinal and foma 200 in ultrafin plus. I know, very different, but this can not account for the sharpness difference.
All the photos I took with the SLR are acceptable, even using the frontal element to focus, so it is not the lens, the lens is sharp. I wonder now why I didn't use the compur in some shots, instead of the focal plane shutter, to see its influence. I am now a little tired of tests to repeat it!.
When I bought the camera the focus ring was very stiff, and the shutter completely dead. I cleaned all the grease, and didn't put any in the helical, so it was really very free, but I didn't think this could be of any influence. The compur rapid in really very strong, enough as I said to move the ring sometimes.
I have put another roll in the camera, with the frontal lens play corrected. I have also tried to improve my handholding technique. Next weekend I will develop and post some results.
Thank you again for your time and interest. This discussion has been very useful for me!!.
Javier
