Problems with Minimatic-S aperture/speed

Welcome to the Forum, tommo61. I think the Minimatic-S uses a trap-needle arrangement to adjust shutter/aperture (which I think are one and the same on this camera). It could be possible the arrangement has been damaged in some form, which might be the reason you don't have any shutter control. And the needle may be a projection, so possibly the display prism could be out of alignment, or missing.

After looking at a Minimatic-C, which is just an older version of the same camera, like a lot of old Yashica rangefinders, the patch is a little dim, but not as bad as the one on my YK. And I was right about the meter needle being a projection, but it is above the viewfinder frame. In other words, as you look through the finder, there is a dark strip that runs along the top of the frame, and that is where the needle is projected against a background of red-clear-red bars that represent the over-okay-under exposure readouts. As I pointed it to a light source, then did a half press on the shutter button, I could see the needle being grabbed. When I shifted the view to a darker area, the needle didn't move unless I released the half-depressed shutter button to free it up again. Sort of a primitive AE Lock.

I really don't see much difference in shutter speed either, though that should be controlled by the ASA setting. Possibly there are a range of speeds assigned to certain ASA settings, but since the shutter is acting in a dual roll as the aperture, that may not be the case. The only reference the instruction manual gives about shutter speed is that when you use the aperture settings for flash, it automatically sets the shutter at 1/30 for the sync speed (using a bulb flash). Over exposure can be compensated for with ND or contrast filters, and under exposures with the use of flash.

For flash you set the aperture according to the Guide Number of the bulb divided by the distance, or GN / Distance = f number Thus a GN of 128 / 32 ft yields an aperture of f4. Distance can be determined by dividing the GN by the aperture. GN is determined by multiplying the f number by the distance (just in case you have a bunch of bulbs of various GN on hand). en.wikipedia.org/wiki/Guide_number

My other Mnimatic-C is in perfect condition, but the one I looked at tonight has issues of the glass window over the ASA dial is loose, and the shutter is a little sticky.

Here is an example of what these cameras can do when they are working correctly:


Pink by P F McFarland, on Flickr

Hope you figure yours out. You might find a copy of the manual at www.butkus.org/chinon/ At least the one for the Minimatic-C is there. I think the difference with the S is it might have a different ASA range.

PF