I recently picked up a Mamiya C3 and 65mm lens with the hope of using it for a bit of Street shooting as it has a 65mm lens which is approx 40mm ish in 35 mm terms.
I shot a trial roll of expired Ilford Delta 3200 in poor light it must be said  to see what I got and after scanning the negs I got 12 frames all out of focus mainly back focussed.
I put it down to wide apertures/slow shutter-speed and not a very bright viewfinder.
Next I tried my last roll of Delta 3200 but this time on a tripod in better light and to my horror they were all back focussed just like the 1st roll.
After a bit of advice I checked the lens were mounted flush and also removed the focus screen and noticed that it had 2 quite thick card shims propping up the front of the screen. So I removed one of them and the screen seemed to sit a little more flush to the body.
All these images were shot using this configuration on Ilford Delta 400 and even though they were not all totally spot on they were far better than the 1st 2 rolls.
I may remove the other shim and replace with a slightly thinner one and see if it works.
I love using this camera it is a lovely piece of kit and hopefully I can get some good images eventually 🙂
tim dobbs photography 