I shot a roll of 100 (maybe higher) speed film and was using the meter on the Minolta XD 11 SLR. When I put this roll of ADOX CMS 20 into the camera, I forgot to adjust the meter. With a bit of recovery in LR, some decent images resulted. Even with the extreme underexposure the grain is not all that visible (at least from afar). I used the Minolta 50/1.4 lens.
