I have tried the 300mm f/4 lens (non-IF) on my Pentax 67 to see the effects, if any, of the much debated shutter vibration. I was cautious to use a heavy tripod (Manfrotto 475B, most likely a former Bogen) and a small but quite strong ballhead (PhotoClam). A dedicated plate was used to connect the camera base to the ballhead. Instead of a bean bag, I have used my camera bag to damp the dreaded vibration. Other than these precautions, I have not done anything systematic or scientific! The film was a Fuji NPS 160 (4 years past its use before date). I have treated the film as ISO 100 to compensate for its age. The aperture values were either f/5.6 or f/8. The shutter speeds were between 1/4 and 1/30 second. MLU was used in all the shots. Under these conditions at least, I was unable to detect any sign of vibration by examining prints and the film. However, the prints were relatively small and I did not magnify the film more than 8 times. All I can say is that the lens is perfectly usable under the above conditions. A sample is attached. It is a resized version of the Epson V500 scanned original image.