I am having problems with critical optical performance of my Bronica SQ-Ai/PS lens system and finally narrowed the problem down to the vibrations caused by shutter. I do NOT mean 'mirror flap' - What I am reffering to is a critically unsharp image problem even with mirror locked up, and time allowed for those vibrations to subside - due to the heavy mechnism in camera and lenses that trip the actual leafs in the lens. It seems the problem is most pronounced with focal lengths 150mm and longer, and starts at shutter speeds of 1/60th second, but in my limited tests was more likely to be very prononced at 1/30th second. I did testing with a heavy 1300 series Gitzo w/ center column weighted down and Arca Swiss B1 head, and RRS arca style quick plate. Anyone who is familiar with the shutter mechanism knows that it causes vibrations itself even though the actual blades are leaf, very subtle, and not a problem in themselves. The mechanism that trigger these leafs, are pretty heavy duty high tension springs, rapidly rotating levers and a rapid stop there of. When you trip shutter carefully via cable release you can feel the camera vibrate even with the mirror locked up. My question is for any Bronica users who are already aware of this and have addressed it: Other than fastening camera on a steady tripod, using cable release and mirror lock up - what have you done - if anything - to get critically sharp shots at shutter speeds 1/30th and slower? Second question: I only tetsted three speeds 1/125, 1/60/ 1/30 so far - problem was most often at 1/30th and w/ longer lenses 150mm, 180mm, 250mm - especially the 250mm at 1/30th. At what longer shutter speed can one expect the problem of uncrtically sharp iamges due to camera vibrations to be minimized again? Thanks in advance for any knowledgeable or general input on shuutere vibrations on this particular system.