I have a similar problem with my extreme macro because the mirror and curtain create vibration. To minimise vibration I use manual 10s settings and shoot on rear sync by which time the vibes have died. Unfortunately Pentax is very limited when it comes to matters like this for your needs I think. Even if you use b there is still vibration when the b starts. In liveview you actually get 4 mirror movements, lv on, lv off, exposure start, exposure off, it would have been so much better if the middle two didn't flip the mirror. i think you can set the time in a Canon and in decent Canon models and brands that use modern technology like Sony you can also avoid the issue with EFSC (electronic front shutter curtain). Pentax doesn't use leading edge technology.
Last edited by Nass; 12-16-2012 at 07:22 AM.