The issue of Sinar Auto Aperture shutter & vibrations, is of great debate(reviewing the history of the forum). For my self( and for any body who will agree with me, or any potential user of that shutter), I found a simple way(this is what I think) to reduce vibrations, even at an extreme situation(bellows draw of 72cm). Simply put, the Sinar Auto Aperture shutter, need to be fit with new resilient rubber strips(DON'T REMOVE IT), or just put your own fresh rubber pieces. The discussion(URLs & details) below, is directed mainly toward potential & new users of Sinar Auto Aperture shutter.
If you find me wrong, please correct me.
Appreciating any discussion.
________________________________________________________________________After reading the responses here(very informative), I really found my self trapped more in the same corner. Could the shutter causing problem that I could not see? May be!
For that, I searched in the forum, but unfortunately the situation is turning to be more complicated.
One of the threads I read, was this: http://www.largeformatphotography.in...tter+Vibration (Posts# 3,11,14 & 15). The debate there(like other threads), was confirming to me that buying a Sinar Auto Aperture shutter for outdoor photography, is a pure mistake. But, I couldn't notice any problem of vibration with my shutter for almost one year.
Through that thread, I knew there are two rubber strips, almost filling the two vertical grooves of the front face of the shutter. See please, the (convex and resilient) rubber strips on the vertical dimensions of the squared front face of the shutter: http://www.sinarcameras.com/file_upl...shutter_kl.jpg
There function, could be absorbing the vibration created by shutter movement. Some of the posters there, advising to remove them, to be able to put the shutter on the front standard easily with its clip(which hold the shutter in place) is closed down.
My shutter has also rubber strips, and I can put the shutter on the front standard after two trials, only(most of the time).
No need to remove the rubber strips. I remember the first time I took out the shutter. It was very hard. Later, this process became easier. I noticed the rubber strips surfaces turned to be concave and looks not resilient any more. This is the effect of pressure against front standard for long time.
There is another groove(but empty of rubber) in the rear face of the front standard. It is similar to this: http://i15.ebayimg.com/05/i/07/70/14/7c_1_b.JPG
After this brain storming, I thought: Why I do not try to add few rubber pieces(for more absorption of vibration) in that groove & see if the clip(which hold the shutter in place) will close down?
I ended by adding 12 small pieces of rubber, distributed along the four sides of the groove. Even, the shutter can be fit easily & securely on the front standard.
The rubber I used, are of small dimensions(1.5X3mm each), just fit into the groove of the rear face of the front standard. Actually, they are rubber letters used in personal stamps. See the letters plate, beneath the tweezer: http://www.media-land.net/images/art...0/043800A1.GIF
To see if the rubber pieces have done any thing to reduce the vibration, I performed the same primitive test(slice of paper test) I mention it in my first post. The result, was great. The vibrations was reduced dramatically.
I think, any body using this type of shutter(or similar), should consider the following points at least(plus factors of un sharpness out side the shutter issue):
(1) Loose knobs(chick all knobs of the camera before exposure & tighten them again).
(2) Cable release(any excessive movement of the cable release, can be transmitted via its knob to the camera).
(3) Mechanism of releasing shutter(advance/push the cable release slowly, with no interruption, till maximum & hold it there till the shutter close again. Then release it).
(4) Rubber strips(change the rubber strips when become old and not resilient).
(5) Shutter itself(still un avoidable amount of vibration. Can be reduced by considering the above mentioned points).
I appreciate any correction or discussion.