Shutter Vibrationgreenspun.com : LUSENET : Large format photography : One Thread
I asked a question a few days ago about my Sinar/Copal shutter. I received a good answer, but the rest of the conversation turned to the topic of shutter vibration. Does anyone out there have trouble with sharpness loss from shutter vibration. If so, what type of shutter do you use, and what steps do you take to minimize the problem.
-- Kevin Kolosky (firstname.lastname@example.org), September 12, 2001
I am assuming that the reference to your earlier thread is in relation to the second point you raised about vibration. Your first question concerning attachment seemed to be resolved.
In the past I worked for several years with the Sinar system and was so underwhelmed by it that I divested myself of it. But when I did have it I looked into the question of the mechanical behind the lens shutter and considered it a lemon ... due to the vibration generated by its operation. Perhaps that vibration may be at tolerable levels for the mass/rigidity of the P2 standard. But on the F2 — forget it.
Added to the vibration factor is the fact that the lens must be mounted ENTIRELY in front of the shutter thereby adversely affecting the centre of gravity, equilibrium and, therefore, stability of the front standard.
The mechanical or physical vibration is amplified by the increased leverage (moment of force about a point) and the optical effect of this increased vibration is further amplified by the distance of the lens plane from the image (film) plane.
Undoubtedly there will be those who disagree with my analysis but the effect of the vibration can be demonstrated by placing a small spirit level atop the lens bearer and watching the bubbles shimmer as the shutter is tripped. If they shimmer after the exposure it doesn't necessarily matter — if they shimmer as the shutter opens it does.
Furthermore, I have had Sinar salesmen point out the benefit of the hexagonal accesory rod for bellows shades, Polariser, etc. being supported at the bottom of the lens panel because there is less leverage down should any vibration be incurred by wind, etc.
I hope this helps. WG
-- Walter Glover (email@example.com), September 12, 2001.
Well the shutter system is designed to be used on a P series camera, but the vibration is still terrible but mostly it occurs as the shutter closes. They also would prefer you use your Sinar camera on the fabulous Foba camera stands (which are great, no sarcasm).
-- Ellis Vener Photography (firstname.lastname@example.org), September 12, 2001.
I'm late with this but here goes anyway:
I inherited a Sinar out where I work. It has a 210 Nikkor W. Never ever got a sharp pic with that camera and never having had the pleasure of owning Nikkor lenses, I blamed it. Finally I took the Nikkor elements and screwed them into an old Polaroid Oscilloscope camera Copal and hung it on the front of the Sinar abandoning the built in shutter. I was blown away with the images the very first try after that! Ultimately I "found" some $ and bought a Toyo 45AX and am living happily ever after. The Nikkor is still in the Polaroid Copal! J
-- Jim Galli (email@example.com), September 22, 2001.