Did the upper left screw head break off and 'play' around inside?
Dan
Did the upper left screw head break off and 'play' around inside?
Dan
on the RHS picture the rim is dinged, not on the LHS. Deduction: front bit of shutter came off and hit deck.
the lens and board were off the camera. Deduction: the lens was being changed in some way.
the shutter appears to have sheared nicely. Deduction: torque was applied.
the lens was on a board. Possibilities: torque was being applied to remove lens from board, attach to board, or in changing lens cell. Probability favours gradual increase in torque in attaching, and shear plane in front of board makes this unlikely, hence removal of "stuck" lens or lens cell more likely to lead to lethal force application.
Shear plane is just at Front of lens board. Deduction: lens cell more likely to be source of torque.
Envisaged scenario: lens and board removed from camera, aim to change lens cells. Twist, snap, horror, drop, ding.
"In the field of observation chance favours the prepared mind" -- Pasteur
If it was a metal board the pin would break off and could deform the back of the housing. Making the use of the aperture hard to move.Originally Posted by Gem Singer
If it was wood the lens board would have a score mark in a arc where the pin is located.
Richard T Ritter
www.lg4mat.net
Richard,
I am well aware of the effect of un-screwing a shutter from both metal and wood lens boards while the index pin is in place.
That's why the first thing I do before mounting a shutter on a lens board is make sure that the index pin has been removed.
I don't like making holes in lens boards to accommodate index pins.
Judging from your pictures, it appears that the shutter was dismantled by someone who didn't know what they were doing. Springs,screws, and small parts are missing.
I think it was used onone of the NASA missions and became detached from the camera during a spacewalk. After orbiting the earth for a few decades it re-entered the atmosphere and broke apart during re-entry.
p.s. the fact that large format cameras are used by NASA during space missions is a very very very highly sensitive piece of information, so please don't repeat it in situations where the wrong people might hear.
Richard,
On the left we see the back interior of the Copal shutter with the shutter blades in place, the plate that retains the shutter blades is in place but the diaphragm blades and everything behind that missing except for a portion of the body casting. On the right we see the diaphragm control disk (silver) and part of the shutter body casting (black) that has broken away.
The bad news is that Copal does not supply replacement body castings - so this is now a parts shutter.
The Copal body casting is brittle and it is not unusual to see one where the rear shutter threads have been broken off right at the base, likely due to serious over tightening of the retaining ring.
In this case the shutter body broke in the flat areas inboard from the rear threads. This leads me to believe the lens shutter experienced sideways torque of a type that would effectively "pry" it apart. I don't see damage to the diaphragm control ring so it was probably not a case of some misguided person literally prying the lens off the board. Instead an event occurred where the unit experienced a sharp strike to the edge of the lens board, a fall to a hard surface perhaps. Then the sudden deceleration of the heavy front element on the lens provided the torque to snap the body casting.
It is hard to tell in the little image, but I also observe the broken edges of the casting appear black rather than sliver or gray. This leads me to believe the casting was weak at the break points and is black because porous areas were infiltrated by anodizing solution when the shutter was coated. This suggests a more modest blow one would anticipate have been needed to break the shutter along the line of weakness.
Great puzzle. Thank you Richard!
I get the feeling from the fracture all around, that it was a crushing force. Something very heavy landed on top of it while it was sitting on something very solid.
I can imagine two scenarios: You were out in a boulder field and a rock just missed you but landed on the lens. You set it down for a moment and forgot about it until you heard the thunk as you drove right over top of it.
Whatever the cause, they sent it to the right guy for repair!
David Silva
Modesto, Ca
Personally, I believe the photograph on the right is part of the solution. Now let me see if my Sherlock skills can solve this riddle....
It is quite obvious the image of the stream was taken in VT's White Mountains. From the angle of the shadows, it can be determined this image was taken in the fall, late one afternoon. A very careful review of the photograph indicates the presence of moose in the area. From these clues, it is most obvious that a moose must have scared the photographer who, reacting in horror, dropped the lens causing the trauma described by Photomagica above.
Richard, you can hold the print until I see you in a couple weeks :-)
John you were 20 feet behind me when the photo was taken.
Richard T Ritter
www.lg4mat.net
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