Camera cocked uncocked?

[colin_d]

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This could relate to digi and analogue cameras but I read recently that you should store your camera with it oncocked to save the shutter spring. I assume this means leave the camera ready to wind on for the next shot when you put it safely away for the night, or week.

 

I must admit this is something I never did in the past and it never seemed to affect my shutter action, as far as I could tell. Is storing the camera cocked and ready to fire a big problem absolutely to be avoided or are the tolerances in the build enough to let it happen occasionally without any detriment?

[tobey bilek]

Since they are made for a motor drive, they can remain wound for the next exposure sans motor or with.

 

I personally take the safe route anyway.

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[andybarton]

My dealer always has his used stock on the shelf un-cocked.

 

However, as far as I can tell, the springs on traditional Leica shutters are strong enough to take the strain of remaining cocked. I suspect that Copal shutters are similarly robust.

 

 

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[lars_bergquist]

My dealer always has his used stock on the shelf un-cocked.

 

However, as far as I can tell, the springs on traditional Leica shutters are strong enough to take the strain of remaining cocked. I suspect that Copal shutters are similarly robust.

 

 

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The shutter springs of M film cameras -- and, I would think, any camera using a variant of the classical Barnack shutter -- are wound to a small fraction only of their maximum 'stroke'. So the difference in tension between the wound and the unwound state is not great enough to warrant any worry. Besides, the springs are never entirely tensionless either -- they are partially 'pre-wound' when installed.

 

I think this concern is a carry-over from the Compur style leaf shutters. These are very compact mechanisms, and the coil springs that power them are tensioned to a far larger fraction of their total power. So in this case, it is a good idea to store the camera with the shutter un-cocked. This may not necessarily apply to modern leaf shutters; spring steel metallurgy, heat treatment etc. has improved very much over time, so that modern springs are far more reliable than they were even half a century ago.

 

The old man from the Compur Days

[cbretteville]

Leica literature states it does not matter whether the shutters are wound or not during storage. It is recommended that the all the speeds are worked from time to time to avoid sticky gears.

Carl

[pico]

The M7 uses electro-magnets to drive and stop the shutter.

Does the M9 have the same?

[lars_bergquist]

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The M7 uses electro-magnets to drive and stop the shutter.

Does the M9 have the same?

The M7 shutter is electronically controlled. This means that the second curtain is held back by a small solenoid. The shutter is driven by spring power, just like with any other film M.

 

The curtains are mechanically stopped, also in the classical M manner. No need to use either magnets, smoke or mirrors ...

 

The 8 and 9 cameras use a Japanese-made electronically controlled metal shutter. But believe it or not, the driving power that makes the curtains move does still come from springs. Here, I do not know how you would go about storing the camera uncocked, because the shutter is automatically re-cocked after release. You can delay this re-cocking ('discreet shutter release') but not inhibit it indefinitely.

 

The old man from Compur Days

Edited September 17, 2010 by lars_bergquist

[pico]

The M7 shutter is electronically controlled. This means that the second curtain is held back by a small solenoid. The shutter is driven by spring power, just like with any other film M.

 

The curtains are mechanically stopped, also in the classical M manner. No need to use either magnets, smoke or mirrors ...

[...]

 

Thank you for the correction. I am not sure where I got the misinformation. FWIW, there is no longer that little tick-tick sound at low speeds. Not that I really miss it.

[lars_bergquist]

Thank you for the correction. I am not sure where I got the misinformation. FWIW, there is no longer that little tick-tick sound at low speeds. Not that I really miss it.

 

Exactly. With an even halfways modern focal plane shutter, the curtains always move at the same speed. It is the delay of the second curtain alone that determines the shutter "speed", i.e. the exposure duration (time between the passage of the rear edge of the first curtain and that of the front edge of the second one). The first curtain of a mechanically governed shutter trips the second shutter. With a classical M shutter, the first shutter comes to a stop after about 1/50th of a second. If you set a slower speed than that, the timing and tripping of the second shutter has to be taken over by an escapement type (i.e. clockwork) delay mechanism, and this is the tick-tick you hear.

 

With the old screw thread Leicas, this delay mechanism was set by way of a separate slow speed dial on the front of the camera. With the M3--M6 and MP cameras, this is integrated with the general regulating mechanism under the top cover, so that all speeds are set by one single dial. In the M7, the delay mechanism is absent, instead all speeds are normally timed electronically. The two mechanical emergency speeds, 1/60 and 1/125, are within the 'fast speed range' and do not need the clockwork.

 

The old man from the Clockwork Age

[Bo_Lorentzen]

What is it with you guys, Everybody know a leica should not be stored... just use the damn thing.

 

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