BMbikerider
Member
Almost all the German (and by extension European) made photographic camera systems using springs are, at their cocked position, only burdened (is this the correct expression?) for +/- 80% of their capacity, and can be safely stored cocked (and some should be so).
This goes for Leitz-, Zeiss Ikon-, Voigtländer-, Linhof-, Hasselblad-, Compur- and Prontor- shutter systems, and alike.
Regardless it be focal- or central shutters.
And yes, running mechanical shutters regularly is good (just like your muscles).
The famous camera repairman Will van Manen told me so.
I don't know about the Japan and USA made cameras/shutters.
I am not sure if you are, meaning leaving them cocked at 80% means that they are only at 80% stressed, but if you are, that is absolutely poppycock. Any stress caused by tension on metallic springs of any description (Ignoring those fitted to vehicles) will loose their tension and weaken off over a period of time, if left cocked when not in use. Just what is the problem with ensuring the shutter is fired before packing up the days photography? at worst you only waste one frame. Consider that, against having the camera serviced to restore the accuracy, what will that cost?
In the case of Leica, and similar shutter mechanisms with horizontally travelling blinds, leaving the shutter cocked will also place a strain on the shutter blinds as well. In the words of a Leica trained engineer in Wetzlar when I paid a visit some years ago, was one of the most common problems with focal plane shutters is caused buy not relieving the tension on the shutter mechanism
Cruelty and abuse of fine and somewhat delicate mechanical machinery should be a hanging offence.