07-05-2010, 02:20 PM
Dear fellow zoners,
Owning a few OM mount lenses that I use every now and then on an adapter, it came to my mind that the aperture lever spring might get worn out if the lens stays on the adapter constantly.
I suppose you know what I mean but in case of...
OM cameras, just like many other, meter with the lens wide open and it is at exposure time that the aperture lever is pushed by the camera body. The aperture is then closed -or left wide open- according to the lens aperture ring.
Now, when you mount these lenses on an adapter to use on another camera, or even a macro extension tube from the same camera maker, this lever is locked in stopped down position by a little tooth on the adapter. This is necessary as other cameras don't have any mechanical means to operate this aperture lever. In effect, it means that the aperture lever spring is compressed permanently on an adapter.
I have absolutely no knowledge of spring mechanics but my impression is that a spring held compressed permanently will lose its strength over time. Or have spring mechanics been mastered so well for ages that no one should ever worry about it <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/wink.gif' class='bbc_emoticon' alt='
' />?
Since then, I've been carefully leaving my lenses unmounted. I suppose it's the best.
Greetings,
S.
Owning a few OM mount lenses that I use every now and then on an adapter, it came to my mind that the aperture lever spring might get worn out if the lens stays on the adapter constantly.
I suppose you know what I mean but in case of...
OM cameras, just like many other, meter with the lens wide open and it is at exposure time that the aperture lever is pushed by the camera body. The aperture is then closed -or left wide open- according to the lens aperture ring.
Now, when you mount these lenses on an adapter to use on another camera, or even a macro extension tube from the same camera maker, this lever is locked in stopped down position by a little tooth on the adapter. This is necessary as other cameras don't have any mechanical means to operate this aperture lever. In effect, it means that the aperture lever spring is compressed permanently on an adapter.
I have absolutely no knowledge of spring mechanics but my impression is that a spring held compressed permanently will lose its strength over time. Or have spring mechanics been mastered so well for ages that no one should ever worry about it <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/wink.gif' class='bbc_emoticon' alt='
' />?Since then, I've been carefully leaving my lenses unmounted. I suppose it's the best.
Greetings,
S.