carstenw Posted August 4, 2015 Share #1 Â Posted August 4, 2015 Advertisement (gone after registration) I have two Leica R lenses (35/1.4, 180/2) with Nikon mounts, and now want to swap them back to the Leica R mount in preparation for a sale. I have noticed that with the 180 (I have only done this lens so far), when I turn the aperture ring, the aperture stops down immediately. The little lever on the back opens it again. Â This seems backwards to me, as I am used to the opposite from Nikon, i.e. the aperture stays open until the lever is activated. Â Can someone confirm whether this is normal, or whether I have missed a step (in which case, what might I have done wrong)? Link to post Share on other sites More sharing options...
Advertisement Posted August 4, 2015 Posted August 4, 2015 Hi carstenw, Take a look here Reverting mount swap, question on stop-down. I'm sure you'll find what you were looking for!
dpitt Posted August 4, 2015 Share #2 Â Posted August 4, 2015 Seems to be normal. Took one of my original R lenses, stop down closes diaphragm immediately and lever will open it again. Link to post Share on other sites More sharing options...
carstenw Posted August 4, 2015 Author Share #3 Â Posted August 4, 2015 It turns out that my Nikon lenses also do this, that is, the manual ones I guess I was thinking of auto-diaphragm lenses. Thanks! Link to post Share on other sites More sharing options...
gyoung Posted August 5, 2015 Share #4  Posted August 5, 2015 If I remember rightly (I haven't any such lenses to hand where I am at the moment) its Pentax that is 'normally' open and closed down by the camera, on Nikon lenses the diaphragm is normally closed and then held open by the camera until the shutter is released  Gerry Link to post Share on other sites More sharing options...
TomB_tx Posted August 5, 2015 Share #5  Posted August 5, 2015 If I remember rightly (I haven't any such lenses to hand where I am at the moment) its Pentax that is 'normally' open and closed down by the camera, on Nikon lenses the diaphragm is normally closed and then held open by the camera until the shutter is released  Gerry That was true of Pentax M42 Takumar lenses where the body pushed in a small in, stopping down the lens. That meant the body mechanism was strong enough to always close the diaphragm, and could interlock so the shutter would fire only after the lens stopped down. However, when Pentax changed to the K mount the action reversed, so that a spring in the lens closed the aperture when released by the body. This action is more likely to have sluggish diaphragm problems, like my Canon FL lenses back in the 1960s. (Which is why I traded them all towards a Leicaflex SL.) Link to post Share on other sites More sharing options...
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