Originally posted by Wheatfield There should be two aperture rings. One is used to "preset" the aperture, the other one is used to actually stop the lens down to that aperture.
In use, you would set the aperture ring to the shooting aperture (lets say f/8), which, with old viewfinders, could make for a very dim focusing screen.
So, you would open the lens up with the second ring, focus and then turn it until it stops, which would put you at the preset aperture for shooting.
It was a way of allowing for fast aperture setting without having to count clicks.
Ah, I see what you mean. For this particular CZJ lens there is only one aperture ring. However, to 'preset' the aperture all I have to do is press the aperture ring towards the mount then turn to the desired aperture then it locks the aperture.
Is this a mark of premium lens or it makes no differnce?