Help with Nikon apperture allowance

[Helen B]

'Pre-set' lenses were common before auto-aperture, and for interchangeable-mount lenses. There are two aperture rings - one, with detents, sets the limit and hence the working aperture and the other, free-floating, operates the iris. Interchangeable-mount lenses that use T-mounts are often pre-set. Here is a pre-set shift lens. You can see the setting ring (set to f/16), and above it the lever that moves the blades into the set position:

Best,
Helen

 

[epp_b]

Hold your lens up so that you see this:

Set it to the minimum aperture and, with your finger, move the little prong on the right up and down. Watch the aperture blades through glass move in relation to you moving the prong. This is how the camera controls the aperture.

Now set your aperture to it's largest opening and you can't move the prong.

Get it now?

 

[Helen B]

Thanks for showing the picture. That's what I was trying to describe back in post #10: "Look at the back of the lens. There's a little lever. Play with it - it opens and closes the iris. Now move the aperture ring..."

Best,
Helen

 

[stsinner]

Hold your lens up so that you see this:

Set it to the minimum aperture and, with your finger, move the little prong on the right up and down. Watch the aperture blades through glass move in relation to you moving the prong. This is how the camera controls the aperture.

Now set your aperture to it's largest opening and you can't move the prong.

Get it now?

I get it, I get it! Helen brought me to the realization that the ring sets the limit, and your camera adjusts the aperture every time the shutter release is pressed. I had no idea the camera body had the ability, in addition to the focus motor, to flip that lever around the close the aperture. I just never paid attention. I thought that it controlled the aperture electronically by dumbing down the sensor, not physically by manipulating the aperture blades. I thought that whatever you set that ring at was your aperture and when my camera wouldn't operate with the right at anything by 22 on a 50 1.8, I thought I was losing the fastness of the lens. I didn't see that the aperture was being held open as soon as it was mounted to the body.
I have a very good grasp of the concept now. Thank you.