[bottlebug]

Hi this is my first post on Pentax Forums so nice to meet you all!

I recently picked up a Pentax ME Super which came with a SMC-M 50mm 1.7 lens.

When I take off the lens and change the aperture I can clearly see the blades move. But when I mount it on the camera the aperture blades go wide open and even when I change from f/1.7 to f/22 it's still wide open all the way. The lever for making it open wide still works.
The light meter still works however when I change the aperture.

Is this a problem or is the camera designed to be like this?

Thanks for the help!

[goubejp]

The camera is designed to be like this; the blades will move only when the picture is taken, so that when you look in the viewfinder you have an image with maximum brightness. However, on the ME super, you don't have a depth of field tester that allows to close the blades to judge the depth of field.

[mattt]

Fire the camera while looking at the iris. You will see the aperture stop down to the desired setting during the process.

[Just1MoreDave]

You can demonstrate to yourself why the camera works this way. Set the lens aperture ring to f11 or so and mount it on the camera without rotating it fully, about 10 or 15 degrees short of fully mounted and locked. Now look through the viewfinder. It will be extremely dark and grainy even in bright daylight. The camera holds the blades open so it's easier to frame shots and focus, then shuts them to your chosen aperture just after you press the shutter button and before opening the shutter blades.