Asahi Pentax
How do you know if the opening is effective?
Its an Asahi Pentax K1000 when I change the f-stop meter removal, but when I look through the lens, I do not see the opening of the size or smaller!
This is one of the advantages such a device. The opening is held in abeyance until you take the shot … then stop the lens down, the mirror moves out track and the shutter opens for the predetermined time. If you need to see what depth of field is to stop some f /, then use the button depth of field preview on the camera, usually on the front of the camera beside the lens.