Citation Hunt

The Wikipedia snippet below is not backed by a reliable source. Can you find one?

Click I got this! to go to Wikipedia and fix the snippet, or Next! to see another one. Good luck!

"

The 135 mm Hexanon for the F had a manual aperture, but the other lenses featured what was referred to as "fully automatic" aperture in the 1960s. This is not as automated as apertures eventually became. At that time it meant the aperture diaphragm was held fully open during focusing, to make for a brighter viewfinder and render a shallow depth of field, both of which helped with focusing. Once the shutter release button was pressed, the aperture was allowed to snap down to the pre-selected setting, before the shutter opened to expose the film. Further, the aperture re-opened automatically after the shutter closed. All this happened in the instant the exposure was made, while the reflex mirror was also cycling up out of the way, then back down to the viewing position.