The AE finder allows you to shoot aperture priority. The Standard finder will only allow you to shoot manually. The AE finder works when you turn the shutter dial to the "A". The meter on the left will disappear and a new meter appears that shows what shutter speed the camera will be shooting at. I love the F-1n. It's built like a tank. Weighs as much as one too I've ran over a thousand rolls through the camera in the past 20 years and it still runs like a champ.