I was out playing with my camera today checking out the effects of aperture on depth of field. I ended up with two photos with different exposures and I'm trying to understand why. The camera is a Nikon D5600 with a 18-55 mm, f/3.5-5.6 lens. Both photos were taken in auto exposure mode and metering mode = pattern. Both were also taken in aperture priority mode. For the first picture I set ISO = 100, f/4.5. The camera set the shutter speed to 1/640. For the second picture I set ISO = 800, f/22. The camera set the shutter speed to 1/200. Since the camera was in auto exposure mode I would expect the exposures to be more similar and am trying to understand why the second came out lighter.