This also "powers" whatever it is that sets the aperture (2.8 to 22) and shutter speed (choice of either 1/40th or 1/200th sec). Consequently, there are no batteries: great! T
The aperture is set by the light value, but I'm fairly sure the shutter speed is always at 1/200 in A mode. The manual mode is designed for flash, not manual shooting. It closes the aperture more or less based on the amount of light while in the "manual" mode. Only in manual flash mode does it use the 1/40 second shutter speed IIRC.

It's a great camera. I have one in my point and shoot collection. I read somewhere that the iris shape does not effect the image itself. I believe it effects bokeh (?) and I know it effects sunstars. Other than that I don't think it's bad.