Nikon Coolpix 990 - Manual (Page 30)

Fixed Aperture - if possible the aperture is fixed when zooming in or out.
Those of us with the Coolpix 950 practically screamed for this option and now we have
it (at least 990 owners have it). You can have the camera remember where the lens was
when you power down and it returns there on power up. Or you can manually lock it to
full wideangle or full zoom position.