George-- >>>>>>>>>>Wait a minute! A thought just occurred to me. This is a variable aperture lens. Does that affect the entire aperture range or just the maximum aperture?<<<<<<<<<<<<< Yep, that's probably it. This actually means that the lens is functioning properly. My 28-70 does exactly the same thing. With the N90s, and the Tamron 90mm macro lens (and almost certainly the Nikon "D" macros and beyond), the camera/lens combo will even recalculate the working f-stop when the lens starts getting into macro range. Most if not all variable-aperture zooms will vary the aperture over their entire zooming length, and I know that my N90s will show the difference in f-stop in the viewfinder readout. Canon has electronic aperture control which will keep the f-stop of a variable aperture zoom constant (except wide-open, of course), and the Pentax PZ-1p has the option of setting the f-stop via the lens or the camera body, the latter of which will perform the same feat. It is helpful for studio flash work, where the flashes put out a consistent amount of light from shot to shot. A variable-aperture zoom relies on the automatics of the camera to adjust the exposure and keep it consistent, which of course it will do by increasing the exposure time or popping more power through the flash. Using a stop-action programmed mode will mitigate this to a certain extent when shooting with available light. As for the longer-sounding shutter problem, I don't know about that one. -BC-
