Originally posted by Snapper_UK If I set the lens at f4 and shoot at 300 does the camera overide this setting then and go to f5.6?
If the physical opening of the aperture ring gives f/4 at 70mm,
the same opening will give a smaller "f number" aperture, like f/5.6,
if you increase the focal length of the lens by zooming in.
Originally posted by Snapper_UK I understand aperture priority but I need to know how to set the lens either using A or manually and what it will do at differing lengths.
I don't think you need to worry about this at all, John.
Just set an aperture that you think is right, like f/5.6 or f/8,
then go ahead and shoot with the camera set to Auto exposure.
Unlike slide film, negative film is quite forgiving
about any minor errors of exposure.