Originally Posted by
William W
When the Camera is in A Mode it 'doesn’t matter' to ‘the exposure that the camera calculates’ – and I think that is your point . . . (however when using any zoom lens, due consideration has to be made to the fact that zooming MIGHT change how the TTL Light Meter evaluates that new scene)
BUT -
I think that having a non–varying maximum aperture zoom lens (vs. a varying maximum aperture a zoom lens) DOES matter when shooting in A Mode (Aperture Priority Mode).
I think it is especially important to outline to a novice that there is trap when using a Varying Maximum Aperture Zoom Lens and the camera in A Mode. (like the Kit Lens that the OP presently has - that lens has a Varying Maximum Aperture - the maximum aperture of the lens is F/3.5 at 18mm and F/5.6 at 55mm)
The trap is avoided by never setting the aperture at the fastest aperture that the lens has available.
My two major areas of concern are:
1. setting A Mode at the FASTEST Aperture and whilst making due and diligent consideration of the slowest shutter speed likely in any particular shooting scenario, then when zooming in the shutter speed can drop and that might result in SUBJECT MOTION BLUR.
2. (when working with Flash) setting A Mode at the FASTEST Aperture whilst making due and diligent consideration of the Flash Maximum Working Distance, then when zooming in, the Flash Working Distance may shorten considerably and that might result in UNDEREXPOSURE
WW