yah..means at the tele end the max it can open is f5.6
for digicam..they are all made in a way such that they can stay at
a constant aperture (of f2.
throughout all focal
lengths or they go down by 1/3 or 1/2 a stop to f3.2 or f3.5 at the
tele end..
its a all-in-one package. lets say..for a digicam, if at 10x zoom,
the widest it can go is f5.6..and you can't increase ISO to above
200 for noise/grain will be very obvious, then chances are your
shots will be blurred (handheld).
cos even if its very sunny, at ISO of 100 and aperture f5.6, to get
a shutter of 1/400 and faster to "stabilize" your shot at 10x zoom
is quite difficult..
and then..there are lenses with constant aperture of f2.8
throughout the whole range of focal lengths for SLR too..but they
will be very very costly lor..for example, even a third party
70-200 f2.8 will cost >$1000
