In article <312DC11E.478C@alpha.acast.nova.edu>, lou@alpha.acast.nova.edu says...

>I have 2 SB-15s an FG and a N2020. What is the difference between the >SB-15 an the SB-2Xs. Do I gain anything if I trade one in for a SB-2X
>for use on the N2020 or is the difference so minor that I should just
>keep one a a spare (its a great flash).

The SB-24, 25, 26's have a bit more power (especially when zoomed to 85mm), the recycle times are faster, and the color is better (you
can use a cp05Y [slight yellow] filter with the SB-15), but they
are bulkier and much more expensive, so I wouldn't trade, unless
you need the small additional power - the SB-15 (and 17 for the F3)
are gems, and are being essentually duplicated [with additional
features] by the new SB-27.
Hope This Helps