At 22:20 +0000 9/12/02, Charles Dias wrote: > I need to know urgently the differences between Nikon F4 and F4s >... I guess itīs just the motordrive ... MB20 in the first and MB23 >in the second ... If I buy a F4 and when I have money I buy a MB23 >can I replace the original MB20 to have a F4s??? ........I have an F4s I've been happy with for over 10 years until I recently got an F5........still think the F4 is a great camera........anyway, I have an original Nikon catalogue from 1992 describing the attributes of the F4........you are correct in that the F4 has the MB20 battery pack which holds 4 AA type batteries.......the F4s has the MB21 battery pack which holds 6 AA type batteries and which also gives you an additional, lockable shutter release button at the base of the grip which is very handy for shooting verticals and in addition to that, a remote terminal.........the MB23 pack is a more versatile unit that can run off of the MN20 NiCd battery unit and is consequently more expensive.........all of these battery packs are interchangeable........ Hope this helps....... Jim Baja Oregon