The F4s is unnecessarily heavy bu it does look really cool. Wasn’t it the creation of some famous Italian designer? The MB20 just makes it usable for everyday carry.
For those among you who think that the MB-20 is the way to go, here is a comparison between the F4 with MB-21 and MB-23 and an F2 with MD-2 and MB-2. The F4 IS heavier, but both are about the same in size as a sorta comparable F2. Now add the DS auto exposure to the F2 and the comparison becomes moot. The second photo shows the much smaller and lighter D600 with the two bigger, heavier cameras.