Steven asks:
which one is the higher speed version of velvia 50? i am a velvia fans
and ran out the last roll of 50, so, which one should i buy, 100 or
100F? does it identical to 50 in most aspects except speed?

Velvia 100F is almost universally loathed, and I would bet $20
will be discontinued by 2009.

Toni Nikkanen wrote:
Velvia 100 is the intended replacement for 50 - though as others already
said, 50 may be coming back.

Fuji says they intend to bring Velvia II 50, and also Provia 400X,
to US markets by March, which I would interpret as June or later.