On Sat, Sep 02, 2006 at 10:19:57AM -0400, K.Takeshita wrote: > Adam Maas mykroft at mykroft.com Sat Sep 2 08:49:28 EST 2006 > > >> 400/4 with SSM would be neat. Can't see any good reason to make it > >> DFA, though. DA will make it smaller, cheaper and just as good. > >> > >> > >> Jostein > >> > > > Actually, the size constraints on a 400 are all in the glass diameter > > (for a given aperture), format is essentially irrelevant to this, at > > least until you start talking LF, so there's zero reason to make it a DA > > lens since it will be the same size anyways. > > Exactly. After certain size (say 200mm or so), there is no reason to make > it a DA. > Still some hope for FF wishers :-).
I thought a significant difference between DA and DFA was the presence of an aperture ring. Sure, longer focal lengths are going to have an image circle larger than an APS-sized sensor. But that in itself isn't enough to make it a DFA lens. If, as we expect, these new lenses incorporate a new auto-focus mechanism then they are designed for use mainly on new cameras. As such, I doubt that Pentax would bother with the extra complication of an aperture ring. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
