On Oct 21, 2005, at 4:12 AM, Toralf Lund wrote:
Urgh. I'd say the Pentax way is better. If and when they release an
FF body, you'll probably still be able to use the DA lenses on it
to produce (at least) the 6MP APS-C sized images the lenses were
designed for.
It's a trade off. Canon's way means that they can make changes to the
mirror mechanism knowing the physical clearances of any lens that
will mount on a given body. Pentax way gives users the option of
accepting a less than perfect capture.
BTW: the Pentax DA14 will cover a 24x24mm format, max.
I'm not 100% sure I'm looking at this the right way, but I think
that means it's able to cover up to approximately 18.5x28mm in the
2:3 format. That's more or less equivalent to a 1.3 crop!
I've been wondering, could the fact that the DA lenses do seem to
have a somewhat larger circle than what's strictly required by the
APS-C sized sensor, actually be a result of a conscious design
decision, i.e. might Pentax have left some room for a possible
development towards larger sensors?
I suspect the primary reason is that they inset the 16x24 format to
ensure good corner/edge resolution with minimum light fall off. Go to
24x24, or 18.5x28, and I suspect that corner/edge performance will
suffer somewhat as you're much closer to the physical vignetting limit.
35mm camera lenses generally cover a slightly larger area with
similar insetting of the format, for similar reasons.
Godfrey
