The F and Fa lenses already report that set aperture to the camera body,
if it wishes to read it. They could be used entirely electronically as
is the new Panasonic/Leica 4/3 duo. No real complication at all, the
extra control costs pennies to implement, and Pentax keeps is promise
about keeping aperture rings on DFA lenses while still screwing film
body users. Everybody wins!
John Francis wrote:
>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.
>
>
>
>
--
Things should be made as simple as possible -- but no simpler.
--Albert Einstein
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