screwdrive
Posted 11/11/2010 - 16:17
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petrochemist wrote:
Tim, SDM is apparently to continue for the top of the range DA* range whilst DC is for the cheaper DA range. This implies SDM is not seen as a failure, but the better technology.
If the DC is like speculated a brush-less DC motor than SDM would have more torque, that's probably one of the reasons they use the SDM in the DA* lenses because the larger aperture need bigger elements so more weight to move around when focusing.Tim, SDM is apparently to continue for the top of the range DA* range whilst DC is for the cheaper DA range. This implies SDM is not seen as a failure, but the better technology.
And in all honesty it was the first two SDM lenses that experience problems for the rest they all seem to work fine and if the will let go of the KAF2 mount and go to KAF3 for all SDM lenses that would make thing also simpler for them and there would be less to go wrong.
Stefan
K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ
K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ
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1001 posts
16 years
Essex
So as SDM is now perceived as "bad", Pentax had to think of a new name. Hence DC. I do not believe it is fundamentally different. If a Pentax camera can drive a SDM lens, it can drive a DC lens (or even a Sigma HSM lens)
Mike
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Pentax:K5ii, K7, K100D, DA18-55, DA10-17, DA55-300, DA50-200, F100-300, F50, DA35 AL, 4* M50, 2* M135, Helicoid extension, Tak 300 f4 (& 6 film bodies)
3rd Party: Bigmos (Sigma 150-500mm OS HSM),2* 28mm, 100mm macro, 28-200 zoom, 35-80 zoom, 80-200 zoom, 80-210 zoom, 300mm M42, 600 mirror, 1000-4000 scope, 50mm M42, enlarger lenses, Sony & micro 4/3 cameras with various PK mounts, Zenit E...
Far to many tele-converters, adapters, project parts & extension tubes etc.
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