In the following specifications table of the new DA 17-70/F4 SDM found in the Pentax Norway website:-
http://www.pentax.no/accounts/433774/File/Datablader/Objektiver/18720.xls
It is stated that "Autofocus only functions if the mounted lens features a supersonic motor (the camera motor will not drive autofocus)."
Putting aside the logical mistake for the first part of the statement (how comes in the specs of a SDM lens to state about "if the mounted lens features a supersonic motor"?), I think what it really wants to tell is for the message in the brackets, that is, "the camera motor will not drive autofocus (with the DA 17-70 lens), which is simply meant that when the DA 17-70 is mounted on any older Pentax DSLR bodies prior to the K10D, it will have no AF function as none of those older bodies could support any SDM lenses. For AF to work, it must be used on one of the following four latest Pentax DSLR bodies: either a K10D, K100D Super, K20D or a K200D.
So, if Pentax starts to drop support for body driven AF in their latest lens, what does this imply? It simply hints that in the future it is possible to see new Pentax DSLR bodies which do not have body AF motor at all (like the Nikon D40/40X etc.) or more new Pentax AF lenses that are yet lens motor driven alone for the AF and it is also possible that eventually Pentax will completely discard their older body AF system.
No matter any or all of the above three possible cases happen later, it just means less backward and/or forward compatibility between different generations of lenses and bodies.
Nonetheless, without the burden of compatibility, that "pure" SDM design *may* have better AF performance (faster and/or more accurate, hopefully) and that another thing is for sure - it is simpler in design and is surely cheaper to make, no matter for the lens or even for the body - which only lens driven AF is included.
hrm, i haven't heard about this yet...thanks for posting though!
ReplyDeletehttp://pentaxmilitia.com/
They cannot do the same thing as Nikon did with the D40 for a simple reason, look at the Pentax catalog for SDM lenses... The only ones are DA* It would make no sense to make a entry-level body that can only drive top-of-the-line lenses!
ReplyDeleteAlso Pentax has to make as much lens compatible with SDM because all the other are doing the same. And without SDM the Pentax line will feel very old technologically speaking. I expect to see every new lens with SDM from now on (except maybe some primes).
AFAIK, Pentax will not drop the body driven AF because it simply can't do that. It's because of the Limited lineup of lenses (31mm, 77mm, 21mm, 70mm, 35mm (new without SDM!), 40mm) and some other normal primes like the 100mm f/2.8, 14mm f/2.8 etc.
ReplyDeleteSo the new body would be limited to what ... 5 or 6 lenses that don't cover the whole range and all cost around 900€? Give me a break. Pentax is not that stupid. And even if they could produce a couple of more lenses that support SDM it would be a stupid thing to do simply because they would not sell as much of the other superb lenses.
I think you should read the bottom of this page (the Q&A section):
http://www.pentaximaging.com/footer/news_media_article?ArticleId=10527486
It's simply because of cost effective engineering and weight reduction. And as stated in the FAQ section - future bodies will have the old screw motor to stay compatible with the old lenses (that's the only reasonable thing to do).
Nikon can afford to do such a stupid thing because they have a bigger lens lineup, Pentax doesn't and can't. At least for now.