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06-09-2009, 08:29 AM   #16
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I am not quite sure were this rumor is coming from. I have tested the K-7 (pre-production) body with all the current DA* (SDM) lenses and they all perform exactly the same (fast and silent.) This includes the new DA* 60-250.

The camera is basically communicating to the lens how much it needs to move the focus mechanism. This is done either through the screw drive or the SDM motors. The lens involvement in determining focus is minimal (basically, letting the light pass through it).

06-09-2009, 01:08 PM   #17
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So as a side note can any one tell me how fast the 60-250 is vs the 50-135? Or similar lenses
06-09-2009, 02:11 PM   #18
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I guess it originates from here
https://www.pentaxforums.com/forums/518979-post43.html
06-09-2009, 06:07 PM   #19
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QuoteOriginally posted by JCPentax Quote
The camera is basically communicating to the lens how much it needs to move the focus mechanism. This is done either through the screw drive or the SDM motors. The lens involvement in determining focus is minimal (basically, letting the light pass through it).
The first part of your sentence said all the DA* SDM lenses are supported, but this last part says that all AF lenses are supported, since they all are screw driven.

I hope thats the case. I have an "old" PS camera, the Canon A710, and i can understand the need for quiet autofocus, as that camera's video mode would record the noise of the power drive zoom. If the reason to go to SDM lenses for the K7 was that there was less pickup of noise in the HD video. That would make sense. But it would still be neat to have that capability to USE the old AF lenses for general still photos, and where one was willing to accept the recorded noise in the HD video.

Pehaps one of the really neat things about the K7 is that it has a connection for an off-camera microphone, thus avoiding recording of all the possible on camera frame noises - when the remote mic is used. I can just see the possible complaints now on the video sound quality: "My camera records this funny noise on the video - what is it - do i need to return the camera" What a headache those posts were on the associated Canon forum. Well one can always choose what to read and what to skip :-)

thanks for the information, Phil

06-09-2009, 07:44 PM   #20
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QuoteOriginally posted by Photomy Quote
Mr. Mabo mentioned in an earlier post I saw about the need to make changes to any lenses that will use the new real time contrast detect AF sytem and only SDM line will be adaptable. Anyone care to speculate if the 60-250 which was just released was already designed to use the new contrast detect AF system? Maybe this was already answered - I could not find it.

- Tom
So, the kit lens will not be able to do the CDAF?? IF so, it is just a JOKE!
06-10-2009, 06:54 AM   #21
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QuoteOriginally posted by philbaum Quote
The first part of your sentence said all the DA* SDM lenses are supported, but this last part says that all AF lenses are supported, since they all are screw driven.
Actually what he said was that all the DA* SDM lenses perform the same: fast and silent. I'm sure the screw drive AF lenses aren't silent, but it sounds like they are supported.

I haven't heard this business about lenses having to be updated to support contrast-detect AF from anyone but Mr. Mabo. I'm not sure where he got that from, but it doesn't appear to be true.
06-10-2009, 07:10 AM   #22
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QuoteOriginally posted by RiceHigh Quote
So, the kit lens will not be able to do the CDAF?? IF so, it is just a JOKE!
Did you ever touch a K-7 prototype?
Contrast detection AF works with the kit lens (or other non-SDM lenses, and I expect it will also work with SDM lenses - didn't tested with those), however with the K-7 I've tried (early, very unfinished firmware) the AF was sloooow. As already reported (iirc) on this forum, the lens would go past the focus point, then jump back.

Maybe the lenses must be updated for fast CDAF. Maybe updating the lenses for faster AF (CD and phase-diference) would be a very good idea.
06-11-2009, 01:34 AM   #23
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Contrast AF

Just my experience from a 0.20 firmware K-7 given to me for 3 days by the Greek rep. The contrast AF works fine with all AF lenses (I tried FA50F1.4 and DA 60-250), although is quite slow. I used Contrast AF in Live View and it seems that it first scans the distance back and forth the target and then the fixes in the right position, i.e. it focuses in 3 steps.

Phase AF seems to be faster and more responsive in Continuous mode, when tested with DA60-250 (i.e. in SDM mode) but only a bit better when the FA50 was mounted. Screw driven AF had the classic hesitations and corrections before perfect focus was done.

Otherwise, as someone else pointed out already, it seems that 0.20 firmware cameras have a preliminary version of sensor/processor, so while image quality is very good at 1600 ISO, shooting pace seems to be 3.5-4 fps rather than 5.2. Handling is perfect, all buttons fit nicely. Some new features, like level indicator, are much more useful than expected.

I am waiting for a later firmware version to test my FA600F4. K20D was in pain to follow birds on flight, even large enough and results were bellow my expectations. I hope K-7 will be a big step ahead.

Cheers, Anavasi

06-11-2009, 01:37 AM   #24
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QuoteOriginally posted by Anavasi Quote
Phase AF seems to be faster and more responsive in Continuous mode, when tested with DA60-250 (i.e. in SDM mode) but only a bit better when the FA50 was mounted.
I count that as another vote for SDM faster, screw about same.
frank said in another thread that it was the opposite. Either its very lens dependent, or very different in firmware 0.2 and 0.35
06-19-2009, 10:35 AM   #25
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Any comments on whether PDAF or CDAF is better suited for low light shooting ? AF speed, accuracy and ability to lock on etc..
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