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02-12-2015, 04:13 AM   #106
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QuoteOriginally posted by formercanuck Quote
I don't think Pentax/Ricoh will get rid of the screw drive on the K mount for almost all of its gear for quite some time.

I do think that its possible that Pentax/Ricoh 'may' make an entry level or mirrorless that comes w/o the screwdrive though, and is highly discounted.
Do I think it will be soon, hell no.
Do I think it will occur in a few years... very possible.
Do I think that main stream APS-C and soon FF will still have screw drive - you bet.

Anyone remember K-500 and K-x not having focus indicators on the screen or WR.
If the primes / ltd primes ever come out with a DC motor or SDM motor, you can almost be assured that a base mirrorless / APS-C will come w/o a screwdrive as a cheaper option.
You are probably right. I sort of doubt that it is high on Pentax's list of things to do, though, to make DA limited primes with in lens focus motors. Their cheapest primes (the DA 50 f1.8 and DA 35 f2.4) are screw driven, which should say something about the current future of the in body focus motor.

02-12-2015, 12:30 PM   #107
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Until they invest in updating the plastic fantastic and the limiteds... I don't expect any to the status quo for any mainstream body with respect to the screwdrive.
02-12-2015, 12:35 PM   #108
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The fact that the full-frame model they displayed to the world at CP+ had a FA 31 mounted should end any speculation that the camera will not have an in-built focus motor.

/thread
02-12-2015, 12:53 PM   #109
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QuoteOriginally posted by rawr Quote
The fact that the full-frame model they displayed to the world at CP+ had a FA 31 mounted should end any speculation that the camera will not have an in-built focus motor.

/thread
Possibly, although they have made mistakes before (hiring non-photographers to design camera bodies for instance). I'd rather wait for an actual statement of specs before closing this particular question.

02-13-2015, 01:22 PM   #110
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I would see no reason to remove the in body motor for mainstream cameras until sometime after Pentax/Ricoh sells ONLY non screw drive lenses. Ricoh's most expensive lenses (with exception of the newest and DA* zooms) are still screw mount (eg 31mm LTD at +$1000 USD, 77mm LTD at ~$950 USD). Similarly... do you think they'd ever get the 40mm pancake lens with a DC. I don't think they'd get a motor small enough. It may be years before it happens on maintstream SLR. It could be less for a bargain entry camera, or small/mirrorless
02-13-2015, 02:45 PM   #111
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QuoteOriginally posted by formercanuck Quote
Similarly... do you think they'd ever get the 40mm pancake lens with a DC. I don't think they'd get a motor small enough.
Canon put a stepper motor in their equivalent.
And Pentax does the same with the Q 08 wide zoom.
02-13-2015, 04:20 PM   #112
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Hmm.. Canon = 22.8mm thick, Pentax xs = 9mm. Even its DA and M are still smaller than Canons 40mm


02-17-2015, 04:01 AM   #113
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QuoteOriginally posted by lytrytyr Quote
Canon put a stepper motor in their equivalent.
And Pentax does the same with the Q 08 wide zoom.
And don't forget fuji. That 27 may have very different optical constraints, but the lens is still very small, and it does have a motor inside it, as well as an electronic aperture actuator.

03-05-2015, 08:04 AM   #114
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As for screw-drive autofocus and backlash, there's calibration data in the lens' EEPROM that tells the camera what the backlash is at various distances. See Pentax's US Patent 7,822,339. While that's not the exact format of the data in the lenses, it surely gives the high-level design.
03-06-2015, 10:27 PM   #115
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The biggest issue with using screwdrive - is the basic ability to 'tune' a lens / motor combination, as the cameras body motor works at one speed.
Basically meaning lenses with long focus throws can be slower to focus (at least across the range) than one with a short throw, but it may not have as fine steps.
In this case... the 35mm LTD is also a macro, which makes the gearing / throw longer.

Eg. Pentax HD DA 35mm f/2.8 LTD vs. plastic fantastic SMC DA 35mm f/2.4 L

vs.

I personally have no issues with screwdrive, and like it - its pretty much bulletproof.
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