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10-11-2019, 04:58 PM   #16
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QuoteOriginally posted by midnightvisions Quote
New Question; For My K1 ii, Can anybody tell me what the differences are between the SDM motor speed / noise In the 15-30 and 24-70 lenses vs the DC in the 70-200? I prefer the SDM and PLM motors for their quietness and speed over the grinding of gears in other focus systems.
From the in depth review on pentaxforums: "DC" means that the lens uses a direct current, in-lens motor drive for the AF system. DC is faster and more reliable than the older SDM and is much better suited for live view operation. DC also supports continuous video autofocus on compatible bodies.

10-12-2019, 11:49 AM   #17
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QuoteOriginally posted by othar Quote
In other words it is also a quiet AF-system
Yes - near silent, in fact
10-12-2019, 12:02 PM   #18
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QuoteOriginally posted by midnightvisions Quote
. . . New Question; For My K1 ii, Can anybody tell me what the differences are between the SDM motor speed / noise In the 15-30 and 24-70 lenses vs the DC in the 70-200? I prefer the SDM and PLM motors for their quietness and speed over the grinding of gears in other focus systems.
it might help to look at this

QuoteQuote:
Pentax K-Mount Lens Series Explained: The differences between various Pentax lens series

. . . DA* Lenses: The DA series includes a number of "star" lenses (DA*) with top notch optical and mechanical engineering. All DA* lenses have the Quick Shift focusing system and - despite not having the WR designation - are also weather sealed.

DC, PLM or SDM: Lenses with the DC, PLM or SDM designation feature a built-in autofocus motor. Newer cameras (K100D Super, K10D, and later) will take advantage of this motor and not use the screw-drive mechanism.

Some DA lenses are DC/SDM-Only (KAF3 mount), such as the smc PENTAX-DA* 55mm F1.4 SDM prime lens and smc PENTAX-DA 17-70mm F4 zoom lens. These lenses lack the traditional screw drive autofocus coupler and will therefore only autofocus on the K10D, K100D Super, and newer Pentax cameras. . . .
Pentax K-Mount Lenses Explained: The differences between various Pentax lens series
10-14-2019, 06:12 PM   #19
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The problem I am having with the DC advertising is I have a K70 with the 55-300mm 1: 4.5-6.3 PLM and a 18-135 1: 3.5-6.3 DC lenses.
The 55-300 beats the 18-135 in focusing speed and quietness.
The DC system still has the gear noise, whereas the PLM has no noise at all.

In comparison my K1 with the 15-30mm and 24-70mm SDM lenses autofocus is compatible in speed, but are still quieter than the 18-135mm on my K70.

So from my limited experience, (and not including the video capabilities), the DC is not as good as the PLM.

Am I missing something, or just being too damn picky?

10-14-2019, 11:49 PM   #20
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The PLM is the best one but it needs small focusing groups, so I don't think we'll see it in a FF lens soon. Certainly not on the 24-70 or similar large-aperture monsters.

About DC vs SDM I would guess the ring-type SDM would be better than the DC one but I don't have any SDM-equipped lens to compare.
10-15-2019, 12:03 AM   #21
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QuoteOriginally posted by midnightvisions Quote
The problem I am having with the DC advertising is I have a K70 with the 55-300mm 1: 4.5-6.3 PLM and a 18-135 1: 3.5-6.3 DC lenses.
The 55-300 beats the 18-135 in focusing speed and quietness.
The DC system still has the gear noise, whereas the PLM has no noise at all.

In comparison my K1 with the 15-30mm and 24-70mm SDM lenses autofocus is compatible in speed, but are still quieter than the 18-135mm on my K70.

So from my limited experience, (and not including the video capabilities), the DC is not as good as the PLM.

Am I missing something, or just being too damn picky?
I only have screwdrive AF lenses, so I can only repeat what I have read and not speak from experience. But I think the 55-300mm PLM lens is focused by wire when manually focused, so there are much fewer parts to move than in your 18-135mm lens which provides a mechanical connection between optical elements and focus ring.
10-15-2019, 02:28 AM   #22
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This is a pretty good and comprehensive review: Pentax HD PENTAX-D FA* 70-200mm f/2.8 ED DC AW Review | ePHOTOzine
10-23-2019, 07:58 AM   #23
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QuoteOriginally posted by othar Quote
But I think the 55-300mm PLM lens is focused by wire when manually focused, so there are much fewer parts to move than in your 18-135mm lens which provides a mechanical connection between optical elements and focus ring.
I was under the impression that the 18-135 is using some kind of "focus-by-wire" as well since there are no "hard" stops at both ends of the zoom range (though the friction increases noticeably; can the lens be damaged when the focus ring is turned too far in one direction?), but the focussing group does seem to move when turning the ring with the lens off the camera. How does Quickshift / the focussing ring not turning when af is engaged play into this?

10-23-2019, 08:06 AM   #24
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QuoteOriginally posted by ehrwien Quote
but the focussing group does seem to move when turning the ring with the lens off the camera.
This wouldn't be possible if there wasn't a mechanical connection. As for your other questions, my most modern AF lens is the 18-55mm kit lens so I am not the most knowledgeable technical contact person
10-24-2019, 06:33 AM   #25
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Hello,

I'm also looking for some feedback on this lens. I was hoping for much lighter 70-200 F4, but it seems it's not going to show up anytime soon. I'm going on a trip to Iceland in a few months, and would like something to complement my UWA and a standard primes for K-1.

I'm familiar with in depth reviews from ephotozine (both of them) and made by folks here, but I'm not really concerned about MTFs and levels of CA; I'm mostly interested in quality of sealing (there's a lot of rain in Iceland during spring) and general reliability over long term use in far from ideal weather conditions. Plus accuracy and speed of AF (I'm not a birder, but I don't shoot only static subjects). I had DC motor in crop sensor 16-85 and had no complaints, but I dunno if it's the same thing as in 70-200 2.8.

I'm also interested in an approximate rate of lenses reported with decentering. How many folks from here had such a problem with 70-200 2.8?
10-24-2019, 12:36 PM - 1 Like   #26
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QuoteOriginally posted by BarneyL Quote
I'm familiar with in depth reviews from ephotozine (both of them) and made by folks here, but I'm not really concerned about MTFs and levels of CA; I'm mostly interested in quality of sealing (there's a lot of rain in Iceland during spring) and general reliability over long term use in far from ideal weather conditions. Plus accuracy and speed of AF (I'm not a birder, but I don't shoot only static subjects). I had DC motor in crop sensor 16-85 and had no complaints, but I dunno if it's the same thing as in 70-200 2.8.

I'm also interested in an approximate rate of lenses reported with decentering. How many folks from here had such a problem with 70-200 2.8?
The DC motor in the DFA* 70-200 is just fine from my point of view. My subjective impression is that the focusing speed is similar to the DA 16-85. It's a much heavier lens, so I guess the motor is actually more powerful to cope.

The weather resistance is also the superior AW (All Weather) type, rather than WR. It can achieve this because zooming is internal; the lens does not move in and out when zooming, thereby drawing in air.

Mine is optically perfect stunning. No issues there.

My guess is that some users may swap to the f/4 version when it eventually appears, as the size and weight is a bit of an issue. Personally, I would have a hard time giving it up.
10-25-2019, 01:12 PM - 1 Like   #27
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The DFA* 70-200 2.8 is among the finest overall lenses Pentax has produced to date. The only negative I have found is the weight. Picture quality, focus speed and accuracy are outstanding.
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