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04-11-2021, 09:32 AM   #76
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QuoteOriginally posted by reh321 Quote
We cannot focus on just the motor.
KAF4 would still be useful to those poor souls who own a K-50 / K-70 and experience "Dark Image Syndrome".
They could use a 55-300mm PLM lens, for example, even though its predecessor would be of little use to them.
...except "dark image syndrome" as it might exist on some older cameras is not in the least pertinent to this discussion.
Perhaps you could move on past for this thread.

04-11-2021, 09:41 AM - 1 Like   #77
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QuoteOriginally posted by gatorguy Quote
...except "dark image syndrome" as it might exist on some older cameras is not in the least pertinent to this discussion.
Perhaps you could move on past for this thread.
It could be pertinent for those users who use a lower-tier camera and experience the problem for themselves.
That would be a reason for not ignoring the type of mount - of focusing on the type of motor - in any discussion of lens design.
There, I have made my point - which will be relevant for any Pentax lens, since any of them could be used on a K-70,
but I won't raise that point any more on this thread if that is your desire, since you are a moderator.

Last edited by reh321; 04-11-2021 at 09:51 AM.
04-11-2021, 09:54 AM   #78
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QuoteOriginally posted by reh321 Quote
We cannot focus on just the motor.
KAF4 would still be useful to those poor souls who own a K-50 / K-70 and experience "Dark Image Syndrome".
They could use a 55-300mm PLM lens, for example, even though its predecessor would be of little use to them.
I believe he was talking about in the context of AF-C.

Edit: Never mind, I see we're moving on.
04-11-2021, 11:42 AM   #79
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QuoteOriginally posted by thibs Quote
I think we can disregard the mount itself completely.

KAF2 can mean screwdrive or old SDM, KAF3 can be old SDM but also DC
KAF4 either PLM or new SDM.

Makes little sense IMO. Let's focus (pun intended) on the type of motor.
So, what does focusing on motor-type gain for us? The primary focus of this thread is AF on the K-3iii {which will work with any lens AF technology}.
Most likely Pentax will use "PLM" only if they can make the focusing group sufficiently small, which seems to limit how "fast" the lens can be.
I believe Pentax will be more interested in final specs than in the technology used to reach those specs.


Last edited by reh321; 04-11-2021 at 11:47 AM.
04-11-2021, 12:08 PM   #80
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QuoteOriginally posted by reh321 Quote
So, what does focusing on motor-type gain for us? The primary focus of this thread is AF on the K-3iii {which will work with any lens AF technology}.
Most likely Pentax will use "PLM" only if they can make the focusing group sufficiently small, which seems to limit how "fast" the lens can be.
I believe Pentax will be more interested in final specs than in the technology used to reach those specs.
The primary focus of this thread is AF-C performance on the K-3 III. Not AF in general. For example Scewdrive and DC don't preform as well for AF-C as SDM and PLM.

At one point in the thread there was discussion about maybe the mount type effecting performance, but then after researching I concluded it isn't the direct cause of varying performance. I (and others) concluded that the motor type and lens weight are the primary factors that effect AF-C performance, not the mount type.

Last edited by Tesla; 04-11-2021 at 02:11 PM.
04-11-2021, 03:14 PM   #81
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QuoteOriginally posted by Tesla Quote
The primary focus of this thread is AF-C performance on the K-3 III. Not AF in general. For example Scewdrive and DC don't preform as well for AF-C as SDM and PLM.

At one point in the thread there was discussion about maybe the mount type effecting performance, but then after researching I concluded it isn't the direct cause of varying performance. I (and others) concluded that the motor type and lens weight are the primary factors that effect AF-C performance, not the mount type.
I don't believe enough information is available to make a conclusion about motors, but you can continue to guess about it if you want to.
04-11-2021, 03:16 PM   #82
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QuoteOriginally posted by reh321 Quote
I don't believe enough information is available to make a conclusion about motors, but you can continue to guess about it if you want to.
I wasn't guessing. I read this article:
The 5 Lens Autofocus Drive Types Explained - Articles and Tips | PentaxForums.com

04-11-2021, 03:19 PM   #83
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QuoteOriginally posted by Tesla Quote
As someone said a few posts earlier:
QuoteOriginally posted by Tesla Quote
The primary focus of this thread is AF-C performance on the K-3 III. Not AF in general.

Last edited by reh321; 04-11-2021 at 03:25 PM.
04-11-2021, 03:26 PM   #84
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QuoteOriginally posted by reh321 Quote
So your guessing was informed by reading the same article many of us read - it is still guessing once you try to reach conclusions beyond what is actually stated.
I'll call it an educated guess. The point is that performance isn't based on mount type. Please tell me how the mount type would effect AF-C.

Last edited by Tesla; 04-11-2021 at 05:24 PM.
04-11-2021, 03:28 PM   #85
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QuoteOriginally posted by Tesla Quote
If makes you happy, I'll call it an educated guess. The point is that performance isn't based on mount type. Please tell me how the mount type would effect AF-C.
As someone said a few posts earlier:
QuoteOriginally posted by Tesla Quote
The primary focus of this thread is AF-C performance on the K-3 III. Not AF in general.
I promised almost six hours ago not to talk any more here about mount type; I suggest you make the same promise vis-a-vis motor type.

Last edited by reh321; 04-11-2021 at 03:34 PM.
04-11-2021, 03:32 PM   #86
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QuoteOriginally posted by reh321 Quote
I promised almost six hours ago not to talk any more here about mount type; I suggest you make the same promise vis-a-vis motor type.
QuoteOriginally posted by gatorguy Quote
...except "dark image syndrome" as it might exist on some older cameras is not in the least pertinent to this discussion.
Perhaps you could move on past for this thread.

I don't see anything there about mount type. Mount type has been discussed throughout this thread. But anyway, I don't think we are on the same page, so yeah, I'll move on.

Last edited by Tesla; 04-12-2021 at 08:14 AM.
04-11-2021, 04:54 PM - 5 Likes   #87
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Get a room, you two.
Some wholesale deletions of posts will ensue if this bickering doesn't stop.
04-11-2021, 05:21 PM - 1 Like   #88
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@reh321 I apologize for the heated debate.


@Sandy Hancock I don't know if you noticed, but we already agreed to move on.
04-13-2021, 01:52 PM   #89
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So .... this thread started with a great title: " AF-C of K3III is impressive".

What really interests me is: how impressive will it be, using a DA*300/4, for BIF and a mix of BIF/low light conditions ?
I know it'll have to wait until the camera becomes available to more users here before we can actually see how "impressive" the AF-C will be (wishful thinking?).

Example: on a hiking tour in the deep forest/bush, you see a very small and well camouflaged Brow Creeper against the tree bark. That small bird moves quite fast while searching for foodstuff. Often times, using the K3, the numbers (camera is set for TAv) go up to ISO3200 to ISO 4000 at 1/1000s !! Of course, there is a lot of resulting grain and at the same time, the camera has a heck of a time to AF on that bird, even in AF-S.
I'm including a sample shot here.
This was shot in AF.S, BTW.

((Mod's: delete the picture if you feel that it has "no business" to be here on this thread))

04-13-2021, 07:10 PM   #90
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QuoteOriginally posted by jpzk Quote
Example: on a hiking tour in the deep forest/bush, you see a very small and well camouflaged Brow Creeper against the tree bark. That small bird moves quite fast while searching for foodstuff. Often times, using the K3, the numbers (camera is set for TAv) go up to ISO3200 to ISO 4000 at 1/1000s !! Of course, there is a lot of resulting grain and at the same time, the camera has a heck of a time to AF on that bird, even in AF-S.
I think any AF system is going to have a problem distinguishing that subject from the background due to camouflage and low contrast between the two, but should be able to focus on the tree itself. Nevertheless I'm hoping that I'll be able to use something other than centre spot AF with the K3iii. I can't wait to try it out with the DFA 150-450!
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