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11-10-2017, 02:03 PM   #1
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Question: is the KP AF in s-af mode better than the K3"s?

Perhaps there are people here that have experience with both cameras.
I currently have the K3 and the DA560. My biggest issue with this combo, is the often hesitant AF behavior in S-AF mode.
What I would like, is for this combo to lock on to its subject in medium to good light, and not hesitate. A bird will not sit for long, and I have missed shots because of the K3 AF not immediately locking on, but needing some pampering and delicate and careful half-pressing the shutter before reaching proper focus in many scenarios, except the brightest and most contrasty.
I am not looking for state of te art C-AF, the DA560 is too slow in that regard, but I would not know why it could not have more positive and faster accurate S-AF, not fast in absolute sense, but fast in the sense of simply locking on, without the small corrections and the need of pampering the shutter button.

Does the KP provide this? I could imagine that it does, even though the AF module is physically the same as in the K3, since it has a newer (better?) processor. The K3 processor is a bit suspect to me anyway, since I also have experienced the lock-ups and mirror flapping. Also, the KP has newer algorithms.
I will buy it if it does, because it is the single thing keeping me from really enjoying the DA560.

Chris

11-10-2017, 02:13 PM   #2
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The KP has the same AF algorithms as the K-3 II, which have been optimized compared to the K-3 for scenarios where the subject is moving closer or farther away from the camera in AF.C mode.

There was a detailed test performed here:
Pentax KP Review - Focusing | PentaxForums.com Reviews

If this is the type of shooting you do, then you'll notice an improvement. As for the single-focus speed, there shouldn't be any difference. In your case, it's likely that there simply isn't enough light for the focusing performance to reach its maximum potential. You may have to play with pre-focusing, the limiter, etc. to get better results.

However, the KP is a nice upgrade in terms of image quality, and it would allow you to shoot at a slightly higher ISO, which could allow you to gain more DoF.

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11-10-2017, 02:31 PM   #3
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Impressive difference ... in one "dimension" only.

However, this test ("AF Tracking Test") was done whith the subject moving perpendicular to the camera, so the tester did "panning".
It doesn't show much in terms of tracking other than in that dimension.
Granted, the KP might show better performance that way, but does it "track" any better than the K3/k3II when the subject is moving toward/away from the camera?
11-10-2017, 03:17 PM   #4
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QuoteOriginally posted by Adam Quote
The KP has the same AF algorithms as the K-3 II, which have been optimized compared to the K-3 for scenarios where the subject is moving closer or farther away from the camera in AF.C mode.

There was a detailed test performed here:
Pentax KP Review - Focusing | PentaxForums.com Reviews

If this is the type of shooting you do, then you'll notice an improvement. As for the single-focus speed, there shouldn't be any difference. In your case, it's likely that there simply isn't enough light for the focusing performance to reach its maximum potential. You may have to play with pre-focusing, the limiter, etc. to get better results.
The thing is, I am speaking of situations where there s or shuld be enough light to enable proper and secure focussing. It may be that the contrast then is not as high as desired, but the needless hunting and misses should not occur. In fact, I do sometimes get very good results on the same shoot in half the light and contrast. The AF behavior of the K3 is overall good, but not reliable and sometimes "predictably" unreliable, if you know what I mean. I'm getting at a point where, if this is as good as single point phase detection AF in a Dslr gets, then I am willing to sell all and switch to mirrorless with on chip phase detection AF. I am hoping that a better processor will in the field get me better and more reliable AF. Perhaps the best way to describe it, is by saying that I feel like I continually have to "wake the K3 up", spur it on to get on with AF and get ir right, like a slow computer you want to get the h**l on with it. I don't see the in lens DA560 DC motor as the bottleneck here, but perhaps it is also playing a role in the endless corrections and back and forth zipping. Anyway, I am getting to a point where I either want a better Pentax Dslr, or search for alternatives....

Now, I know that the only way to know whether the KP does a better job, is to get one, but I would like to know more or less whether it at least has a chance of being so. My hope is in the new housing, the new processor and revised programming....

Chris

---------- Post added 11-10-17 at 11:21 PM ----------

QuoteOriginally posted by jpzk Quote
Impressive difference ... in one "dimension" only.

However, this test ("AF Tracking Test") was done whith the subject moving perpendicular to the camera, so the tester did "panning".
It doesn't show much in terms of tracking other than in that dimension.
Granted, the KP might show better performance that way, but does it "track" any better than the K3/k3II when the subject is moving toward/away from the camera?
No, it is not about tracking at all for me, just and only about focus lock-on in S-AF and reliability and responsiveness on the moment that I ned it to focus.

Chris


Last edited by Chris Mak; 11-10-2017 at 03:23 PM.
11-10-2017, 04:26 PM   #5
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Given that the K-3II successor is probably still some months away and will be very expensive, the KP might be your better solution rather than the K-3 which been a source of much vexation...

QuoteOriginally posted by Chris Mak Quote
The K3 is a nice camera, but it's not a camera that I will keep for longer than neccessary. There are just too many things that could be better for my use (with the DA560): AF point increase, more consistent AF (even in S-AF I get misses, and it generally is too much prone to focus hesitating). IQ could have a bit more "bite", the K3 is just a bit too soft in its rendering (I liked the K5IIs better). Better high iso and a bit more DR. And for sure, n mirror flapping, that is just about the most awfull camera behavior I have come across. A tilting back LCD. Better inbody SR (already available with the 5-axis SR of the KP).

There are just too many reasons to upgrade to grow old with the K3....
Looking at your list, you may want to see if rental might be a possibility before purchase.
  • No AF point increase
  • AF might be better than the K-3, though it is hard to say for your particular use case. I suspect that Adam's comment is spot on.
  • Extracting more "bite" from the KP is unlikely if you are shooting RAW below ISO 3200
  • Battery life might become an issue
  • Some features are missing, less capable, or less accessible than on the K-3
OTOH, prices are not bad at present and the KP might possibly be a step up. Perhaps @monochrome will chime in. He is a current KP owner and has extensive K-3 experience.


Steve
11-10-2017, 05:27 PM   #6
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Chris - one observation about the K-3 rendering too softly compared to the K-5IIs...

Bear in mind that the K-3 and KP have a not-insignificant resolution advantage over the K-5IIs, and are more demanding of lens performance as a result (if critical sharpness at 100% reproduction is your benchmark).

I use many camera bodies - from the early *ist DL to the K-3II, and none has a problem with sharpness of image capture (assuming RAW shooting with typical post-processing)...

Last edited by BigMackCam; 11-11-2017 at 12:52 AM.
11-10-2017, 06:21 PM   #7
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QuoteOriginally posted by Chris Mak Quote
The thing is, I am speaking of situations where there s or shuld be enough light to enable proper and secure focussing. It may be that the contrast then is not as high as desired, but the needless hunting and misses should not occur. In fact, I do sometimes get very good results on the same shoot in half the light and contrast. The AF behavior of the K3 is overall good, but not reliable and sometimes "predictably" unreliable, if you know what I mean. I'm getting at a point where, if this is as good as single point phase detection AF in a Dslr gets, then I am willing to sell all and switch to mirrorless with on chip phase detection AF. I am hoping that a better processor will in the field get me better and more reliable AF. Perhaps the best way to describe it, is by saying that I feel like I continually have to "wake the K3 up", spur it on to get on with AF and get ir right, like a slow computer you want to get the h**l on with it. I don't see the in lens DA560 DC motor as the bottleneck here, but perhaps it is also playing a role in the endless corrections and back and forth zipping. Anyway, I am getting to a point where I either want a better Pentax Dslr, or search for alternatives....
The only thing that would really make a big difference would be a faster-focusing lens. You yourself admitted that the lens is pretty slow in that regard

The DA 55-300mm PLM plus the 1.4x teleconverter may be worth trying. That lens focuses as fast as the best that the competition has to offer (almost instantly, you can't even measure it).

Adam
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11-10-2017, 07:19 PM - 1 Like   #8
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QuoteOriginally posted by BigMackCam Quote
and are more demanding of lens performance as a result
More demanding of photographer performance as well.


Steve

(...remembering well the humbling experience of being a new K-3 owner...)

11-10-2017, 11:26 PM   #9
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If you haven't given back-button focusing a try yet, it might be worth looking into. By moving AF activation to the 'AF' button on the rear of the camera, you won't be performing the delicate working of the shutter button for both AF and making the exposure.
I have all of my cameras set for back button focusing, and cannot imagine going back to trying to control two distinct functions with one button. Good Luck!
11-11-2017, 03:20 AM   #10
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QuoteOriginally posted by Adam Quote
The only thing that would really make a big difference would be a faster-focusing lens. You yourself admitted that the lens is pretty slow in that regard
Perhaps you are right. Though it is not essentially about focuussing speed, but about focussing consistency and accuracy as well as responsiveness on the side of the camera.
If I am to replace the DA560, it will be by the new Sigma 500/4 and a matching Nikon body

Chris
11-11-2017, 09:23 AM   #11
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I don’t have experience with AF (DA) extreme telephoto / long telephoto on either K-3 or KP*, but I can say on KP in AF.S (9-point or single point adjusted) my FA*300/4.5 consistently locks nearly instantaneously, even when dramatically changing distances.

FA*200/2.8 hunts forever, so in my experience the lens does matter. IMHO f/2.8 lenses are a challenge for Pentax APSc cameras, especially for K-3, but I have no proof and can’t assert my finding. IIRC the AF sensor was improved for K-3ll (KP) with more f/2.8 cross-type points and the result was a marked improvement over K-3.

I use the five DA Limiteds on KP since it is my casual camera. In most light the 35, 40 and especially HD DA70 lock and stay locked. The wider lenses are less certain. KP is more confident than I recall K-3 was, again, at portrait f/l. The person from whom I bought the KP and FA*300, @cali92rs, used the combo for birding and was pleased with the AF and images.

Hope that helps a little.

* I have a K-1 for more deliberate use, mostly with manual lenses up to 1000mm.

Last edited by monochrome; 11-11-2017 at 11:19 AM.
11-11-2017, 05:01 PM   #12
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QuoteOriginally posted by Chris Mak Quote
Perhaps there are people here that have experience with both cameras.
I currently have the K3 and the DA560. My biggest issue with this combo, is the often hesitant AF behavior in S-AF mode.
What I would like, is for this combo to lock on to its subject in medium to good light, and not hesitate. A bird will not sit for long, and I have missed shots because of the K3 AF not immediately locking on, but needing some pampering and delicate and careful half-pressing the shutter before reaching proper focus in many scenarios, except the brightest and most contrasty.
I am not looking for state of te art C-AF, the DA560 is too slow in that regard, but I would not know why it could not have more positive and faster accurate S-AF, not fast in absolute sense, but fast in the sense of simply locking on, without the small corrections and the need of pampering the shutter button.

Chris
What AF point(s) active in AF-S? I would only use the Center Point for birds in trees.

Have you tried using AF Adjust? I've had trouble with primes locking in the past due to front/back focus. Adjusting focus resolved the issue.

Last edited by audiobomber; 11-11-2017 at 06:05 PM.
11-12-2017, 01:37 AM - 1 Like   #13
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QuoteOriginally posted by monochrome Quote
IIRC the AF sensor was improved for K-3ll (KP) with more f/2.8 cross-type points and the result was a marked improvement over K-3.
It is my recollections as well that there was some sort of improvement in the AF in the K-3II over the K-3, but have been unable to find any documentation of different AF module hardware in reviews, the official specs, or Web site promotional materials.
  • All three (K-3, K-3II, and KP) have SAFOX 11 27 point with 25 cross-point.
  • AF firmware improvements were made for the K-3II for faster AF-C in general as well as AF-S with a selection lenses:
    • HD PENTAX-D FA★70-200mmF2.8ED DC AW
    • HD PENTAX-D FA 150-450mmF4.5-5.6ED DC AW
    • HD PENTAX-DA 18-50mmF4-5.6 DC WR RE
  • New AF firmware improvements are claimed for the KP
  • All three have three (3) f/2.8-tuned AF points in the center column
  • All three are spec'd with the same claimed low light (-3 EV) capability
  • The detailed review of the KP on this site indicated a substantial improvement in tracking performance over the K-3 and better overall AF than the K-3
Given that the DA 560/5.6 is not known for its AF speed, I have my doubts that the KP would provide the boost that the OP desires.


Steve
11-12-2017, 07:20 AM   #14
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Apparently I recalled only partially correctly . I havent had a K-3 in roughly 18 months -sold when I got the K-1 - and the KP was a second-hand impulse purchase.

The major variables in my use between KP and K-1 are the KP faster frame rate, and I sometimes use facial recognition tracking in LV on KP.
QuoteOriginally posted by stevebrot Quote
It is my recollections as well that there was some sort of improvement in the AF in the K-3II over the K-3, but have been unable to find any documentation of different AF module hardware in reviews, the official specs, or Web site promotional materials.
  • All three (K-3, K-3II, and KP) have SAFOX 11 27 point with 25 cross-point.
  • AF firmware improvements were made for the K-3II for faster AF-C in general as well as AF-S with a selection lenses:
    • HD PENTAX-D FA★70-200mmF2.8ED DC AW
    • HD PENTAX-D FA 150-450mmF4.5-5.6ED DC AW
    • HD PENTAX-DA 18-50mmF4-5.6 DC WR RE
  • New AF firmware improvements are claimed for the KP
  • All three have three (3) f/2.8-tuned AF points in the center column
  • All three are spec'd with the same claimed low light (-3 EV) capability
  • The detailed review of the KP on this site indicated a substantial improvement in tracking performance over the K-3 and better overall AF than the K-3
Given that the DA 560/5.6 is not known for its AF speed, I have my doubts that the KP would provide the boost that the OP desires.


Steve
11-13-2017, 03:39 AM   #15
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QuoteOriginally posted by audiobomber Quote
What AF point(s) active in AF-S? I would only use the Center Point for birds in trees.

Have you tried using AF Adjust? I've had trouble with primes locking in the past due to front/back focus. Adjusting focus resolved the issue.
I have done AF adjudtment, over a longer period of time it has settled on -2 for the DA560, and -3 for the DA560+ 1.4tc.
I normally only use centre point s-af, because I will mostly apply a certain amount of cropping afterwards anyway.
I don't actually have a problem getting either the DA560 or the combo with tc1.4 to lock focus, especially the combo has better AF than I initially expected. The problem is the lack of reliable consistency and the lack of a certain amount of discrimination of the precise subject you want to lock onto. I cannot really see the lens or the lens motor as the cause of this, but perhaps I am wrong.
Sometimes I am hiking, lift the camera and want to focus, and what I am looking for, is a camera that will simply start AF immediately and lock, period. What I get with the K3/DA560, is that I half press the shutter button, and often it initially just stutters a bit, and goes back and forth some, or even needs multiple half presses before even starting the focus travel, and I typically need several attempts before I get it to focus on the bird, even when it is a clearly isolated subject.
I don't so much care about actual speed in ms. but I am getting to a point where I am not enjoying shooting the Pentax setup any longer, because birds don't give you time to fiddle with your auto focus. I am only interested in a future Pentax camera that reacts immediately when I lift the camera and half press the shutter button, singles out the subject, also smaller subjects, and locks focus accurately, and decisively. If the KP can give me that, I am in, or the possible K3 successor. If it on the other hand also resorts to stuttering, need of pampering, searching for the subject while you have the active AF point exactly on it, then it is time for me to switch to the new Sigma 500/4 and Nikon D500/7200.
I would rather stay with the Pentax though, obviously because of cost, but also because it otherwise fits my needs. It is a bit of a grey area, because I could see better AF programming and especially a better, more reliable processor giving me what I need. The K3 processor is suspect in my book anyway, having had the mirror flapping and locking up on several occasions.

Chris

---------- Post added 11-13-17 at 11:49 AM ----------

QuoteOriginally posted by stevebrot Quote
It is my recollections as well that there was some sort of improvement in the AF in the K-3II over the K-3, but have been unable to find any documentation of different AF module hardware in reviews, the official specs, or Web site promotional materials.
  • All three (K-3, K-3II, and KP) have SAFOX 11 27 point with 25 cross-point.
  • AF firmware improvements were made for the K-3II for faster AF-C in general as well as AF-S with a selection lenses:
    • HD PENTAX-D FA★70-200mmF2.8ED DC AW
    • HD PENTAX-D FA 150-450mmF4.5-5.6ED DC AW
    • HD PENTAX-DA 18-50mmF4-5.6 DC WR RE
  • New AF firmware improvements are claimed for the KP
  • All three have three (3) f/2.8-tuned AF points in the center column
  • All three are spec'd with the same claimed low light (-3 EV) capability
  • The detailed review of the KP on this site indicated a substantial improvement in tracking performance over the K-3 and better overall AF than the K-3
Given that the DA 560/5.6 is not known for its AF speed, I have my doubts that the KP would provide the boost that the OP desires.
See my answer to audiobomber

Chris

Last edited by Chris Mak; 11-13-2017 at 03:48 AM.
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