[Larrymc]

This looks very good! I am starting to wonder if my camera has some problem.
I have the AF fine adjustment set to -10 for the Three lenses I use, and still it is front focused when doing portraits. Here is an example of a full body portrait and it is badly front focused, and the info of the photo. I just do not understand this inconsistent focus performance. Sometimes the focus is right on, and often it is not. The best results I am getting is when I use center spot focus.

I agree with @clackers. In AF mode you are giving the autofocus system too many options and from your rear lcd screen its clear to see that the system chose the center left of your model and not the model's face or eyes. Looks to me that the model's midriff area is most in focus right where the system says the focus was. Zone select will be your best option or AF Select.

You haven't said what technique you use to AF fine tune your lens but If I were you I'd give the 70mm one more go using spot focus with aperture wide open at about 10ft distance from an AF target flat against a wall on a tripod with SR off (although I have found negligible difference on or off but you might as well eliminate any variables). Do multiple adjustments from -10 to +10 just to eliminate any errors and settle on the best focus. After you get spot focus dialed in try doing a 45 degree test just to check front and back focus.

I've found by giving the AF system fewer options for what to focus on you can get some nice results. Auto Area which you were using I reserve for moving objects such as birds in flight and aircraft and it works like a champ doing that.

[clackers]

In AF-C it´s working more or less good.Very curious since this is more complex.

Hi Licht,

Several things ...

What you've got to do to take advantage of eye detection is to choose Zone or Auto, make sure Subject Recognition is turned on in the menu, and that in the menu focus tracking is using both the focus points and exposure sensor.

You can check if your lens needs calibrating by comparing it with shots taken in Live View, which uses CDAF instead of PDAF. You say you're getting front focusing, so that's very possible.

Changing to Back Button Focus eliminates the chance of your photos being ruined by fumbled finger movements - if you're slow on the shutter the camera detects that as a half-press and will attempt to re-focus.

And of course, the central AF point is the most sensitive and is a cross point. The ones at the edges are always less accurate - mirrorless cameras suffer from having that sort over much of the frame.

[Eric Seavey]

Hello,

I must admit I´ve the same problem with myK3III….and – as written in a parallel thread - manly with the 16-50 PLM.
But all the other lenses show this inconsistent with OTHER AF than Spot/Centre Focus in AF-S.
In AF-C it´s working more or less good.Very curious since this is more complex.

But as @Eric Seavey I better choose AF-S for portraits since the movement (when “things” are slow and shutter speed high enough) because the AF-C really “Search” for movement and seems “disappointed” and fail often when things are not moving.

So all new features/grids/zones/auto-topics are not really reliable in my portrait work.

And now the news: I get my K3 III back from repair store (4 Weeks in repair!). On a small paper they wrote “Calibration” ….not more (I´m not a big fan of this very small communication of this service center here in Germany – but this is a different story).

But nothing changes this.

And since I read so much fantastic reviews of the new AF of the K3III I´m a little bit disappointed.

I often think I´m the only person with a Pentax who don´t use it for landscape an birds when I look at sample photos in the forum here ;-) But I think that is more or less the “problem” that it is not so easy or common to show friends/wife/children without their permission. So thanks to Eric Seavey: I´m not feeling alone.

Regarding my more or less parallel/similar problem written in the AF-S Select thread: When using outer AF points the failure is massive frontfocus, too!

And as well using this Zone AF: the points are showing that they find something (as in the portrait above I would say the middle of the body)…..but why is it totally out of focus? Ok the shutter was very slow as mentioned by another member, there might be some blur from movement….but you can see clearly at the ground the front focus. The leafs get sharper in front of the women (and I think it was only ONE example, and as me, he has a lot of more, otherwise he would not ask this)


So….I´m right before sending the 16-50PLMto services as well. Because it shows this very massive. I attached it for better comparison on my K3II. It´s not really good comparable, since the AF field is limited. But the front focus also behave when choosing outer AF-fields with really good contrast confirmation.

I´m now doing old fashion AF Spot/Center halfpressed and recompose…. But – as mentioned above: that’s not what I paid for.

---------- Post added 12-01-21 at 06:49 AM ----------

And I forget: this mentioned "5-point region (In think is called Select S)" doesn't´t work for me as well.


When I pout this "cross" on a face and half press, the cross changed only to the center point...ok...so far...so good.

But the face is not in focus!

When I use the normal Select with one AF filed, and have luck with an outer region: it´s better.

I don´t use this mode.

I thought in the beginning, that this works better with subject recognition, when there is really bad contrast or better nor edges ON ONE POINT...so It could help with the neighbor AF points...but not with faces :-(
or not with my camera :-(

I think I did come across your post, and was thinking you were having a similar problem as I am having. After doing multiple shoots, with full body, 3/4 and head shots. For head shots and 3/4 portraits, I found the single focus point on the eye working best. For full body shots, I am using the Select S (5-point focus) that has worked best when I put it in the center, and focus on the middle of the body. So, for me the Zone Select is useless for portraits.

In low light and/or low contrast situations, I am finding the 5-point to do a much better job at focusing. Last night I tested with a piece of paper on my desk in low light, and the single point did not focus, and just went from one end to the other end of the focus range. The 5-point did come into focus quickly.

---------- Post added 12-01-2021 at 06:34 PM ----------

I agree with @clackers. In AF mode you are giving the autofocus system too many options and from your rear lcd screen its clear to see that the system chose the center left of your model and not the model's face or eyes. Looks to me that the model's midriff area is most in focus right where the system says the focus was. Zone select will be your best option or AF Select.

You haven't said what technique you use to AF fine tune your lens but If I were you I'd give the 70mm one more go using spot focus with aperture wide open at about 10ft distance from an AF target flat against a wall on a tripod with SR off (although I have found negligible difference on or off but you might as well eliminate any variables). Do multiple adjustments from -10 to +10 just to eliminate any errors and settle on the best focus. After you get spot focus dialed in try doing a 45 degree test just to check front and back focus.

I've found by giving the AF system fewer options for what to focus on you can get some nice results. Auto Area which you were using I reserve for moving objects such as birds in flight and aircraft and it works like a champ doing that.

Indeed it seems that when I use the 5-point Select S option, I get best results for full body shots. And single point for head shots and 3/4 portraits, where I focus on the eyes. When I use any zone type instead of single point I seem to get front focus issues with any portraits, and so select the focus adjustment through trial and error in the field. At home I have a focus test page that I set up at a 45 degree angle with my camera pointed level at it, and adjust the camera placement such the what ever focus point I am testing is aligned with the center line on the test page. When I apply this procedure, the focus is spot on. So the front focus problem happens when I try to take photos of people using the zone. Other objects at any angle are nicely in focus.

---------- Post added 12-01-2021 at 06:55 PM ----------

Hi Eric,

In order, I think:

1. Set your shutter speed to around 1/200s even if you're using a tripod, that's a person you're shooting. 1/40s is not acceptable, they will move, even imperceptibly!

2. Set zone focus, on the head and let the K-3 III focus on her eyes for you, this is what you paid good money for! Make sure Subject Recognition is turned on in the menus.

3. If in style you are not a decisive shooter - there is a time gap between when you acquire focus and you actually take the shot - do AF-C instead of AF-S.

4. -10 for three lenses suggests there is a fault with your camera - return for exchange or repair within the warranty period.

Thanks for your suggestions. I have very rarely gotten movement blur from subjects at my shutter speeds, unless the subject moves a lot.
I tried the zone focus on the head and have not gotten good results. Seems that the single point on the eye works best. I have accidentally bumped the focus into AF-C and do not like it as the camera ends up hunting a lot. The -10 focus adjustment is for when I use any zone focus that involved portraiture, including Select S (5-point). Any other object seems to focus fine, which it really strange. I am almost tempted to reload the latest firmware.

[clackers]

I have accidentally bumped the focus into AF-C and do not like it as the camera ends up hunting a lot.

I actually use nothing but AF-C for portraits, there is really something going on here, if it's your technique or methods or the focus settings mentioned earlier, we just won't be able to tell here on the Internet, Eric!

The picture we saw was at 1/40s shutter speed, and the three red focus points indicated on the back of the screen were on a section of the subject's midriff, right? Nowhere near her head.

I can see you do wonderful astrophotography, by the way, Eric!

---

Last edited by clackers; 12-02-2021 at 03:49 PM.

[Eric Seavey]

I actually use nothing but AF-C for portraits, there is really something going on here, if it's your technique or methods or the focus settings mentioned earlier, we just won't be able to tell here on the Internet, Eric!

The picture we saw was at 1/40s shutter speed, and the three red focus points indicated on the back of the screen were on a section of the subject's midriff, right? Nowhere near her head.

I can see you do wonderful astrophotography, by the way, Eric!

Thanks!

I recently took some portrait photos again and this is now after I installed 1.31 firmware and I turned off facial recognition. The camera is focusing properly now (finally). I use the center 5 focus point region and this works well now. Of course I don't know if the focus improvement is related to the firmware upgrade or turning off the facial recognition, and I don't want to run the risk of getting blurry shots again, so I will leave it like this for now.

[licht96]

As I know, facial recognition has nothing to do with phase AF.
It's for Live view.

[clackers]

As I know, facial recognition has nothing to do with phase AF.
It's for Live view.

Not true, Licht! The K-3 III for example recognizes a face in the OVF and phase AF is used to focus on the eyes.

[Larrymc]

Not true, Licht! The K-3 III for example recognizes a face in the OVF and phase AF is used to focus on the eyes.

Agreed, you beat me to it Clack! The Mk III does a pretty good job of doing that.

[licht96]

I know.
But this are two topics.
For OVF "face detection" there is only
the menu point "subject recognition" - not mentioning the "face or eye".
Face recognition is for the contrast AF.
The face/eye detection should not change in OVF.

And apart from that... when it should be for Phase AF as well, than I'm wondering about Eric Seavy: "I recently took some portrait photos again and this is now after I installed 1.31 firmware and I turned off facial recognition. The camera is focusing properly now (finally)"

[clackers]

I know.
But this are two topics.
For OVF "face detection" there is only
the menu point "subject recognition" - not mentioning the "face or eye".

But it *is* eye if close enough, face if further away.

Check Kobie's (or anyone else's) videos if you don't believe.

As in the K-3 and K-1, the metering sensor's pixels are being used to scan for subjects like faces, but now there is triple the number of them.

[licht96]

Hmm..
@clackers: What is thee reason for our misunderstanding?
Are you a native English speaker? ...ah I see: you're living in Melbourne...so you are

I´m not...may be this is the reason, I can´t really write what I mean.

So:


I´m not negating that there is a facial/eye recognition in the K3 III !!!!!!!!


I´m only referring to the Eric Seavy “and I turned off facial recognition”

What menu point are we talking about?


....and what is the behavior of the camera to this....that was more or less the question to me.

After I was a little bit angry, that there is a misunderstanding in my post, I took my camera AND the manual....and that was good: because I was wrong! But not in the way you might think

In my knowledge you can influence the AF (and the algorithm behind it) in OVF in two ways: AF in AFC type 1 (I know, I know...the super resolution of the AE sensor is helping here **) and subject recognition to On.


The menu face detection is for Live view (On, Only in Auto area, Off)


There is also a menu called: Face priority AE...but this is in the manual explained in this way:
“To adjust the exposure for detected faces when [Multi-segment] is selected, set [Face PriorityAE] to [On] in the [Camera 2] menu”
So this has nothing to do with AF...it´s for exposure.

Coming to MY mistake: I thought, this last mentioned menu point is for the live view face detection. But the face detection of live view as it´s own menu point in the the live view AF settings.


So again: what menu point are we talking about, when Eric Seavy writes “and I turned off facial recognition” ?


In my knowledge it´s only "Subject recognition" that belongs to the enhanced features of the K3 III in OVF Phase.
And - as you referring to our lonely YT star Kobie ***- he mentioned this in his post as well as I now: there is no dedicated "Face detection" in the menu of the K3 III for OVF. It is more or less connected to "subject recognition".


I tried it:



AF in AFC Type 1, Subject recognition ON, Face priority AE ON => AF points are hunting for the eye
AF in AFC Type 1, Subject recognition ON, Face priority AE OFF => AF points are hunting for the eye (q.e.d. : only exposure is different)

AF in AFC Type 1, Subject recognition OFF, Face priority AE ON => AF points are hunting everything...but not specially the eye (q.e.d)

** I think we both had this discussion before in a different thread, that the K3II also has this subject recognition in the advertisement papers. We all knew the the amount of pixels are bigger now in the K3III...but first: 86000 pixel are quite enough to detect and analyses something...and second: as mentioned: they declared it in the K3II papers in the similar way: the AE sensor is "helping" the AF

***Kobie: when you read this: don´t get me wrong...it´s more or less the simple truth that for Pentax there are not really a big numbers of YouTubers

[Kobie]

Hmm..
@clackers: What is thee reason for our misunderstanding?
Are you a native English speaker? ...ah I see: you're living in Melbourne...so you are

I´m not...may be this is the reason, I can´t really write what I mean.

So:


I´m not negating that there is a facial/eye recognition in the K3 III !!!!!!!!


I´m only referring to the Eric Seavy “and I turned off facial recognition”

What menu point are we talking about?


....and what is the behavior of the camera to this....that was more or less the question to me.

After I was a little bit angry, that there is a misunderstanding in my post, I took my camera AND the manual....and that was good: because I was wrong! But not in the way you might think

In my knowledge you can influence the AF (and the algorithm behind it) in OVF in two ways: AF in AFC type 1 (I know, I know...the super resolution of the AE sensor is helping here **) and subject recognition to On.


The menu face detection is for Live view (On, Only in Auto area, Off)


There is also a menu called: Face priority AE...but this is in the manual explained in this way:
“To adjust the exposure for detected faces when [Multi-segment] is selected, set [Face PriorityAE] to [On] in the [Camera 2] menu”
So this has nothing to do with AF...it´s for exposure.

Coming to MY mistake: I thought, this last mentioned menu point is for the live view face detection. But the face detection of live view as it´s own menu point in the the live view AF settings.


So again: what menu point are we talking about, when Eric Seavy writes “and I turned off facial recognition” ?


In my knowledge it´s only "Subject recognition" that belongs to the enhanced features of the K3 III in OVF Phase.
And - as you referring to our lonely YT star Kobie ***- he mentioned this in his post as well as I now: there is no dedicated "Face detection" in the menu of the K3 III for OVF. It is more or less connected to "subject recognition".


I tried it:



AF in AFC Type 1, Subject recognition ON, Face priority AE ON => AF points are hunting for the eye
AF in AFC Type 1, Subject recognition ON, Face priority AE OFF => AF points are hunting for the eye (q.e.d. : only exposure is different)

AF in AFC Type 1, Subject recognition OFF, Face priority AE ON => AF points are hunting everything...but not specially the eye (q.e.d)

** I think we both had this discussion before in a different thread, that the K3II also has this subject recognition in the advertisement papers. We all knew the the amount of pixels are bigger now in the K3III...but first: 86000 pixel are quite enough to detect and analyses something...and second: as mentioned: they declared it in the K3II papers in the similar way: the AE sensor is "helping" the AF

***Kobie: when you read this: don´t get me wrong...it´s more or less the simple truth that for Pentax there are not really a big numbers of YouTubers

No worries, I got it right away. It is a lonely world out there in the PenTube verse lol

[Eric Seavey]

Thanks!

I recently took some portrait photos again and this is now after I installed 1.31 firmware and I turned off facial recognition. The camera is focusing properly now (finally). I use the center 5 focus point region and this works well now. Of course I don't know if the focus improvement is related to the firmware upgrade or turning off the facial recognition, and I don't want to run the risk of getting blurry shots again, so I will leave it like this for now.

My apologies folks, I meant subject recognition using OVF AF. I think it is supposed to work when using all or a zone of focus points and not a small zone of 5 focus points. I was having issues even with only 5 focus points, that seems to be corrected now. So perhaps it was the firmware update that fixed the problem, since subject recognition is not supposed to work with only 5 focus points. Am I correct? Has anyone else notice change in the AF performance after 1.31 firmware update?

[clackers]

AF in AFC Type 1, Subject recognition ON

Yes, that's it. And the subject is the face!

[Kobie]

My apologies folks, I meant subject recognition using OVF AF. I think it is supposed to work when using all or a zone of focus points and not a small zone of 5 focus points. I was having issues even with only 5 focus points, that seems to be corrected now. So perhaps it was the firmware update that fixed the problem, since subject recognition is not supposed to work with only 5 focus points. Am I correct? Has anyone else notice change in the AF performance after 1.31 firmware update?

The biggest change to the AF from my experience was with Firmware 1.2x. 1.31 seems to have improved eye detect AF in OVF shooting and better prediction when in Live View (less hunting and more accurate direction of driving the lens).

---------- Post added 02-16-22 at 06:46 PM ----------

I get what's being said regarding "Face Detection" regardless of OVF or Live View BUT, to eliminate confusion (or at least try to) let's just focus on the menu option naming specifically.
For OVF shooting, there is no option specifically called face detection. It just doesn't exist. Yes, there's subject recognition but Pentax does not state anywhere what subjects are actually being recognized. It may be a face, but maybe it's not and it's specifically looking for an eye, who knows.
Now in the menu for Live View shooting options, there is a specific Face Detection option.
The two systems have nothing to do with each other or they wouldn't be categorized separately as they are now.
1) Specific AF options for OVF.
2) Specific AF options for Live View.

You can test this yourself, turn on subject recognition and link the AF and AE sensors, leave face detect off for live view and see if it finds a face while shooting in live view.
Turn off subject recognition, unlink AF and AE sensor, turn on face detect for Live View and see if it detects a face while shooting in Live View ***Spoiler alert: it will***.
The two AF types can't be linked together because they use completely different sensors and methods for AF. OVF is a dedicated Phase Difference sensor (depth) and Live View is solely based on contrast directly from the image sensor.
Yes it's possible that in OVF it's detecting a face while using subject recognition, but the actual menu item called Face Detect only applies to the Live View options.