K-3 AF-C Test Picts

Winder · 11-02-2013, 04:51 PM

Originally posted by rawr

A useful set of tests and good results.

I suspect single centre point AF is not the best option for AF-C tracking.

In the Canon 1Dx AF settings User Guide, which is 1Dx focussed but a good guide to sports AF-C settings generally, they say:

One of the K-3's 'Expanded Area AF' or 'Zone Select' options may work better. They seem very similar to the 1Dx's 'AF Point Expansion' mode options.

Pentax need to put out a book on the new AF features. They have a lot of nuances, I suspect.

Yes. I definitely should have played with more of the AF zone features. I was shooting at F/2 or F/2.8 though and only the center 3 sensors are F/2.8 sensors. Most people however will be shooting at F/5.6 and could use the zone AF system. I was trying to challenge they system by using wider aperture (narrower DoF).

jaad75 · 11-02-2013, 05:32 PM

Originally posted by Winder

I was shooting at F/2 or F/2.8 though and only the center 3 sensors are F/2.8 sensors. Most people however will be shooting at F/5.6 and could use the zone AF system

Only center points have f/2.8 baseline, but it does not mean, that the rest of them can't be used with that aperture. It just means they have narrower baseline and slightly less precision. BTW, judging from some marketing materials, only the horizontal pair of sensors have a wider f/2.8 baseline, vertical pair uses narrower f/5.6 baseline only, so basically those "points" work on f/5.6 precision and use an additional f/2.8 pair of sensors as a support when the system needs more precision with faster lens. I even doubt if they are used in the AF-C mode where the AF system is tuned for speed rather than accuracy.

richard balonglong · 11-02-2013, 08:49 PM

Wow!
The AF-C really improves! I like!
Looking at the exposures of your photo, what was your Mode and what was your EV? By the looks of it, the photos (second batch) over exposes then was toned down through post-process... In short, how do you find the K-3's exposure metering in high contrast situation? =)

alcstudios · 11-02-2013, 09:55 PM

Thanks for posting these shots, my K3 will be here Wednesday, from the look of your photos the AFC looks much improved over my half worn out K7

bgdisc · 11-02-2013, 10:53 PM

It looks like the K-3 should be able to handle American Football (College, Division 1). I miss a lot of shots with my K-5 because the AF just can't keep up. Thanks for testing and sharing your results.

Winder · 11-04-2013, 07:54 AM

Originally posted by bgdisc

It looks like the K-3 should be able to handle American Football (College, Division 1). I miss a lot of shots with my K-5 because the AF just can't keep up. Thanks for testing and sharing your results.

I think the camera is more than capable of handling football. I was using the center AF point and and playing with the settings. The area AF would be great for large field sports. The only limitation now is lens speed.

Vaikis_ · 11-04-2013, 08:39 AM

I would like to see how AF-C performs doing panning pictures, who can try ?

Winder · 11-04-2013, 08:59 AM - **1 Like**

Originally posted by Vaikis_

I would like to see how AF-C performs doing panning pictures, who can try ?

How is this?

jaad75 · 11-04-2013, 09:13 AM

Your object was at the same distance so it could be easy done with an old AF-C or even AF-S.

Andi Lo · 11-04-2013, 09:36 AM

Originally posted by jaad75

Your object was at the same distance so it could be easy done with an old AF-C or even AF-S.

Even minimal distance changes will make shots unsharp if shot with long FL / wide aperture (which he is doing in theses shots)

Great results on the K-3, looks very solid

wpompen · 11-04-2013, 10:14 AM

I can't wait to test the K-3 AF-C on a pack of sighthounds, already know my K5 is not keeping up at all! ;-)

jaad75 · 11-04-2013, 10:47 AM

Originally posted by Andi Lo

Even minimal distance changes will make shots unsharp if shot with long FL / wide aperture (which he is doing in theses shots)

Really? :P I could track birds in flight with rather poor AF-C of my K-5IIs with the DA*200 wide open. If the object moves across the frame at a constant distance it's not a challange for any AF system.

Winder · 11-04-2013, 10:53 AM

Originally posted by jaad75

Your object was at the same distance so it could be easy done with an old AF-C or even AF-S.

No, he was not the same distance, and at F/2.8 the DoF of the 85mm is pretty narrow. I was standing in a turn where the rider was approaching at 120 degrees and turned and headed away at 90 degrees to my right.

JinDesu · 11-04-2013, 10:59 AM

The distance changed from the first shot.

jaad75 · 11-04-2013, 11:05 AM

Originally posted by Winder

No, he was not the same distance

The distance change looks pretty small anyway.

Originally posted by Winder

and at F/2.8 the DoF of the 85mm is pretty narrow

It's not that narrow, but narrow enough to show some errors.
I'm still waiting for samples of K-3 tracking subjects in erratic movement.

11-02-2013, 08:49 PM	#33
richard balonglong Veteran Member Join Date: Aug 2007 Location: Baguio City, Philippines Photos: Gallery Posts: 350	Wow! The AF-C really improves! I like! Looking at the exposures of your photo, what was your Mode and what was your EV? By the looks of it, the photos (second batch) over exposes then was toned down through post-process... In short, how do you find the K-3's exposure metering in high contrast situation? =) Last edited by richard balonglong; 11-02-2013 at 08:59 PM.

11-04-2013, 10:14 AM	#41
wpompen Forum Member Join Date: Mar 2013 Posts: 64	I can't wait to test the K-3 AF-C on a pack of sighthounds, already know my K5 is not keeping up at all! ;-) Last edited by wpompen; 11-04-2013 at 10:14 AM. Reason: typo

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11-02-2013, 04:51 PM	#31
Winder Veteran Member Join Date: Apr 2010 Location: Tennessee Posts: 6,617 Original Poster	Originally posted by rawr A useful set of tests and good results. I suspect single centre point AF is not the best option for AF-C tracking. In the Canon 1Dx AF settings User Guide, which is 1Dx focussed but a good guide to sports AF-C settings generally, they say: One of the K-3's 'Expanded Area AF' or 'Zone Select' options may work better. They seem very similar to the 1Dx's 'AF Point Expansion' mode options. Pentax need to put out a book on the new AF features. They have a lot of nuances, I suspect. Yes. I definitely should have played with more of the AF zone features. I was shooting at F/2 or F/2.8 though and only the center 3 sensors are F/2.8 sensors. Most people however will be shooting at F/5.6 and could use the zone AF system. I was trying to challenge they system by using wider aperture (narrower DoF).

11-02-2013, 05:32 PM	#32
jaad75 Veteran Member Join Date: Sep 2007 Location: Cracow Posts: 457	Originally posted by Winder I was shooting at F/2 or F/2.8 though and only the center 3 sensors are F/2.8 sensors. Most people however will be shooting at F/5.6 and could use the zone AF system Only center points have f/2.8 baseline, but it does not mean, that the rest of them can't be used with that aperture. It just means they have narrower baseline and slightly less precision. BTW, judging from some marketing materials, only the horizontal pair of sensors have a wider f/2.8 baseline, vertical pair uses narrower f/5.6 baseline only, so basically those "points" work on f/5.6 precision and use an additional f/2.8 pair of sensors as a support when the system needs more precision with faster lens. I even doubt if they are used in the AF-C mode where the AF system is tuned for speed rather than accuracy.

11-02-2013, 09:55 PM	#34
alcstudios Senior Member Join Date: Sep 2011 Location: Texas Photos: Albums Posts: 146	Thanks for posting these shots, my K3 will be here Wednesday, from the look of your photos the AFC looks much improved over my half worn out K7

11-02-2013, 10:53 PM	#35
bgdisc Forum Member Join Date: Dec 2010 Location: United States Photos: Gallery Posts: 95	It looks like the K-3 should be able to handle American Football (College, Division 1). I miss a lot of shots with my K-5 because the AF just can't keep up. Thanks for testing and sharing your results.

11-04-2013, 07:54 AM	#36
Winder Veteran Member Join Date: Apr 2010 Location: Tennessee Posts: 6,617 Original Poster	Originally posted by bgdisc It looks like the K-3 should be able to handle American Football (College, Division 1). I miss a lot of shots with my K-5 because the AF just can't keep up. Thanks for testing and sharing your results. I think the camera is more than capable of handling football. I was using the center AF point and and playing with the settings. The area AF would be great for large field sports. The only limitation now is lens speed.

11-04-2013, 08:39 AM	#37
Vaikis_ Senior Member Join Date: Oct 2008 Posts: 213	I would like to see how AF-C performs doing panning pictures, who can try ?

11-04-2013, 09:13 AM	#39
jaad75 Veteran Member Join Date: Sep 2007 Location: Cracow Posts: 457	Your object was at the same distance so it could be easy done with an old AF-C or even AF-S.

11-04-2013, 09:36 AM	#40
Andi Lo Veteran Member Join Date: Jul 2008 Location: Halifax, Nova Scotia Posts: 2,924	Originally posted by jaad75 Your object was at the same distance so it could be easy done with an old AF-C or even AF-S. Even minimal distance changes will make shots unsharp if shot with long FL / wide aperture (which he is doing in theses shots) Great results on the K-3, looks very solid

11-04-2013, 10:47 AM	#42
jaad75 Veteran Member Join Date: Sep 2007 Location: Cracow Posts: 457	Originally posted by Andi Lo Even minimal distance changes will make shots unsharp if shot with long FL / wide aperture (which he is doing in theses shots) Really? :P I could track birds in flight with rather poor AF-C of my K-5IIs with the DA*200 wide open. If the object moves across the frame at a constant distance it's not a challange for any AF system.

11-04-2013, 10:53 AM	#43
Winder Veteran Member Join Date: Apr 2010 Location: Tennessee Posts: 6,617 Original Poster	Originally posted by jaad75 Your object was at the same distance so it could be easy done with an old AF-C or even AF-S. No, he was not the same distance, and at F/2.8 the DoF of the 85mm is pretty narrow. I was standing in a turn where the rider was approaching at 120 degrees and turned and headed away at 90 degrees to my right.

11-04-2013, 10:59 AM	#44
JinDesu Veteran Member Join Date: Jun 2011 Location: New York City Photos: Gallery Posts: 5,638	The distance changed from the first shot.

11-04-2013, 11:05 AM	#45
jaad75 Veteran Member Join Date: Sep 2007 Location: Cracow Posts: 457	Originally posted by Winder No, he was not the same distance The distance change looks pretty small anyway. Originally posted by Winder and at F/2.8 the DoF of the 85mm is pretty narrow It's not that narrow, but narrow enough to show some errors. I'm still waiting for samples of K-3 tracking subjects in erratic movement.

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