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06-12-2015, 02:27 PM   #1
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How much better is the AF tracking on the K-3 II?

I'm looking to get a K-3 II soon (my classic-model K-5 is starting to show its age) and I'm wondering how much of an improvement the AF tracking is on the K-3 II. I know AF on the K-5 is a far cry from that on K-3 II, but is there a substantial advantage over the original K-3?

I keep reading about AF tracking algorithm improvements especially with subjects moving directly towards the camera but I don't see any real measurements or reports about AF tracking performance. I suppose it's now fully predictive, but can anyone tell us about exactly how well it performs?

—DragonLord

06-12-2015, 02:44 PM - 1 Like   #2
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QuoteOriginally posted by DragonLord Quote
I'm looking to get a K-3 II soon (my classic-model K-5 is starting to show its age) and I'm wondering how much of an improvement the AF tracking is on the K-3 II. I know AF on the K-5 is a far cry from that on K-3 II, but is there a substantial advantage over the original K-3?

I keep reading about AF tracking algorithm improvements especially with subjects moving directly towards the camera but I don't see any real measurements or reports about AF tracking performance. I suppose it's now fully predictive, but can anyone tell us about exactly how well it performs?

—DragonLord
I'll have the camera on Tuesday so I should be able to test it then with the 150-450mm. I suspect that they've reduced the AF re-focusing latency, which is pretty high on the K-3. Will definitely get to test that theory

Adam
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06-13-2015, 03:11 AM   #3
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QuoteOriginally posted by Adam Quote
I'll have the camera on Tuesday so I should be able to test it then with the 150-450mm. I suspect that they've reduced the AF re-focusing latency, which is pretty high on the K-3. Will definitely get to test that theory
Interestingly that's exactly what I saw on 1.20 on the k3 less tendency to chase lock.

You could also improve lens hysteresis but that would need body and lens to work together (which may be why the newer lens are reportedly needed)

Would be interesting to compare
k3+1.21 and 150-450
k3ii and 150-450
k3+1.21 and da*300
k3ii and da*300

My gut feeling is the k3ii will only show any af-c advantage for use with 150-450 and both will be better than the k3+1.11
06-13-2015, 04:31 AM   #4
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QuoteOriginally posted by awaldram Quote
Interestingly that's exactly what I saw on 1.20 on the k3 less tendency to chase lock.

You could also improve lens hysteresis but that would need body and lens to work together (which may be why the newer lens are reportedly needed)

Would be interesting to compare
k3+1.21 and 150-450
k3ii and 150-450
k3+1.21 and da*300
k3ii and da*300

My gut feeling is the k3ii will only show any af-c advantage for use with 150-450 and both will be better than the k3+1.11
I upgraded prior to testing the lens, but the K-3 even with 1.21 can still use improvement overall. The first impressions review of the 150-450mm will include more details. I don't think the lens is to blame for any AF issues, but rather the camera.


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06-13-2015, 04:45 AM   #5
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Some of the scenarios I am interested in to test AF tracking are:

(1) simple regular motion tracking - (eg runner or cyclist coming directly towards the camera; model train going around on a circular track, aeroplane landing, motorcycle fast approaching camera) against a predominantly plain background (sky, grass, wall, road);

(2) tracking of a focus target in a cluttered scene - (eg individual football player with other players behind and around him, rodeo-rider with a very visible fence and contrasty crowd scene behind him; small bird moving through undergrowth). (cf Nikon's '3D tracking' system, Canon's 'Intelligent Tracking and Recognition' system);

(3) low-light, low-contrast tracking - any of (1) or (2) above, but under varying degrees of low or simply poor lighting, and/or simply scenarios with very low contrast subjects - eg subdued monotone lighting.
06-13-2015, 07:59 AM   #6
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I'd settle for a test of how well it can keep up with an active 3 year old like my son ��.

In all seriousness, this is the one area of the improvements that the K3 brings that I'm most interested in.

A question : does the K3 mk II have predictive focus tracking or just focus tracking?

Simon.
06-13-2015, 08:34 AM   #7
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QuoteOriginally posted by Srhphoto Quote
does the K3 mk II have predictive focus tracking or just focus tracking?
I believe the K-3 does try - depending on the AF area selection you made. If you told the camera to use only the single centre AF point, for example, predictive tracking won't happen because the camera won't be tasking the other AF points to collect any information about what the focus target is doing and 'feed' that data into the predictive tracking algorithm.

But if you selected, for example, Auto 27 points, Zone Select 9, or one of the Expanded Area AF modes (S/M/L), the camera will attempt to track (and anticipate to the degree necessary for the AF to be effective, I believe) movement within the specified AF area.

Useful info re the K-3's AF:
http://www.ricoh-imaging.co.jp/english/products/k-3/feature/02.html

Last edited by rawr; 06-13-2015 at 08:42 AM.
06-13-2015, 11:26 AM   #8
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QuoteOriginally posted by rawr Quote
I believe the K-3 does try - depending on the AF area selection you made. If you told the camera to use only the single centre AF point, for example, predictive tracking won't happen because the camera won't be tasking the other AF points to collect any information about what the focus target is doing and 'feed' that data into the predictive tracking algorithm.

But if you selected, for example, Auto 27 points, Zone Select 9, or one of the Expanded Area AF modes (S/M/L), the camera will attempt to track (and anticipate to the degree necessary for the AF to be effective, I believe) movement within the specified AF area.

Useful info re the K-3's AF:
Feature 2?K-3 | RICOH IMAGING
I think you've misunderstood what I mean. On other systems like Canon (I was a long time Canon user) predictive focus tracking (known as AI Servo on Canon) has nothing to do with the number of focus points active and works perfectly with a single focus point active. The focus system is able to determine the rate of change of distance relative to the camera and hence can 'predict' where to focus the lens to. This results in much improved continuous focusing on subjects coming towards or away from the camera. If the K3 or K3 mk II can't do this then it will never match Canon or Nikon in this regards.

The link makes no reference I can see to predictive focusing.

06-13-2015, 07:20 PM   #9
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QuoteOriginally posted by Srhphoto Quote
I think you've misunderstood what I mean. On other systems like Canon (I was a long time Canon user) predictive focus tracking (known as AI Servo on Canon) has nothing to do with the number of focus points active and works perfectly with a single focus point active. The focus system is able to determine the rate of change of distance relative to the camera and hence can 'predict' where to focus the lens to. This results in much improved continuous focusing on subjects coming towards or away from the camera. If the K3 or K3 mk II can't do this then it will never match Canon or Nikon in this regards.

The link makes no reference I can see to predictive focusing.
Well, Ricoh's own documentation says that it overhauled the AF.C algorithms to significantly improve AF tracking performance with subjects moving directly towards the camera:
QuoteQuote:
With Continuous AF (AF.C), tracking of subjects that move toward the depth direction is improved.
Given this, I have every reason to believe that the K-3 II has 3D predictive tracking. We just need someone to validate this belief.

The AF.S improvements are what are exclusive to a few newer lenses. Any AF lens should benefit from the new AF.C algorithms.

—DragonLord
06-13-2015, 07:45 PM   #10
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QuoteOriginally posted by Srhphoto Quote
The focus system is able to determine the rate of change of distance relative to the camera and hence can 'predict' where to focus the lens to.
AF prediction isn't magic. It needs data from the AF and a history of movement information, as Canon says: "With a predictive AF system the camera is continuously recording the position of the subject and predicting where it will be for the next frame based on its motion so far."

I've found (on paper) that the K-3/ K-3 II AF options look very similar to those of a 1Dx or 5D3 [PDF 430k].

The Pentax terminology may not match Canon, but the basics seem similar - eg Pentax says:
"PENTAX Real-time Scene Analysis System accurately detects the color, shape and movement of a subject, and keeps monitoring it throughout the imaging process"'

Canon says:
''To achieve the goal of optimum AF in diverse situations and lighting conditions, the EOS-1D X makes use of far more than just an autofocus sensor, as previous EOS cameras have done. Instead data is collected from the 61-point AF sensor, the auto exposure sensors, an AF correction light-source detection sensor and, with certain lenses, a panning detection gyro sensor. While these sensors provide a benefit to One-Shot AF shooting, the major benefit is found with AI Servo, where they can help identify the subject by not only contrast, but also colour. "

The Canon menu on, for example, the 7D2 certainly does, however, give the appearance of more control over AF tracking behaviour, but once again you can see similar concepts (AF hold behaviour, for example) at work in the K-3 settings. As the Canon 1 Dx docs themselves imply, earlier Canon's that just relied on the AF sensor alone couldn't really do AI servo predictive.

The key Canon concept with AI Servo 'predictive' AF - like with Nikon's '3-D tracking' predictive AF - is the integration of data from the various camera sensors - metering, AF, light source, gyro, focus distance (eg Canon has a list of lenses that work better than others in some AF modes, Nikon says G series lenses work best), panning mode etc etc - to make the AF algorithms more intelligent. In particular, better information to work with contrast and colour in moving subjects. This is what the Pentax K-3 system has also set out to achieve.



The Canon and Nikon AF systems are more evolved, esp on their pro bodies, but you can see Pentax is heading in the same direction.

Last edited by rawr; 06-13-2015 at 08:18 PM.
06-13-2015, 09:33 PM   #11
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I've been doing some non-scientific AF.S/C testing with birds in flight, cars and cyclists moving towards me or moving away, and cars driving by - I must say, the AF has improved a lot. So much so that I'm currently considering having the camera on AF.C on a regular basis.

I am so far very happy about the AF performance - I'll be shooting the first wedding with this camera next weekend, and by then I should get a much better clue about how the camera is.
06-13-2015, 11:17 PM   #12
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QuoteOriginally posted by Zafar Iqbal Quote
I've been doing some non-scientific AF.S/C testing with birds in flight, cars and cyclists moving towards me or moving away, and cars driving by - I must say, the AF has improved a lot. So much so that I'm currently considering having the camera on AF.C on a regular basis.

I am so far very happy about the AF performance - I'll be shooting the first wedding with this camera next weekend, and by then I should get a much better clue about how the camera is.
Your post history indicates that you moved up to the K-3 II from the K-30, whose AF is already superior to that of my K-5 😛

What's your keeper rate with fast-moving subjects of the sorts you've mentioned, and just how fast were they moving? I'd like to get a better sense of what to expect.

—DragonLord
06-14-2015, 03:09 AM - 1 Like   #13
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QuoteOriginally posted by Srhphoto Quote
I'd settle for a test of how well it can keep up with an active 3 year old like my son ��.

In all seriousness, this is the one area of the improvements that the K3 brings that I'm most interested in.

A question : does the K3 mk II have predictive focus tracking or just focus tracking?

Simon.
Yes, keeping up with a three year old is a serious test. Not just of the camera :-)

John.
06-14-2015, 03:22 PM - 1 Like   #14
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QuoteOriginally posted by DragonLord Quote
What's your keeper rate with fast-moving subjects of the sorts you've mentioned, and just how fast were they moving? I'd like to get a better sense of what to expect.
The birds were flocking in close proximity because of a man feeding them - a bunch would fly away from the man (toward my left) but then do a quick 180 turn to fly back towards him (my right). I mostly aimed for those birds from before they would turn, as I believe it's was more difficult than to follow a bird simply flying by.

These were shot using DA 50mm f1.8, which is a terrible lens when it comes to action - the lens also tend to place the focus either too far or too close.

The cars were moving at normal city speeds - 50km/h tops - with me on the side of the road. Most of the car photos were shot using 18-135, which also isn't a speedy lens - but these shots (in the album) are a mixture of tracking and dragging the shutter, so not the best examples.

Also, I never used burst in these shots - but I did with an approaching bus at another time. I fired 4 shots and all 4 where tack sharp - maybe luck, but the K-30 have trouble matching that rate.

I deleted lots of photos, even some properly focused ones. None of these were intended to be posted or anything like that - but I'll go out again soon and do better sample photos.

Click to enter the album:
06-15-2015, 05:37 PM   #15
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QuoteOriginally posted by Zafar Iqbal Quote
The cars were moving at normal city speeds - 50km/h tops - with me on the side of the road. Most of the car photos were shot using 18-135, which also isn't a speedy lens - but these shots (in the album) are a mixture of tracking and dragging the shutter, so not the best examples.
Funny that you should say that. DPReview found the 18-135 to be the best performing lens when they tested the K-3's AF tracking:

QuoteQuote:
We tested continuous focus with a variety of Pentax lenses, having discussed relevant settings with Ricoh. We used some lenses focused using the camera body's built-in motor (70mm Limited and HD 50-300mm), some with ring-type SDM motors (55mm and 50-135mm F2.8), and others with DC micromotors (18-135mm and 20-40mm Limited). Of these, the DC motor-based 18-135mm lens was the fastest to refocus and performed best in our tests.
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