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06-17-2015, 05:06 PM   #31
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QuoteOriginally posted by audiobomber Quote
My experience over the past two and a half years, shooting mostly BIF but also sports, is that your settings are robbing the K-3 of its ability to track. I agree with focus priority and continuous shooting. Try AF Hold HIGH and Expanded AF, and see the difference. Just make sure focus is locked on the target before you release the shutter, or you will have a string of misses.

Also, the 18-135mm almost never misses focus. Have you checked the calibration (AF Adjust)?
Thanks, I'll give it a try.

I used the 18-135mm extensively last time I was on a (month long) trip and there were no issues. This was together with K-30 and currently I haven't seen anything that gives me reason to believe I'm experiencing FF/BF issues. But I'll keep an eye out for it since it's on a different camera body now.


QuoteOriginally posted by Srhphoto Quote
On the cyclist example posted, I'm not surprised the AF struggled as there's really no areas of contrast for the AF system to work with. A black leather jacket and dark coloured trousers / skirt, coupled with what appears to be shooting into the light are really just setting the camera up to fail in my experience and opinion. The car example has more contrast, but you've again ahot into what looks to be a low angled sun which again robs the shot of contrast.

From these two examples, I'd be wary of drawing too many conclusions about the system being 'utter crap'. If you get similar results in decent light with a contrasty target, then I'd agree with you!

Simon.
I "hear" what you are saying but I do not agree. Ultimately you are or should be correct, but in the case of K-3 II and Sigma 70-200mm combi, it seems less contrast is better - I've uploaded more photos. I'll refer to the first set of settings mentioned in earlier post as Release Priority and the second set as Focus Priority:

zafariqbal.smugmug.com/Shares/2015/20150618



- Mercedes, Release Priority
- Bicyclist, Release Priority
- White car, Release Priority
- White car, Focus priority
- Bottle, Release Priority
- Barcode, Release Priority
- Sigma box, Release Priority

The barcode shots is the only series so far, where the focus didn't travel - it is at the same time also low contrasty - The Sigma Box however, just slightly more contrasty = bye bye focus. The white part is white, not reflection/specularity.

I did corresponding shots in Focus Priority - they are as one would expect. I also tried AF hold set to high - it "helped" in that the focus didn't travel to another galaxy - only to Pluto or in other words: still a lot.

My K-30 does a much better job in Release Priority and same lens.

06-17-2015, 07:38 PM   #32
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There is one thing I must call to attention regarding the AF array.

Notice that there is a significant gap between either side point and the main AF area. There are seven columns of selectable AF points, but nine columns of physical AF sensors:




This likely means that either
  1. there are invisible assist AF points between the center 5x5 grid and each edge point, which are used in AF.C but cannot be selected in AF.S, or
  2. the side AF points use two columns of AF sensors.
Questions, thoughts, or comments?

Edit: Just did some testing. Seems that void contains no active AF points at all. The extra columns appears to be unused.

—DragonLord

Last edited by bwDraco; 06-17-2015 at 07:54 PM.
06-18-2015, 02:48 AM   #33
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QuoteOriginally posted by DragonLord Quote
Questions, thoughts, or comments?
Note that within the AF assembly there are a few lenses that direct the light towards the AF chip, and shape and filter it too:

06-18-2015, 07:55 AM   #34
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QuoteOriginally posted by Zafar Iqbal Quote
Thanks, I'll give it a try.

I "hear" what you are saying but I do not agree. Ultimately you are or should be correct, but in the case of K-3 II and Sigma 70-200mm combi, it seems less contrast is better - I've uploaded more photos. I'll refer to the first set of settings mentioned in earlier post as Release Priority and the second set as Focus Priority:

.
Contrast has only a little relationship to phase or are you trying to use LV for Tracking ?

https://cdn.photographylife.com/wp-content/uploads/2012/07/Phase-Detection-Autofocus.png
https://photographylife.com/how-phase-detection-autofocus-works

06-18-2015, 08:10 AM   #35
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QuoteOriginally posted by audiobomber Quote
Pentax should provide more detailed instructions on using the AF-C settings. We're all just working with trial and error.
I strongly agree. A collection of white papers on the more sophisticated features is long overdue. A short list might include:
  • SR
  • Multi-flash P-TTL
  • K-3 auto multi white balance
  • K-3 AF-C
  • Pixel Shift


Steve
06-18-2015, 08:13 AM   #36
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QuoteOriginally posted by awaldram Quote
But in fairness their forums are just as full of miss set cameras being 'rubbish' so maybe wasted expense.
So true, so verrrrry true.


Steve
06-18-2015, 08:22 AM   #37
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QuoteOriginally posted by awaldram Quote
Contrast has only a little relationship to phase
...and phase has little relationship to phase. The term is a bit of a misnomer. The closest familiar analogy to PDAF is a dual image rangefinder. For sure, it is curves that are matched, but if the curves are "flat"/"noisy" (low contrast or low light) the system will be unable to consistently determine the matched state.


Steve
06-18-2015, 08:42 AM   #38
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QuoteOriginally posted by stevebrot Quote
I strongly agree. A collection of white papers on the more sophisticated features is long overdue. A short list might include:
  • SR
  • Multi-flash P-TTL
  • K-3 auto multi white balance
  • K-3 AF-C
  • Pixel Shift


Steve
Education is a critical part of sales. I would benefit Pentax if they did more of it.

06-18-2015, 12:24 PM   #39
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QuoteOriginally posted by awaldram Quote
Contrast has only a little relationship to phase or are you trying to use LV for Tracking ?
That has been my initial understanding of PDAF as well - I haven't attempted using LV - it's of little interest to me.
06-18-2015, 04:25 PM   #40
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"Although on paper, thePentax K-3 II promises to bring undisclosed improvements to AF-C performance, we did not observe any evidence of faster focusing, lower latency, or quicker target re-acquisition with the K-3 II"
Right from the review of D FA 150-450mm. Sounds like part of the question is answered in the review

Thanks

Randy
06-18-2015, 07:38 PM   #41
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QuoteOriginally posted by slip Quote
Right from the review of D FA 150-450mm. Sounds like part of the question is answered in the review
Well, to be fair to the lens and camera , the reviewer may not have had access to both for very long. Getting the two complex instruments to really work together probably takes a while.

I know from my own experience with the K-3, and lesser lenses like the Sigma 70-200 HSM II, even after shooting that combo for over a year, I'm still learning how to get the most out of them as a unit. Every shoot requires parameter tuning to get things set optimally, particularly if you are shooting a venue or event style - eg motorcycle vs rodeo vs rally cars - you haven't shot before.

FWIW, Barry Pearson, shooting with the K-3II and 150-450, as seen in the other site (thousands of DNG's at airshows and motor racing, for example) gives the impression that he finds the K-3II drives things better than it's predecessor.
06-19-2015, 08:10 AM   #42
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I'm new to the K3II having just upgraded from a K5 and I would like to see a dedicated thread on recommended settings for the K3II for a wide variety of subjects such as BIF, Sports, Weddings etc. As suggested a white paper on focus settings would be an excellent beginning.
06-20-2015, 07:12 AM   #43
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QuoteOriginally posted by DragonLord Quote
There is one thing I must call to attention regarding the AF array.

Notice that there is a significant gap between either side point and the main AF area. There are seven columns of selectable AF points, but nine columns of physical AF sensors
So you are assuming that the number of columns on the AF sensor corresponds to the number of columns of AF points in the viewfinder. I don't think that's necessarily the case, as explained e.g. here: Canon EOS DSLR Autofocus Explained
06-20-2015, 11:26 AM   #44
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I had K-5 II before K-3 II. I think the Af tracking is much improved on K-3 II. I shot this with DA 35mm f2.4, I cropped it about 50-60% and I resized it to 2048mpx.

I took about 6-7 picture in continuous shooting mode and al of them were in focus.

Exif: ISO 200, f4, 1/5000 Click on the image to see it bigger and remember, this picture was already been cropped.

06-20-2015, 12:35 PM   #45
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QuoteOriginally posted by bobell69 Quote
I'm new to the K3II having just upgraded from a K5 and I would like to see a dedicated thread on recommended settings for the K3II for a wide variety of subjects such as BIF, Sports, Weddings etc. As suggested a white paper on focus settings would be an excellent beginning.
Good idea Bob

I have one on order and will be coming from the K5. How many user modes are on the K3II as with my K5 I have set up all my preferred settings outside of my usual default TAV mode setting in the 5 User modes.

Hope you are enjoying your new camera mate

cheers

Neil
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