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11-10-2013, 04:23 AM   #31
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Just thinking about the car sequence. Won't there be a finite time between aquiring focus and capturing the image, during which the car has moved. A slow shutter speed equals more time, also was the camera set to focus release or shutter release priority - might make a difference.

25 mph equals 36 Feet per second.

Jeff


Last edited by screwdriver222; 11-10-2013 at 06:34 AM. Reason: additional info
11-10-2013, 06:40 AM   #32
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QuoteOriginally posted by Adam Quote
pdaf: (k3 = k-5 ii) > k-5
cdaf k-3 > (k-5 ii = k-5)
AF-C: K-3 > K5 II > K-5

QuoteOriginally posted by zapp Quote
I for myself started looking at Olympus OM-D, but still appreciate the feel of my Pentax lenses and the sensor size over it... Before I buy, I will test the K3 in a shop quite thorougly - Pentax at least lost its legacy as a quality brand for me.
I agree about the K-5 performance, but Olympus is the wrong place to shop if you want AF-C and tracking. I've seen threads at DPR complaining about poor AF. Nothing they have will match a K-3 for action or low light.

Last edited by audiobomber; 11-10-2013 at 04:30 PM.
11-10-2013, 07:08 AM   #33
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So far may experience with K-3 - excellent. The detail is superb and the auto focus seems there it is just a matter of understanding the settings and Pentax providing much better guidance and some application notes and videos. When I get out shooting 8 fps 2m mpixel raw with the detail of the K-3 and good auto focus - I feel other camera owners will be envious. Today I am going back out to shoot more moving cars and vary some of the settings based on the comments from forum members.
11-10-2013, 07:17 AM   #34
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QuoteOriginally posted by Rich M Quote
Adam.....it seems to me that the PDAF is the same speed as the K-5 iiS.......but the (and I hope I am stating this correctly) focus acquisition is more accurate.

That impression in just a few days use.

R
This next Tuesday, or maybe the one after that, I'll get to take my K-3 for an event shoot for some truly torturous low-light AF testing. I'll make sure to write about my experiences then

11-10-2013, 07:31 AM   #35
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QuoteOriginally posted by Digitalis Quote
Another AF related query I have : is the screwdrive AF any quieter on the K3 than the K5? I'm gathering quite a collection of photographs of startled wildlife:
Nice captions.

Near as I can tell (mainly on DA & FA Limiteds) there is no real difference in the sound of screwdriven AF from the K-5 to K-3, just that it moves a little faster and hunts less (this with the 35 Macro, so long focus throw). Most likely any sonic improvement in the AF motor won't be discernible over the mechanical sound of the lens gears...
11-10-2013, 09:23 AM   #36
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QuoteOriginally posted by bossa Quote
I'm interested to hear what AF Fine Adjustments people have made with the K-3 and how they differ to what they did with the K-5. A number of people here have stated that they have needed no AFFA with their K-5II cameras and so I'm wondering if the K-3 holds to that tradition.
Here is my test results: https://www.pentaxforums.com/forums/172-pentax-k-3/242062-k-3-af-testing.html
11-10-2013, 10:23 AM   #37
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QuoteOriginally posted by screwdriver222 Quote
Just thinking about the car sequence. Won't there be a finite time between aquiring focus and capturing the image, during which the car has moved. A slow shutter speed equals more time, also was the camera set to focus release or shutter release priority - might make a difference.

25 mph equals 36 Feet per second.

Jeff
Yes, but one of the benefits of predictive AF is that a tracked subject, at least one with a steady speed, can have it's future position estimated and the AF delay allowed for so that the shot is in focus. It's all down to clever algorithms, so the question is - does the K-3 have them?
11-10-2013, 10:48 AM   #38
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Much better results today shooting moving cars.
Revised car sequence viewable here: https://www.dropbox.com/sh/h67gsvyfbs8w14r/Fl2ottiRe5/JPEG
I revised the settings for shooting cars as an auto focus test and I feel the results are good. You can see a 20 shot sequence here https://www.dropbox.com/sh/h67gsvyfbs8w14r/Fl2ottiRe5/JPEG
The settings:
Shooting in RAW = Photoshop JPEG conversion with no PP
TAV 1/2000 sec f4 using DA*300 - personally I prefer TAV which is the mode I use shooting wildlife.
all auto focus menu items set to 1 -- that is Menue Items C 15, 16, 17 and 18 set to default 1
Focus area is SEL L all the points used with the center point selected

I also tried setting the Action in AF.C Continuous (menu item C 17) option to AUTO(setting=2) and FPS(setting=3) and feel focus priority, setting =1, gave me what I wanted. Personally a few less shots in focus, especially with the speed of the K-3, is better than more shots. I will see how this works in practice shooting birds.

11-10-2013, 01:54 PM   #39
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Slower Birds than Cars but still interresting test, pictures available here :
Pentax K3 Experience - a set on Flickr

Pentax K-3 AutoFocus Test with Pentax 50-135mm Lens. SOOC shots, no corrections except the lens correction. AF-C with HOLD AF set on medium, burst priority and 9 points Selective AF. AF burst mode on High (8,3 FPS). 1/500sec
Swan coming straight at me I should have increase to at least 1/1000 sec to have some cleaner shots.

22 consecutive shots with almost perfect AF tracking




Crop :

11-10-2013, 03:11 PM   #40
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Thanks DimC and Bob - amazing shots. Noted that DimC shots were at 8.3 fps and 1/500s on a 50-135 lens no less.

The old bugaboo about Pentax and tracking focus is no more. I gotta have this camera.
11-12-2013, 02:47 AM   #41
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QuoteOriginally posted by jatrax Quote
Cheers
11-12-2013, 03:06 AM   #42
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Just read the review on this site and the AF keeper rate seems really low really surprised at that but it's just one test
11-12-2013, 12:33 PM - 1 Like   #43
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The AF analysis on the Pentax Forums K3 review is blatantly unfair and clearly the worst part of the review:

QuoteQuote:
To test the K-3's high-speed focusing capabilities, we subjectively compared the K-3 to the K-5 II (w/ Pentax 60-250mm F4) and the Nikon D610 (w/ Nikon 70-200mm 2.8)
The review goes on to say that the K3 tracking "is not up the competition" when what the author is really saying is that the K3 tracking with a slow, f4, zoom is not as good as a FF D610 with an F2.8 lens. They only compared the K3 to one FF camera and one fast lens, and yet extrapolate that to all the "competition". The author has excluded any Canon, Sony or other aps sensor cameras from the review, so to imply that some sort of comprehensive comparison was done is not accurate.

I wouldn't be surprised that the firmware won't be honed further for the K3, and the 2 series of BIF pictures above are terrific.

Also, i'm probably going to buy the K3 based on its terrific low light focusing capabilities, -3ev. So there is more to autofocusing performance that just tracking capabilities. But the author doesn't seen to care about other attributes of AF such as accuracy/low-light and dismisses K3 performance out of hand.

I think the IQ comparisons part of the PF review is outstanding, but i suggest PF members go elsewhere for a more objective review of the K3's autofocus attributes.

Last edited by philbaum; 11-12-2013 at 12:40 PM.
11-12-2013, 12:52 PM   #44
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QuoteOriginally posted by philbaum Quote
a more objective review of the K3's autofocus attributes
I think the issue is not objectivity, but rather capacity to test accurately, especially given the rich capabilities of the camera.

Normally it's hard enough simply to do lens testing for front/back focus accurately, let alone AF performance testing, given all the variables involved: lenses, shooting scene, AF settings, and more. Now with the K3, given that it has about 900 different AF modes, where do you start?
11-12-2013, 01:34 PM   #45
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QuoteOriginally posted by rawr Quote
I think the issue is not objectivity, but rather capacity to test accurately, especially given the rich capabilities of the camera.

Normally it's hard enough simply to do lens testing for front/back focus accurately, let alone AF performance testing, given all the variables involved: lenses, shooting scene, AF settings, and more. Now with the K3, given that it has about 900 different AF modes, where do you start?
I agree with you, it would take a lot of time and resources. But then one shouldn't word the review with grandiose statements that imply a comprehensive review was done. People do a lot of scanning information these days and already some comments to the review are stating that they won't buy the K3 because of the conclusion that the AF is not up to the competition.

I actually searched dpreview to see if any other cameras list their lowest light density for focusing and couldn't find any of the 4 or 5 reviews i looked at (mostly FF cameras) that indicated how the K3 will compare to other cameras. The K3 may have class winning attributes in this category, but all readers of the PF review will conclude is that K3 lacks in all AF areas.

There is nothing wrong in doing a limited review and then stating what the limitations are. The IQ comparison i thought was very well done and must have required many hours. So i don't mind limitations, but don't state that the camera was "not up to the competitions" when the data doesn't support that broad conclusion and its only for one attribute=tracking with one camera and one lens (and one bicycle :-))
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