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11-07-2013, 10:41 PM - 1 Like   #1
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Autofocus accuracy - K3 vs K5II vs K5 ?

I'm not fussed about AF speed and don't mind post-processing for sharpness etc, but with ever-decreasing eyesight, I rely heavily on AF and am tired of going GRRR at missed focus on my otherwise much-loved K5.

It seems from some of the reviews that the K3 is better at capturing birds in branches and eyes in faces.

So all you lucky early adopters, when you have had some time to play - compared to the K5, is the autofocus so significantly more accurate that my bank balance may have to go red?

And similarly, how is the K3 AF accuracy compared to the K5II?

11-07-2013, 10:53 PM   #2
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QuoteOriginally posted by vrphoto Quote
i'm not fussed about af speed and don't mind post-processing for sharpness etc, but with ever-decreasing eyesight, i rely heavily on af and am tired of going grrr at missed focus on my otherwise much-loved k5.

It seems from some of the reviews that the k3 is better at capturing birds in branches and eyes in faces.

So all you lucky early adopters, when you have had some time to play - compared to the k5, is the autofocus so significantly more accurate that my bank balance may have to go red?

And similarly, how is the k3 af accuracy compared to the k5ii?
pdaf: (k3 = k-5 ii) > k-5
cdaf k-3 > (k-5 ii = k-5)

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11-07-2013, 11:11 PM   #3
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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
11-08-2013, 12:04 AM   #4
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Focus accuracy is stellar in both my K-5II cams. I don't think it could be any more accurate.

11-08-2013, 12:10 AM   #5
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QuoteOriginally posted by krebsy75 Quote
Focus accuracy is stellar in both my K-5II cams. I don't think it could be any more accurate.
I think it could in other situations than the ones you're using. K-3 focus system has smaller focus points which can help in many situations. That I see as the major improvement and not the increase in number of focus points.
Best regards,
Ciprian
11-08-2013, 12:13 AM - 1 Like   #6
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to be honest i would love to keep my k5 but the AF is ruining my fun
I can put on 50mm 1.4 and it will be perfect outside but under lights inside the house i have to dial in -7
this goes for just about all lenses that are fast enough to notice difference
had body repaired, replaced, they all do the same, I even demonstrated the issue to pentax tech and all he had to offer was puzzled face
as is i feel ripped off that i have to spend money on upgrade i don't want or need but if i do would hate to face same problems so i'm very happy to see this thread.
would love someone with pentax FA 50mm 1.4 do some shots wide open outdoor and indoors under tungsten light with no sunlight around coming in via windows, is there difference in FF/BF?
11-08-2013, 01:56 AM   #7
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QuoteOriginally posted by Croc Quote
indoors under tungsten light
The K-3 should not have that problem. Every DSLR from the K-30 onwards - K-30, K-5II, K-50 - had that problem fixed. A whole new AF assembly was implemented to deal with that problem in those bodies, and the K-3 has an even newer, more sophisticated AF and metering system.
11-08-2013, 02:27 AM   #8
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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.

11-08-2013, 04:08 AM   #9
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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.
On my K5 I had to fine tune all my lenses, from -5 to -11.

On the K-3 I did fine tune the Sigma 17-70mm by -3, Pentax 50-135mm by -5 and Tamron 90mm by -2.
Pentax "plastic wonder" came out great, no fine tune.
11-08-2013, 06:04 AM   #10
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I'm beginning to suspect it is lens dependent. A quick try of each, longer with the DA*300. Compared to the K-5

F100 2.8 screw drive: positive but no quicker.
DA*300 Like a new lens. Positive, quick. I got used to hearing the mechanism on my K-5, but i haven't heard it operate on the K-3.
DA L 55-300: On the K-5 i sounded and acted like a reciprocating band saw. Same speed but doesn't hunt.
DA12-24 positive. Not a tough one to focus; set it to f8.
DAL 18-55 positive.

The screw drive lenses feel faster because it isn't doing it three times. The mechanism is no quicker. Except for CDAF. On the K-5 the CDAF was slow, about half speed. Now it seems to be as fast as the PDAF.

I haven't tried my Sigma 150-500, it is too dark and overcast, but others have had success.

I think the problem now is with lenses. The smaller focus point helps considerably, and the low light capability is remarkable. Are the other SDM lenses improved?
11-08-2013, 06:10 AM   #11
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QuoteOriginally posted by DimC Quote
On my K5 I had to fine tune all my lenses, from -5 to -11.

On the K-3 I did fine tune the Sigma 17-70mm by -3, Pentax 50-135mm by -5 and Tamron 90mm by -2.
Pentax "plastic wonder" came out great, no fine tune.
Cheers. That's good to know.
11-08-2013, 06:26 AM   #12
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I just got my K3 last night, charged new batteries, put on the DA*300 and went to my street corner to photograph moving cars. The first sequence is a car coming directly toward the camera, the second sequence the car is coming towards and across the camera. In the past the DA*300 on my K5 was slow, not so on the K3 - not instantaneous but noticeably faster and certain. No processing other than converting DNG to JPEG. I set the focus points to the middle selection. The last shot is a third sequence bu the forum limited the attachments to 10.
I still need to go through and learn about the auto-focus options and how best to set up the K3
I would estimate the speed of the cars to be 25 mph perhaps 30
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11-08-2013, 11:42 AM   #13
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All the non-BMW shots have focused where the car used to be 1/3 second before the shutter tripped. I base that on the fact that the focus point is about a car length or so behind the front grill, say 15ft and 30mph is 44ft per second, so 15/44sec. What happened to predictive AF?
11-08-2013, 11:46 AM   #14
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Cars License numbers

Thanks for the shots. The last 2 look OOF. What was the focus point?
However in my humble opinion you might want to remove the pics before the car owner stumbles upon his cars license numbers out in public domain
Or you can blacken the number plates at the least
11-08-2013, 12:25 PM   #15
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QuoteOriginally posted by SteveB Quote
All the non-BMW shots have focused where the car used to be 1/3 second before the shutter tripped. I base that on the fact that the focus point is about a car length or so behind the front grill, say 15ft and 30mph is 44ft per second, so 15/44sec. What happened to predictive AF?
I will need to read more about setting up AF on the K-3
The auto-focus section in the manual seems a little sparse to me and an area that deserves more explanation.

Since the BMW came out ok then I would guess it was me with the second car.

I set the focus on continuous, high speed. I see that I had AF set to AF.A and so I will retry with AF.C, the setting focusing area was set to zone, first frame action #16 set to focus priority, action in af.c set to focus priority, i had #18 hold af status set to default 1which is none. I am changing to 3 medium

privacy - traveling on public road means you give up privacy - I think
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