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05-21-2016, 10:33 PM   #46
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QuoteOriginally posted by Digitalis Quote
we are talking about the Pentax D-FA 15-30mm f/2.8 on the K-1 here - a completely different lens.
Yes. And I am starting to wonder if it's lens dependent. Am I asking too much of a 15mm lens to repeatedly hit correct focus at infinity? The details are so small. I don't have another lens to test, only my 645 kit.

The myth of set and forget focus with ultra wides does not apply here, I don't know how it ever did, especially not with these new high res sensors. Even a slightly miss focused shot at f5.6 at 20m will look not ultimately sharp as it could.

05-21-2016, 11:10 PM   #47
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QuoteOriginally posted by 2351HD Quote
Am I asking too much of a 15mm lens to repeatedly hit correct focus at infinity?
The only K mount AF lens I have in this focal length range is the Sigma 15-30mm f/3.5-5.6 and it focuses with reasonable accuracy - providing you use manually selected focus points* on the K-1. You even need to do this with the Nikon D3 with the 14-24mm f/2.8, that lens can only consistently focus with AF at infinity is through using manual AF point selection.

*preferably, one of the 3 central ones.
05-22-2016, 02:53 AM   #48
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I don't know, as I haven't used that particular lens. On ultra wide angles, I tend to avoid use of auto focus though and use live view to focus for landscape photography or, with the DA 15 just set it at hyperfocal focus point and shoot with it that way.

My guess is that it is a lens issue and not a body issue, as I have had no issues with multiple different lenses on the K-1 with auto focus, but I haven't used the 15-30 yet.
05-22-2016, 03:32 AM   #49
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QuoteOriginally posted by Digitalis Quote
we are talking about the Pentax D-FA 15-30mm f/2.8 on the K-1 here - a completely different lens.
I am aware that the bulk of the discussion on the thread so far has been about 15-30. The thread is titled 'K1 Autofocus', and so it seemed relevant to report some experience with a completely different lens (I actually can tell the difference), since there is a lot of interest in the community about K1 autofocus performance in general. I will certainly take the advice of more experienced board members on how to handle this. Since my post is not exactly related to OPs original post, but is related to the topic title and the behavior of K1 autofocus in general, should I have started a separate thread? My observation from other threads is that not every post is specifically related to OPs original post. I will mildly point out that most threads seem veer far more off-topic than this so to be critiqued on adding an entry on a different lens but still on the subject of autofocus seems unusual to me. If I have unknowingly crossed a PF etiquette boundary then my sincere apologies and I will start a separate thread.

To bring some relevance of this tedious post to OPs question, I do have the 15-30mm and have not noticed any focus issues with either the K1 or K3. Per other recommendations, I usually manually set focus point for landscape shots with the 15-30mm.

05-22-2016, 05:15 AM   #50
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QuoteOriginally posted by 2351HD Quote
... Even a slightly miss focused shot at f5.6 at 20m will look not ultimately sharp as it could.
OK. I thought we were trying to figure out a way to get your pictures taken while you are traveling When you get home, you can get the lens replaced or repaired or etc. In the meantime, a picture 'not ultimately sharp' sounds better than what you have been describing :^)
05-22-2016, 06:19 AM   #51
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I've had severe problems with DA12-24 focusing (phase detection with crop sensor cameras), when there is not enough texture differecies in the spot I'm focusing at. Just wondering if this could be the case...
05-22-2016, 08:56 AM   #52
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QuoteOriginally posted by Tan68 Quote
OK. I thought we were trying to figure out a way to get your pictures taken while you are traveling When you get home, you can get the lens replaced or repaired or etc. In the meantime, a picture 'not ultimately sharp' sounds better than what you have been describing :^)
So a bunch of travel photos that aren't really sharp taken with a $5k camera combo is acceptable to you, cool. Not me sorry.
05-22-2016, 09:36 AM   #53
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QuoteOriginally posted by 2351HD Quote
So a bunch of travel photos that aren't really sharp taken with a $5k camera combo is acceptable to you, cool. Not me sorry.
Until you get your gear tested and fixed/exchanged, maybe just use contrast AF in live view? I know it's slower and less comfortable, but at least you're getting sharp shots that way.

05-22-2016, 09:53 AM   #54
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QuoteOriginally posted by FantasticMrFox Quote
Until you get your gear tested and fixed/exchanged, maybe just use contrast AF in live view? I know it's slower and less comfortable, but at least you're getting sharp shots that way.
That's what I am doing and it's working fine.

I am also seeing a little shot to shot inconsistency with sharpness once correctly focused so will also be testing the SR on and off as well.

Can anybody offer advice on what focus distance I should look to test for Fine Focus Adjustment on a 15mm lens? 5m, 10m, infinity?
05-22-2016, 10:04 AM   #55
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QuoteOriginally posted by 2351HD Quote
Can anybody offer advice on what focus distance I should look to test for Fine Focus Adjustment on a 15mm lens? 5m, 10m, infinity?
The rule that I've come across a couple of times states that the distance between the sensor and target should be 25 x focal length, so in your case 37.5 cm. But if your lens shows inconsistent AF at different distances, then you're probably better off trying to adjust it to the distance you are using most frequently.
05-22-2016, 12:49 PM   #56
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QuoteOriginally posted by jatrax Quote
What AF mode are you using? Try single center point, called 'spot'. Press and hold the button marked AF mode then rotate the rear dial.
Ok. I'll try to answer my own question. My experence with my new DFA 24-70 is to get the focus & exposure you want.
1. use AF S
2. Set AF S to spot(center spot)
3. Set AE metering to Spot
4. Link AE to AF
5. Half press Shutter release button with Focus object in center focus point.
6. Re-frame for desired shot.
7. Release shutter.
05-22-2016, 01:44 PM   #57
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QuoteQuote:
The Pentax K-1's full autofocus shutter lag when shooting the same target multiple times was very fast for a pro-level DSLR. The K-1 required only 0.090 second for full AF using the Pentax 55mm f/1.4 SDM DA* lens. Manual focus shutter lag was just a touch faster at 0.087 second. When prefocused, shutter lag dropped only slightly to 0.086 second, which is a little slower than average for a pro DSLR.
Pentax K-1 Review: Initial Test - Performance
05-22-2016, 04:33 PM   #58
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Some good news and some disappointing news in this particular test report.
05-24-2016, 04:07 PM   #59
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QuoteOriginally posted by RockvilleBob Quote
Some good news and some disappointing news in this particular test report.
Do you care to elaborate? The linked article is preview only and was based on a camera with pre-release firmware. Their full review has not yet been published.


Steve
05-24-2016, 04:27 PM   #60
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QuoteOriginally posted by stevebrot Quote
Do you care to elaborate? The linked article is preview only and was based on a camera with pre-release firmware. Their full review has not yet been published.


Steve
Didn't realize it was pre-release firmware but what caught me off guard was:

Buffer clearing was quite slow, taking a glacial 48 seconds to clear a burst of 74 JPEGs, 31 seconds after a max-length burst of RAW files, and 34 seconds after a max-length RAW+JPEG burst, when tested with our 95MB/s SanDisk Extreme Pro UHS-I card. (Unfortunately, the Pentax K-1 is not UHS-II compliant.)


Bottom line, the Pentax K-1's performance was mixed in our tests, ranging from very fast autofocus and single-shot cycle times to sluggish startup, mediocre burst speeds and slow buffer clearing.
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