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09-28-2017, 09:10 AM   #1
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K1 Focus issues

Hi,
I have had a suspicion for some time that my K1 has focus issues; pictures are sharp once the camera finds focus, but in moderately low contrast or darker situations, typically in the studio, it is hunting for ages, and sometimes just giving up. To the point where I am having to turn lights on all over the studio just to find focus, while everyone elses camera is snapping on first time. I thought it was maybe just pentax, but I have just dug out my old K5, and tested it alongside my K1, and the K5 is streets ahead, locking onto smooth black surfaces almost instantly even in the relative dark. The difference between the two seems to be that the K1 is very reluctant to use the green AF assist light; when it does choose to use it there is a difference, but in many cases where the K5 goes straight for the AF assist option, the K1 tries without, fails, and gives up. Any ideas? I'm running v1.42, and have tried with a few lenses on each camera, same story.
many thanks
A

09-28-2017, 10:04 AM   #2
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I have had similar problems. Did you calibrate your lenses? I can also recommend using the 9 point focus rather than single point. Live view focus should also be more accurate. Other than that, maybe send your camera to Pentax and see if they can fix it...
09-28-2017, 10:21 AM   #3
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QuoteOriginally posted by Dericali Quote
I have had similar problems. Did you calibrate your lenses? I can also recommend using the 9 point focus rather than single point. Live view focus should also be more accurate. Other than that, maybe send your camera to Pentax and see if they can fix it...
Hi Dericali, thanks but I don't think those are the issues, lenses are not front or back focusing, so shouldn't need calibrating. I need to use single point for focussing on eyes, and the K5 manages perfectly well with a single point. Live view: again the problem is not focus accuracy, but ability to achieve focus in low light. I suspect sending it in to Pentax may have to be the way forward...
09-28-2017, 10:55 AM   #4
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QuoteOriginally posted by alcvet Quote
Hi,
I have had a suspicion for some time that my K1 has focus issues; pictures are sharp once the camera finds focus, but in moderately low contrast or darker situations, typically in the studio, it is hunting for ages, and sometimes just giving up. To the point where I am having to turn lights on all over the studio just to find focus, while everyone elses camera is snapping on first time. I thought it was maybe just pentax, but I have just dug out my old K5, and tested it alongside my K1, and the K5 is streets ahead, locking onto smooth black surfaces almost instantly even in the relative dark. The difference between the two seems to be that the K1 is very reluctant to use the green AF assist light; when it does choose to use it there is a difference, but in many cases where the K5 goes straight for the AF assist option, the K1 tries without, fails, and gives up. Any ideas? I'm running v1.42, and have tried with a few lenses on each camera, same story.
many thanks
A
Sounds like a hardware problem. I would send in the camera. No issues in live view?


Adam
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09-28-2017, 01:24 PM   #5
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QuoteOriginally posted by Adam Quote
Sounds like a hardware problem. I would send in the camera. No issues in live view?
Don't think there's a problem in live view, although to be fair I hardly ever use it. Found this on another forum about focus issues which sounds like it hits the nail on the head, based on this not sure sending the camera in will do any good...

"Originally posted by biz-engineer
You've got to switch On the AF assist light. And on the K1, there is IMO a little bug in firmware regarding the light meter threshold used to switch On the assist light: there is a gap which does not exist on the K3 and K5II series. i.e on the K1, the AF assist light switches on when light levels are already too low for proper AF operation, and so there is a range of light level within which K1 fails to focus and when the light level goes down K1 is again able to focus... That's at least what I characterized after seeing several users complaining about low light AF. I believe it can be fixed in firmware... if Ricoh want to do it.


Read more at: https://www.pentaxforums.com/forums/190-pentax-k-1/331889-k1-af-issues-wedding-10.html#ixzz4u0V8oBu3"
10-02-2017, 03:37 AM   #6
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Out of curiosity, how dark was 'darker'? I had this problem in basically dim day light, e.g. overcast afternoon at about 4pm, in a room with large glass french doors.


QuoteOriginally posted by alcvet Quote

I believe it can be fixed in firmware... if Ricoh want to do it.


Read more at: https://www.pentaxforums.com/forums/190-pentax-k-1/331889-k1-af-issues-wedding-10.html#ixzz4u0V8oBu3"
Everyone who owns the K-1 is perpetually hoping/dreaming that all the AF issues can be solved via Firmware, if only Ricoh 'wanted' to do it. I am suspicious of this notion
10-03-2017, 05:07 AM   #7
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i've achieved focus lock in near total darkness with fast lenses(f1.4-f2.8 close subject though) with the k-1 (af light off... hate that thing, can't they use IR light?!?)... what lenses are you using?
10-03-2017, 07:47 AM   #8
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Remember to use AF-S, not AF-C.



10-03-2017, 12:39 PM   #9
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QuoteOriginally posted by alcvet Quote
in moderately low contrast or darker situations, typically in the studio, it is hunting for ages, and sometimes just giving up. To the point where I am having to turn lights on all over the studio just to find focus, while everyone elses camera is snapping on first time.
Strange. I can't recall having any problem with the K-1 managing to grab focus in low-light. Works much better than any of my other cameras, even from other brands.

Sounds like a potential lens issue. Note that some lenses are simply darker than others [T-stop], which I have noticed in the past when shooting with some lenses like my Sigma 105 Macro on my K-3. And of course issues like using UV or protection filters on a lens can also both darken a lens and play havoc with contrast, and hence make camera AF suffer. So perhaps test your K-1 AF with brighter [& filterless] lenses before drawing any final conclusions.

QuoteQuote:
I have just dug out my old K5, and tested it alongside my K1, and the K5 is streets ahead, locking onto smooth black surfaces almost instantly even in the relative dark.
Hmmmmmmm ... Compared to my K-5, K-1 low-light focus is so much more confident. Which is not surprising - AF in the K-5 'Classic' is only rated to work down to 0 EV, whereas K-1 AF is specified to work down to -3 EV. The low-light AF of the K-5 used to cause me problems all the time at gigs.

Anyway, shooting smooth black surfaces in low-light is always likely to be problematic in any camera. If your K-5 manages to reliably get focus under such conditions, you have a very special K-5.

Generally worth recalling some of these AF tips [from Nikon]:


Focus-assist light always remains turned off on my cameras, BTW. With cameras from the K-3 onwards, simply not required.
10-03-2017, 08:59 PM   #10
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QuoteOriginally posted by alcvet Quote
I have had a suspicion for some time that my K1 has focus issues; pictures are sharp once the camera finds focus, but in moderately low contrast or darker situations, typically in the studio, it is hunting for ages, and sometimes just giving up. To the point where I am having to turn lights on all over the studio just to find focus, while everyone elses camera is snapping on first time. I thought it was maybe just pentax, but I have just dug out my old K5, and tested it alongside my K1, and the K5 is streets ahead, locking onto smooth black surfaces almost instantly even in the relative dark.
Out of curiosity, did you have similar problems with your K-3II?


Steve
10-04-2017, 12:10 PM   #11
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Isnt it a 2 year warranty? Whenever you bought the camera, its still covered, i'd send it in if you suspect problems...
10-11-2017, 06:33 AM   #12
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Just a reminder, the camera collects a LOT of focus-related data in the image EXIF, including:

- focus range;
- lens focal length
- number of AF points
- AF points selected
- AF points in focus
and lots more.

The camera can even display the AF points used in an image in the playback thumbnail.

IMHO, the discussion of AF here would benefit from more use of such data resources.
10-12-2017, 10:22 AM   #13
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QuoteOriginally posted by Dericali Quote
Out of curiosity, how dark was 'darker'? I had this problem in basically dim day light, e.g. overcast afternoon at about 4pm, in a room with large glass french doors.




Everyone who owns the K-1 is perpetually hoping/dreaming that all the AF issues can be solved via Firmware, if only Ricoh 'wanted' to do it. I am suspicious of this notion
It was in a room lit by the overhead light, so moderate to slightly gloomy... by pointing the K1 into the darkest corner I could force the AF lamp on, which meant that it got focus no problem, but in the main part of the room it just failed (when pointed at a relatively low contrast subject). The K5 by comparison flicked on the AF lamp virtually all the time, and thereby succeeded where the K1 failed.

---------- Post added 10-12-17 at 10:23 AM ----------

QuoteOriginally posted by stevebrot Quote
Out of curiosity, did you have similar problems with your K-3II?


Steve
I don't think so...

---------- Post added 10-12-17 at 10:27 AM ----------

QuoteOriginally posted by rawr Quote


The camera can even display the AF points used in an image in the playback thumbnail.

.
Really, how? Do you mean it shows the focus point overlaid on the image?

---------- Post added 10-12-17 at 10:30 AM ----------

QuoteOriginally posted by D4rknezz Quote
Isnt it a 2 year warranty? Whenever you bought the camera, its still covered, i'd send it in if you suspect problems...
Yes, I just can't quite decide if it truly is a hardware problem, or as Biz-engineer suggests a problem with how the K1 decides when to turn on the AF assist lamp. Reluctant to be without when I suspect they would send it back after a while saying nothing wrong with it... If only more people had them and we could do some side by side tests, it's all very subjective...!
10-12-2017, 10:38 AM   #14
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QuoteOriginally posted by alcvet Quote
Really, how? Do you mean it shows the focus point overlaid on the image?
Unfortunately, no.

But it does display the focus points used alongside an image preview. (In AFS mode, for example).

View via PLAY button > INFO button > Detailed Information Display.
10-12-2017, 10:47 AM   #15
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QuoteOriginally posted by rawr Quote
Unfortunately, no.

But it does display the focus points used alongside an image preview. (In AFS mode, for example).

View via PLAY button > INFO button > Detailed Information Display.
Ah yes thanks I had that bit figured out, I would really like it to show the focus point overlaid on the image, I wonder if there is any software that will allow this, can't some cameras do it in LR?
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