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10-16-2016, 10:21 AM   #16
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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.

10-16-2016, 10:22 AM   #17
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QuoteOriginally posted by normhead Quote
I wonder if there is a difference in what we are shooting. I'm shooting small fast moving birds close to the camera in AF-s. Tracking is useless to me because I can't track those birds in the viewfinder, they are too close and move too quickly....so my guess is both our experiences are true.
I shoot larger birds like eagles and such on a longer distance, up to about 50-100 meters. I try to fill at least 50% of the viewfinder. Often they fly over my head and that kind of tracking works quite well.
10-16-2016, 10:29 AM   #18
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QuoteOriginally posted by rawr Quote
A tip: make sure you set the metering to Multi-segment. It fully brings the 86k RGB metering sensor online to help with the AF.
I had not thought about the metering selection effecting the AF like that. Do you have a link or source on this? Have you verified that this works?
10-16-2016, 11:02 AM   #19
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QuoteOriginally posted by Winder Quote
I had not thought about the metering selection effecting the AF like that. Do you have a link or source on this? Have you verified that this works?
The metering module is used in conjunction with AF-C to provide Tracking.

Haven't read that you actually need to change the exposure metering mode, though.



10-16-2016, 11:50 AM   #20
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QuoteOriginally posted by clackers Quote
The metering module is used in conjunction with AF-C to provide Tracking.

Haven't read that you actually need to change the exposure metering mode, though.
Yes. I know there is tracking and basic facial recognition features built into the metering. I didn't know the metering mode selection had an effect on these though. I would like to verify it that is true. I use a lo to of spot and center weighted, so if it is true it might explain some of my frustration with the K-1 AF. I have never seen it explained anywhere.
10-16-2016, 12:01 PM   #21
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QuoteOriginally posted by Winder Quote
I use a lo to of spot and center weighted, so if it is true it might explain some of my frustration with the K-1 AF.
Have nothing to do with it. I use spot 99% of the time, and there is no faster Pentax AF out there then the K-1 in combo with any of the new zooms.
10-16-2016, 03:49 PM   #22
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QuoteOriginally posted by Qwntm Quote
Good points. The K5II DEFINITELY has the lens correction and all other processing options OFF, I know this because the review image takes about 10 seconds to load if those things are on, and the processing does slow that camera down considerably. The K3II, as you say, has those things off when using a non pentax lens, but even when I use a Pentax lens, I have those things on because the k3II is fast enough to deal with it and I have never noticed a lag with that camera under any conditions.


The K1 has those things set to on. (Mainly because I expected the K1 to perform at least to the K3II's standard which I am used too.) But the AF lag was there on the first shot, not after a string of even 2 shots, and those processing options tend to slow things down after the shot, not before, right? So it's not even the K1 clearing the buffer from even 1 shot. There was just this hesitation to lock on from a cold start, i.e nothing being processed.

The processing of photos you have already snapped shouldn't affect the autofocus, anyway. (If so, that is a significant issue and something new to Pentax.)
10-16-2016, 04:38 PM   #23
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QuoteOriginally posted by photoptimist Quote
Strange..... My experience so far has found the K-1 to focus much faster and more confidently that the K-5 even on long-throw focus lenses such as the 100/2.8 macro. A few root causes (and related evidence) might be:

1. Some issue with the 24-70 (supported by gabriels comment but not your experience after swapping lenses).
2. Some issue with the settings of all the K-1 AF menu configurations (not hard to do given that the K-1's manual doesn't explain these options well).
3. A strange interaction with high-frequency flicker in the lighting at the wedding's venue (consistent with poor performance at the wedding and great performance at home).


#3 is a distinct possibility. The place was called "The Party Barn," and it was basically a steel building with fluorescent long tube shop lights. There was a large west facing double car garage door that was open and a lot of ambient cloudy light was coming in from the side. But, the failure of the AF was during the processional when the shop lights were pretty much 100% of the available light for AF, and same thing with the later dancing shots.

---------- Post added 10-16-16 at 05:41 PM ----------

QuoteOriginally posted by Tjompen1968 Quote
In Live View: If Electronic Shutter is ON then it is not possible to use flash.

---------- Post added 10-16-16 at 06:32 PM ----------



Well that SOLVES that mystery!! THANKS!!!

---------- Post added 10-16-16 at 05:42 PM ----------

QuoteOriginally posted by biz-engineer Quote
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.




AF assist light was set to "ON." But as you say, I can't remember it actually coming on at all. It really wasn't that dark at the event.

---------- Post added 10-16-16 at 05:47 PM ----------

QuoteOriginally posted by kenspo Quote
.....there is no faster Pentax AF out there then the K-1 in combo with any of the new zooms.




Well that's what I would have expected, but was definitely not my experience under the conditions I shot last night. Like I said, my K3II and K5IIs was significantly faster to acquire focus under the same conditions.


Now at home at 2AM in my office lit by 1 60 watt bulb, the K1 and 24-70 focused on the dark walls instantly and the K3II and K5IIs hunted. It may just have been the weird shop lights at the event. I am not drawing any conclusions, just reporting an anomaly from what I expected vs. what I experienced.

10-16-2016, 05:02 PM - 1 Like   #24
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QuoteOriginally posted by MadMathMind Quote
This is interesting. Is this true in AF-S mode or just AF-C?
Both. Colour (and scene) detection works best when multi-segment metering is enabled. But colour detection in particular is the key to Pentax AF-C tracking working effectively. (Nikon's '3D tracking' AF relies on colour information the same way).

---------- Post added 2016-10-17 at 11:40 AM ----------

QuoteOriginally posted by Winder Quote
I had not thought about the metering selection effecting the AF like that. Do you have a link or source on this? Have you verified that this works?
The info is scattered around a lot of Pentax pages [see below]
K-3II:
Feature 5? PENTAX K-3 II | RICOH IMAGING
645Z:
Feature 2? PENTAX 645Z | RICOH IMAGING
K-1:
Features5 | PENTAX K-1 | RICOH IMAGING

but the gist of it is on the K-1 feature page:

QuoteQuote:
Auto tracking with PENTAX Real-time Scene Analysis System

Supported by the PENTAX Real-time Scene Analysis System, the K-1’s Auto Tracking function accurately detects the subject’s motion based on various factors including color, then keeps pinpoint focus on the subject throughout the imaging process by automatically shifting the in-focus point.
So the metering system can help the AF a lot, if the metering mode isn't limited by the user.

I have been looking into the K-1/K-3/645Z metering system recently. I will probably write some notes about it soon. It's quite interesting. For example, the metering coverage is not 100% of the frame, and metering coverage varies from K-1 to K-3 to 645Z. But Pentax has never documented this.
10-17-2016, 07:43 AM   #25
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QuoteOriginally posted by rawr Quote
So the metering system can help the AF a lot, if the metering mode isn't limited by the user.
I have been looking into the K-1/K-3/645Z metering system recently. I will probably write some notes about it soon. It's quite interesting. For example, the metering coverage is not 100% of the frame, and metering coverage varies from K-1 to K-3 to 645Z. But Pentax has never documented this.
So how can you test for this?
10-17-2016, 10:45 AM   #26
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QuoteOriginally posted by rawr Quote
So the metering system can help the AF a lot, if the metering mode isn't limited by the user.
Well, on the K1, it seems that the exposure sensor is used in Auto-mode, but not in other modes. So, the choice is too limited (by software), I'd prefer to be able to enable or disable the scene analysis in other modes such as Av,Tv,Sv,TAv,M etc..
10-17-2016, 11:05 AM - 2 Likes   #27
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QuoteOriginally posted by Winder Quote
So how can you test for this?
All the metering data is there in the K-1/K-3/645Z EXIF. Abundantly so.

That EXIF data lets you reconstruct with a great deal of precision exactly what the K-1 metering sensor sees, like so:



And the above represents only about 20% of the data the Pentax RGB sensor records.

Last edited by rawr; 10-17-2016 at 11:15 AM.
10-17-2016, 11:21 AM   #28
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QuoteOriginally posted by biz-engineer Quote
Well, on the K1, it seems that the exposure sensor is used in Auto-mode, but not in other modes. So, the choice is too limited (by software), I'd prefer to be able to enable or disable the scene analysis in other modes such as Av,Tv,Sv,TAv,M etc..


Or hardware. The K1 might not have the processing power to deal with it in other modes. Canon throws x2 processors in their high end machines to keep up with everything on, all the time.
10-17-2016, 11:28 AM   #29
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QuoteOriginally posted by biz-engineer Quote
it seems that the exposure sensor is used in Auto-mode, but not in other modes
The recorded data strongly suggests that the metering sensor is active in all other shooting modes as an exposure meter. But I am not sure what controls all of the work the metering sensor does with other camera systems - like the scene analysis database/system, the 'Deep Learning' scene algorithms, or all the elements of auto-focus. Maybe sometimes the metering sensor only 'helps out' when ordered to by a specific shooting mode like 'Auto'. But I don't think all of it's capabilities are restricted to just the 'Auto' mode.
10-17-2016, 11:49 AM - 1 Like   #30
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I think I figured out the AF delay.


I had the K1 set to "Auto Power Off: 1 Minute." Which usually is no big deal because when you are using the camera it usually stays on while you are using it. But at a wedding there are times when you stand around for 5 minutes or more without touching the camera between shots. If the camera "Auto's Off" it there is a delay while it is restarting and the AF has a lag time. If the camera is awake, the AF is pretty much instant even in dim light.


So next wedding, Auto Power Off will be set to "Off" and we'll see how we go.


This might also account for the poster who said his birding shots had slow AF. If your waiting around for the birds to show up, the camera could power off.


I'm still testing all this but it seems to be the reason for my issue so far...
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