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03-15-2013, 12:22 PM   #106
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Just a few updates: DTSui, regarding the trim pots on the Pentax AF 540 flash, yes indeed I went through that exercise with both of my 540s, a few years ago, using my K20D. A very worthwhile fix; the K20D had consistently underexposed prior to that.

Once I got the new K5II, I did extensive flash testing in all exposure modes, and found as most have, that the 540 consistently overexposed by 1.5 to 2 stops. I then upgraded firmware to v1.02, and the bounce flash problem was fixed! I see that most people found no improvement though. (I wish I'd saved some of these test shots for direct comparison later.)

Before I upgraded to v1.03, I took a couple of test shots for later comparison. I also included the K20D, just for the heck of it. All exposures were at ISO 100, f4.0, 1/125, Manual exposure, AWB, using the FA 43. When using bounce flash, it was pointed straight up. So, I did the upgrade, and found perhaps only the slightest difference in exposures from the previous v1.02 firmware; but in either case, I consider the bounce flash overexposure issue to be resolved. I'm surprised that apparently I'm one of the few people to benefit from the firmware upgrade(s), but I guess I'm thankful to be so fortunate.

K20D:
https://www.pentaxforums.com/forums/attachments/115-pentax-k-5/163567d1363375289-k-5ii-p-ttl-overexposure-tilted-flash-test-analysis-2mgp8848.jpg
https://www.pentaxforums.com/forums/attachments/115-pentax-k-5/163568d1363375289-k-5ii-p-ttl-overexposure-tilted-flash-test-analysis-2mgp8849.jpg

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Last edited by NeverSatisfied; 03-15-2013 at 12:37 PM.
03-15-2013, 12:27 PM   #107
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Next, K5II

K5II, firmware v1.02:
https://www.pentaxforums.com/forums/images/pentaxforums/attach/jpg.gif
https://www.pentaxforums.com/forums/images/pentaxforums/attach/jpg.gif

K5II, firmware v1.03:
https://www.pentaxforums.com/forums/images/pentaxforums/attach/jpg.gif
https://www.pentaxforums.com/forums/images/pentaxforums/attach/jpg.gif

Well, I wish I knew how to post all of the images, (and smaller), with appropriate captions, in one post! Sorry.

When looking at the K20D shots' histograms, both were peaked at the top of the 3rd quarter, pretty consistent, but I must say I don't care for the yellow cast with bounce flash. K5 histograms with direct flash were peaking just a bit less than the top of the 4th quarter (maybe a tad less for v1.03), and with bounce, were peaking just at the top of the 3rd quarter. Hope this (admittedly informal) test may help or be useful as a comparison.
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Last edited by NeverSatisfied; 03-15-2013 at 12:34 PM.
03-15-2013, 12:45 PM   #108
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Is it possible for you to caption each image to understand what we are looking at?
03-15-2013, 05:01 PM   #109
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QuoteOriginally posted by NeverSatisfied Quote
K5II, firmware v1.02:
https://www.pentaxforums.com/forums/images/pentaxforums/attach/jpg.gif
https://www.pentaxforums.com/forums/images/pentaxforums/attach/jpg.gif

K5II, firmware v1.03:
https://www.pentaxforums.com/forums/images/pentaxforums/attach/jpg.gif
https://www.pentaxforums.com/forums/images/pentaxforums/attach/jpg.gif

Well, I wish I knew how to post all of the images, (and smaller), with appropriate captions, in one post! Sorry.

When looking at the K20D shots' histograms, both were peaked at the top of the 3rd quarter, pretty consistent, but I must say I don't care for the yellow cast with bounce flash. K5 histograms with direct flash were peaking just a bit less than the top of the 4th quarter (maybe a tad less for v1.03), and with bounce, were peaking just at the top of the 3rd quarter. Hope this (admittedly informal) test may help or be useful as a comparison.
I understand what your showing as direct and bounce flash. I do hope and am glad to read its fixed in the newest K5 models. I own the original older version.

03-16-2013, 12:59 AM   #110
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QuoteOriginally posted by NeverSatisfied Quote
K5II, firmware v1.02:
https://www.pentaxforums.com/forums/images/pentaxforums/attach/jpg.gif
https://www.pentaxforums.com/forums/images/pentaxforums/attach/jpg.gif

K5II, firmware v1.03:
https://www.pentaxforums.com/forums/images/pentaxforums/attach/jpg.gif
https://www.pentaxforums.com/forums/images/pentaxforums/attach/jpg.gif

Well, I wish I knew how to post all of the images, (and smaller), with appropriate captions, in one post! Sorry.

When looking at the K20D shots' histograms, both were peaked at the top of the 3rd quarter, pretty consistent, but I must say I don't care for the yellow cast with bounce flash. K5 histograms with direct flash were peaking just a bit less than the top of the 4th quarter (maybe a tad less for v1.03), and with bounce, were peaking just at the top of the 3rd quarter. Hope this (admittedly informal) test may help or be useful as a comparison.
Thanks for sharing Paul.
The 1.02 vs 1.03 results look pretty similar to me, but never mind that.

The problem with your test is that you actually tilted the flash up to the ceiling. This is of course good photography practice, but bad for the controlled test, aiming to compare apples to apples with regard to P-TTL metering. I don't know the characteristics of your ceiling - it might be high, angled, or have low reflectivity. It could very well be that, in combination with the low ISO you used, this was enough to make the shot underexposed, regardless of the existence or non-existence of the bug we're trying to diagnose. The idea is to have the shooting conditions as similar as possible between the shots (including lighting direction), so that the differences in metering can be isolated.

I will greatly appreciate it if you repeat the test, but this time tilt the flash only slightly - so that it essentially still fires forward, but enough to make the flash "think" it is no longer straight-on (there should be some indication of that on the flash LCD - a tilt icon and/or disappearing of the distance scale). This will eliminate the additional unknown variables introduced by changing the flash direction and lighting through the ceiling.

Also, repeat the test with higher ISO and/or wider apertures, in order to take it out of the "comfort zone" where low sensitivity helps avoid overexposure, regardless of metering accuracy. When shooting at a higher sensitivity, the purpose of the first test shot (straight-on) is to indicate that the flash can still meter and fire at a low enough power so that the image does net get overexposed.
Then, if the first shot is indeed OK, then there shouldn't be a reason why the second shot gets overexposed (or, more generally, exposed differently) despite the choice of sensitivity and aperture. If there is a significant difference, then this indicates a bug which results in inconsistent metering.
03-16-2013, 07:07 AM   #111
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QuoteOriginally posted by Noam Quote
Thanks for sharing Paul.
...

I will greatly appreciate it if you repeat the test, but this time tilt the flash only slightly - so that it essentially still fires forward, but enough to make the flash "think" it is no longer straight-on (there should be some indication of that on the flash LCD - a tilt icon and/or disappearing of the distance scale). This will eliminate the additional unknown variables introduced by changing the flash direction and lighting through the ceiling.

...
Perhaps the 540FGZ is different but the 360FGZ doesn't have a setting for tilting the flash "only slightly". The settings are -10˚, 0˚ (forward), 45˚, 60˚, 75˚, and 90˚ (vertical).
03-16-2013, 07:20 AM   #112
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Hi JinDesu,
I wish I knew how to properly caption, or place, the photos within the text. I've seen others' examples where they'll have several photos separated by text and descriptions, and all within the same post. I haven't figured that out yet. But anyway, the first post was of course using the K20D, top photo with flash forward, bottom with flash bounced. The next post is: top photo, flash forward with K5II firmware 1.02; second photo, bounce flash with K5II firmware 1.02; third photo is flash forward with K5II firmware 1.03; last (fourth) photo is bounce flash with K5II firmware 1.03.

James, I can try to do more controlled testing, probably this weekend. However I can only demonstrate firmware version 1.03 from this point on! I assure you though, that I had taken very similar shots before any firmware upgrade, and the overexposure with bounce flash was quite significant. So to me the improvement now is easily noticeable. I'll see what I can do to clarify the situation though. Sorry if my little test series wasn't too well thought-out.
03-16-2013, 12:20 PM - 1 Like   #113
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QuoteOriginally posted by Noam Quote
Here is my methodology (abridged, please see previous posts for more details). I will appreciate it if you try it:
Use mode X in the camera, with the flash set to P-TTL, no compensation. Take one shot of something at a reasonable distance with the flash pointed straight ahead. Take another shot of the same object, this time with the flash slightly tilted (enough to make the flash think it is tilted, showing the appropriate tilt indicator on the UI). Compare the shots.
OK, now have had time for some controlled tests, as per Noam's method above. Gear is K5 IIs (FW 1.03) with AF540FGZ. Settings are X mode, f 5.6, ISO 200, no compensation - well within the flash "comfort zone" in these conditions. Pics posted below in order are:

1. Direct flash;
2. Slight tilt, but not enough to activate tilt indicator on flash rear LCD - distance scale still visible;
3. Tiny bit more tilt, not yet up to 45 degree setting but enough to activate tilt indicator in flash LCD, distance scale not showing (in this position, flash "thinks" it is bouncing, but it is actually still direct flash.
4. Proper tilt at 45 degrees, bouncing off low, flat, plain white ceiling.

Results: Pics 1 and 2 are similar (slightly overexposed for my taste, but the main point is that they are similar). Pic 3 is 1-2 stops overexposed. This is when flash is actually direct, but firmware thinks it is bouncing. Pic 4 is properly exposed, best of them all.

So the misbehavior for condition 3 is still there in FW 1.03 - there is still 1-2 stops overexposure that activates at the point where the tilting mechanism activates the flash tilt sensor - where the flash "thinks" it is tilted for bounce flash, but it is actually providing direct flash light.
But significantly different to what happened with my old K5, and with the K5 IIs with older firmware, the actual bounced flash pics are now properly exposed. To achieve this before, I always had to use a workaround of dialing in -2 EV for any type of bounced flash.
For real world on-board flash conditions, this is a significant improvement for me, as I (and most people, I suspect) never use the situation of "partial tilt", which is the test condition that reveals some sort of ongoing software glitch. Of course it would be much better if the P-TTL actually did what it is meant to do, and provided correct exposure no matter how far the tilt is set, but at least I am now getting normal bounce flash exposures without worrying about EV compensation.

Condition 1


Condition 2


Condition 3


Condition 4


03-16-2013, 01:29 PM   #114
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BJDavey thank you for your contribution. I couldn't have explained it better myself, (and I also agree with your opinion on results looking slightly overexposed in condition 1 and 2, my camera does the same). My only contention is that firmware version 1.02 had already fixed the issue, at least for me. Sounds crazy, I know, and no one else has reported the same findings. I did not do any testing in "condition 3", but IMO that is not a real-life use anyway. More just a way to reveal the glitch, like you said. But at any rate, I'm glad someone else is getting the same (good!) results now with bounce flash, too. Thanks!
03-19-2013, 01:07 PM   #115
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QuoteOriginally posted by dtsui Quote
I started this discussion back in 2011 writing about my experience and findings with K7 overexposure with bounce PTTL flash. See K5 bounce flash overexposure - mystery solved! MUST READ!: Pentax SLR Talk Forum: Digital Photography Review and similar threads. I have since disappeared from all Pentax forums for over a year and I am both surprised and also felt relief to discover more people who own the latest models are also experiencing this issue. This shows the resolute of Ricoh-Pentax to bury its head in the sand to the protest of its customers and a long-suffering Pentax populace. I do not think we as consumers have stood up to our rights and demand Ricoh-Pentax takes firm and prompt actions to resolve this issue and vote with our feet if Pentax fails to bow to pressure. Instead we as a community have chosen to use our ingenuity to develop workarounds and band-aid fixes to solve a problem that rightly belongs to the manufacturer. I cannot imagine Canonians or Nikonians would be so kind and patient if a problem of similar nature or magnitude happen to their equipment.

David
why don't you vote with your feet?
11-12-2013, 03:18 PM   #116
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I recently purchased a Sigma EF-610 DG Super for my K-5 (I) and i'm experiencing the same problems: massive overexposure (2-5EV) when bouncing, direct flash and wireless p-ttl work ok.

But i found a workaround that works for my combination and i think this hasn't been mentioned before:

If you set the Sigma EF-610 to wireless P-TTL slave mode while it's on the hotshoe it will expose correctly! The K-5 will fire the flash on the hotshoe even when it's in wireless mode. So this works without a wireless P-TTL controller, no other flash is needed, not even the pop-up camera flash, just the Sigma EF-610 on the hotshoe in wireless P-TTL slave mode.
02-08-2014, 01:11 PM   #117
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New poster from Iowa weighs in on the K-5 bounce flash problem ...

I'm feeling really guilty but try as I might, I can't get my K-5, AF-360FGZ combination to fail the P-TTL bounce flash tests!!!

I've tried the suggested tests of moving the flash head just around the point where the tilt icon comes up in the LCD display (a difference of probably only 2-3 degrees) and taking one picture just before and a second just after the icon appears. The results of two pictures (pre-tilt icon, post-tilt-icon) can be seen at the bottom and the exposures are virtually identical!

I've also tried a couple of the suggested fixes (using A mode when bouncing and using it in wireless mode even when it's mounted on the camera) and they work too!
Sorry 'bout that (for those of you still having problems).

Some perhaps pertinent information (all from Exif data):

Camera build date: 2012:02:09 (two years ago tomorrow). Firmware version: 1.15.25.27. PentaxVersion: 7.0.0.0.
LensType: smc PENTAX-DA 18-135mm F3.5-5.6 ED AL [IF] DC WR.
Focal Length for pictures: FocalLength35efl 21.0 mm (35 mm equivalent: 31.0 mm).
Other settings: Spot Metering, ISO 400, X Sync.
Flat white ceiling about 5 feet away.
Subjects were about 8-10 feet away.
Both histograms were peaking about in the middle when I used ISO 400. At ISO 100 they were peaking slightly to the left of that (==>underexposed a tad). I didn't use any exposure compensation.

I can't tell you anything about the AF360 build date or firmware since I got the flash used on ebay.

I tried a couple other (perhaps hair-brained) tests that didn't yield any significant results: I tried to "simulate" bounce flash with both the built-in flash and the AF360. For simulation, I tried holding both a piece of white paper and a little mirror in front of the flash heads to (hopefully) reflect the light to the ceiling (otherwise direct mode for the AF360).
I thought this might fake out the flash exposure but all I got was underexposed pictures in the "shadowed" part of the pictures (was lighter at the very top where the flash wasn't blocked).

Final piece of information. I have a program that compares two files (UltraCompare) so I compared the complete EXIF data from the two pictures. I don't know what it all means but it seems like the flash metering data would be significantly different if the overexposure condition existed. But as you can see in the attached file (EXIF_Comparison_Results.txt), in my case they are virtually identical.


Conclusions:

I'm really sorry so many people have problems with the bounce flash but it appears that I'm good with my K-5.
But if they were really interested, it seems like Pentax engineers could tear apart the images and/or the Exif data to get enough data to fix the problem.
Since -- as others have said -- it works in both the wireless and "A" modes, my kneejerk reaction would be that it's a firmware problem. Yet since it works for some and not for others with identical firmware, it seems it must be either a Quality Assurance or a PentaxVersion problem (7.0.0.0 from the Exif data above). If, in fact, it's either of the latter problems, Pentax should either be recalling or replacing defective cameras!

~~~~~~~~~

Since this is the first time I've posted, by way of introduction: I am a long time Pentaxian, having gotten my first "real" camera (the H1a) back in 1968 with money from the first couple of checks from my first "real" job. I also used film Nikons and a couple of starter digital point and shoots before getting a used *stD a couple of years ago. I then got my K-5 (also used) about a year ago. To feed the my inevitable LBA, my lenses to date are the DA 18-55 WR, DA 18-135 WR, DA 55-300 and vintage 50mm f1.4M and f1.4A and a 28mm f2.8.

I'm tempted to get a K-3 but it is too soon for me to shell out additional bucks plus it appears from K-3 threads there might be (different) flash problems with that camera.
So I figure I'll save my money until that settles down, e.g., maybe after 2 or 3 firmware upgrades.

And, oh, by the way, I live in Cedar Rapids Iowa (USA).

If anybody wants any additional info., just ask.
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File Type: txt IMG9845No_Bounce_EXIF.txt (6.3 KB, 78 views)
File Type: txt IMG9846_Barely_Bounce_EXIF.txt (6.2 KB, 67 views)
File Type: txt EXIF_Comparison_Results.txt (7.8 KB, 67 views)
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