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07-12-2012, 10:28 PM   #31
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I guess to me, everything but 100 and 200 seems over-exposed a bit. My walls are brown and both snowboards have very dark colors. The slight edge of the door you see is white, but has grooves, which you can see at iso 100, but they get blown out everywhere else.
For the second set, it definitely looks like I approached its limits(margin for the 360 minimum flash output). Even at 12800 it is underexposed by a good margin, but can still produce a recognizable photo without the flash. But again all but maybe 100ISO one seem overexposed to me.

07-16-2012, 06:18 AM   #32
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QuoteOriginally posted by top-quark Quote
If you're getting blown out photographs no matter how you shoot, you likely have a faulty flash unit - it does not seem to be a camera firmware issue.
No! Because you put the same flash on a K-x / K20D / K-7 / any Pentax camera before K-5 and with exactly the same settings and setup you get correct exposure. Only on the K-5 you get (sometimes massive) overexposure. This was discussed to death with lots of examples 1 - 1.5 years ago in several threads. Pentax even acknowledged the issue, but never fixed it entirely.
07-16-2012, 09:23 AM   #33
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QuoteOriginally posted by simico Quote
No! Because you put the same flash on a K-x / K20D / K-7 / any Pentax camera before K-5 and with exactly the same settings and setup you get correct exposure. Only on the K-5 you get (sometimes massive) overexposure. This was discussed to death with lots of examples 1 - 1.5 years ago in several threads. Pentax even acknowledged the issue, but never fixed it entirely.
I respectfully disagree: for all those bounce photographs above, I was using K-5, firmware 1.13 and a Pentax-branded flash. This caused no problems whatsoever. I had to really try to get a lousy exposure. There may have been a firmware issue 1 - 1.5 years ago but this would appear to have been fixed.

If you are using the same setup, using bounce flash with your subject roughly at camera level and get blown out images, I do not believe the issue lies with the camera body.
07-16-2012, 10:04 AM   #34
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I am very much enjoying this helpful discussion. Just tried with yet another set of batteries. It is still the case I get some overexposures, but I am finally working out when this happens. I have been shooting in M - I agree that TAv is a no-no with the flash. K5 and AF360 here.

Seems to me that here, aside from some operator errors, my overexposures are largely resulting from minimum flash power limit. In short, I suspect that in bounce the flash always fires with a certain minimum power. This value is a lot higher than the 'real' achievable minimum flash output in direct. The minimum power of the flash when used in bounce is far too high for many situations I have been testing here (i.e. combinations of white subjects and wide apertures), and this limits the flexibility of the flash a little. Flash compensation can be used very effectively to reduce overexposures if this issue is experienced (while using bounce).

With the flash used direct (non-bounce), in this case a far smaller minimum flash power is allowed by the flash. it still is subject to a minimum power, so too near, or too high ISO/large aperture and you can still get overexposures. But this minimum flash level is smaller than that used in bounce, so it is simply is a lot harder to provoke an overexposure in direct.

Seems ridiculous to me that I have scenes here that expose perfectly in direct flash, but overexpose in bounce - but there you have it! Slowly getting more confident about what to do when it happens - -1.5 FEC fixes almost all the problems if experienced, I have found.


Last edited by johnc; 07-16-2012 at 10:20 AM.
07-16-2012, 10:32 AM   #35
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QuoteOriginally posted by top-quark Quote
I respectfully disagree: for all those bounce photographs above, I was using K-5, firmware 1.13 and a Pentax-branded flash. This caused no problems whatsoever. I had to really try to get a lousy exposure. There may have been a firmware issue 1 - 1.5 years ago but this would appear to have been fixed.

If you are using the same setup, using bounce flash with your subject roughly at camera level and get blown out images, I do not believe the issue lies with the camera body.
This is possibly too sweeping. It does not take into account third-party flashes and a lot of people are using Metz models. It is quite conceivable that Pentax fixed issues with their own flashes but didn't test (or care) to see whether third-party flashes still over-exposed.

I used to own a Metz 36 AF-5 and I was damned if I could get a decent exposure without applying negative flash exposure compensation. However, I was also using firmware 1.03 at the time and no longer have the flash to test it. If there is an issue with Metz flashes, for example, you can only go manual on the higher-end models which would make the low end models (like my old 36) less than useful.

I know that Sigma periodically supply firmware updates for their flash units to maintain body compatibility.

Any Metz / Sigma flash users want to post washed-out examples? To keep the variables down, your K-5 body should have firmware 1.12 or 1.13. Ideally, flash should be bounced straight up with a reasonable subject distance. Any Pentax flash users care to do the same?

If over-exposure can be consistently fixed with a certain exposure compensation that, too, is useful knowledge.
07-16-2012, 12:25 PM   #36
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Top-quark, I just tried some more tests, pretty sure that the observations I noted above are pretty close to the mark. You make one very good point here regarding reasonable distance to subject. My k5 (1.13) with bounced AF360 is prone to overexposure at close quarters, under the combinations I mentioned before. I am not really sure why this should be (when pointing the flash straight up, for example), but I think it still supports my observation that the minimum bounce flash power is too strong for some combinations of range/aperture/ISO.

I can easily post a picture of a vertical bounced flash shot with a white overexposed subject taken at f2.8 from 1m at ISO 400. But because either -1.5ev FEC, a lower ISO, a longer focal length (more distance), direct flash (even with diffuser) or faster exposure time (using HSS) all fix the problem, it might be easier to simply conclude that it is worth bearing in mind that the bounce flash power is too strong in certain situations, and can easily be dealt with using a range of different options if any issues are encountered?
07-16-2012, 05:46 PM   #37
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QuoteOriginally posted by top-quark Quote
I respectfully disagree: for all those bounce photographs above, I was using K-5, firmware 1.13 and a Pentax-branded flash. This caused no problems whatsoever. I had to really try to get a lousy exposure. There may have been a firmware issue 1 - 1.5 years ago but this would appear to have been fixed.

If you are using the same setup, using bounce flash with your subject roughly at camera level and get blown out images, I do not believe the issue lies with the camera body.
Maybe there was a firmware issue that got fixed. But there is certainly another problem that has NOT been fixed.

I'm with simico 100% on this. There remains a problem with bounce flash on at least some K-5's.

I have swapped lenses (Sigma to Pentax). I have swapped flash units (Pentax to Metz). I have tried to recreate the same scenario on a different camera (K-x). In all of these cases, the K-5 yielded blown-out bounce flash results, but the K-x was fine. The K-5 was fine with direct flash. The K-5 was fine with bounced wireless flash.

It's beyond doubt, to me, that there's a problem with my K-5 on-camera bounced flash.

QuoteOriginally posted by johnc:
I think it still supports my observation that the minimum bounce flash power is too strong for some combinations of range/aperture/ISO.
That statement is basically equivalent to saying "P-TTL on the K-5 is broken for on-camera bounce flash."

Why would there be a minimum bounce flash power? There's no problem with direct flash, and P-TTL should work the same way in both scenarios:

(1) meter the exposure with ambient light
(2) meter the exposure with a preflash
(3) based on (1) and (2), calculate the flash necessary to bring the exposure up to the desired level
(4) fire!

This should be true irrespective of the direction the flash head is pointing.

Maybe some people are lucky enough not to have this problem. Maybe some people are overlooking it.

But it's there.
07-16-2012, 11:57 PM   #38
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To be honest I do agree! Just making the point that (for me at least) the issue does not occur under all circumstances, and can be compensated. But should I have to? No. There's no reason this should not work better. Works fine in wireless and direct - but on camera bounce has an issue that causes problems in certain situations where it shouldn't. Very frustrating, and I would love to know if the K5+AF540 is affected. Though whether I'm happy to spend more to work around this issue, I'm not so sure.

07-17-2012, 12:04 AM   #39
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This discussion has been made previously, around the time of the K-5 release, and to me there has been no change. I still require -2.0 FEC on all my bounce flash shots on the hotshoe, but not for wireless flash shots. It's a quirk you either live with or complain/give up on. Pentax support denies any such phenomenon. See the previous thread for more details.
07-17-2012, 01:13 AM   #40
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QuoteOriginally posted by top-quark Quote
I respectfully disagree: for all those bounce photographs above, I was using K-5, firmware 1.13 and a Pentax-branded flash.
Uhm... your response has nothing to do with my statement.
You wrote: "If you're getting blown out photographs no matter how you shoot, you likely have a faulty flash unit - it does not seem to be a camera firmware issue." That simply isn't true, because a faulty flash wouldn't give perfect results on any other Pentax camera. If you keep everything the same in a controlled test and only change the cameras, and the issue only happens with one camera (K-5) then it's bloody obvious that the camera (K-5) is the problem.

Just because you don't get the issue (or you believe you don't get it) doesn't mean that the issue doesn't exist. You know, hw and sw errors don't always affect 100% of the customers in 100% of the cases.

Many of us bought the K-5 right when it hit the market (I bought it in November 2010) and discussed this issue many time in many threads since then. Please do a search and read those. One firmware claimed to fix a flash overexposure issue, but it didn't fix it entirely or maybe it fixed a different issue.

I'm using the latest fw, subjects are several meters away, in a 25 square metre room, f4 1/125 ISO200-400 and I have to set from -1 to -2 FEC with hot-shoe mounted bounced flash to get acceptable exposures (and even then I usually have to lower exposure a bit in PP). Unfortunately even the needed negative compensation varies a bit, sometimes -1, other times -1.7, sometimes even -2 to avoid completely overexposed image - sometimes even when shooting the same object in the same scene under same conditions! This is really pronounced with bright(er) objects and scenes, e.g. white shirts, light walls, etc. Normally the metering should make those slightly underexposed, but it seems the K-5 does the opposite. If I turn the flash head to 0 degree (direct flash) or take the flash off the hot-shoe (use it as wireless slave) then suddenly 0 FEC is needed for perfect exposures (though sometimes wireless mode seems to slightly underexpose). I even tested this on static objects with camera fixed on tripod and keeping everything the same, just moved flash head from 0 to 45 and then to 90 degree. Clearly something is broken in K-5's flash metering or other flash/P-TTL related function.
07-17-2012, 05:45 AM   #41
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Very interested to hear if AF540's are the same. I'm really missing the ability to swivel the flash vertical from a portrait orientation here - but am loathe to buy two flashes both requiring FEC using on body bounce. Anyone tried both? May try to get a loan from somewhere.

Last edited by johnc; 07-17-2012 at 06:14 AM.
07-17-2012, 08:11 AM   #42
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Hi Gang....

I had this issue in a big way...so much so I almost sent the camera back..
However, with a little experimenting and double checking on what I had set my K10D and K20D on, I did the same with the the K5 and its solved 90% of the over exposures, the other 10% is me :/

In the menu, go to the last set of pages under the orange "C"
on number 5. AE-L with AF Locked (set to mode 2) and 6. Link AE to AF Point (set to mode 2)
I've also set number 2. Sensitivity Steps to mode 2 as well......

This has helped me massively, as I used to have way too many over exposures whilst doing weddings...I was having to auto bracket loads, to wasting card space.
Hope this helps.
07-17-2012, 02:34 PM   #43
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Hello - Just checking in to say I managed to try Dunc's suggestions, it didn't affect my case (perhaps because I am in Manual mode already?).

I also got to try out an AF540 with my K5 - nice flash, a decent step up from the AF360! But the problem I am having is the same as with the AF360 under the circumstances I describe - the camera is selecting a bounce flash discharge power in certain cases that is too much for the chosen range/ISO and aperture - and this results in overexposures. The problem does not occur in direct, and can be fixed with -2(approx) FEC.

One thing I have noticed today is that the problem is absolutely very much worse with some lenses than others. With my DA*16-50 the results are the worst (especially at the wide end with open aperture), DA*50-135 can also be provoked if pushed hard. I simply can't provoke a problem with my FA 100 Macro, and I have to work hard (e.g. unusual scenes with smaller areas of white pointing directly at the area where the bounce hits) to get a bad result from my A50 f1.2, even at f1.2. I could see with the f1.2 that the bounce is firing with a far lower power than ever will be reached with my 16-50, even at the same 50mm/f2.8.

So basically, while P-TTL and bounce works well under almost all conditions and lens choices, on certain lenses it seems I need to be a bit more careful. I have read it suspected here before that this problem is especially notable with SDM lenses, anyone else having problems might like to check whether all their lenses are affected.... I am not sure we reached the answer here yet, but I seem to be closing down on my problematic circumstances, and the workarounds that I can apply. So I have learned a lot from the discussion

Last edited by johnc; 07-17-2012 at 02:43 PM.
07-17-2012, 05:13 PM   #44
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QuoteOriginally posted by johnc Quote
Hello - Just checking in to say I managed to try Dunc's suggestions, it didn't affect my case (perhaps because I am in Manual mode already?).
Ah....I only use manual when doing studio work....
using the other modes I find it works....would be interesting to see how it works in P mode for you....I sometime use this in weddings due to snap shooting and so no time in setting the exposure myself....
And when in P mode I manually change the aperture, so technically its in Aperture priority..
07-28-2012, 07:42 AM   #45
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In my opinion the problem is related to a wrong (or not accurate) communication of focus point distance from the camera to the flash (in direct light).
Please check differences in exposition when you change focus distance (in manual mode).
At small focal length, there is more approximation in distance evaluation --> more overexposition.

Moreover, when the light is bounced on a wall, the exposition is correct enough (it do not use focal length).

Another think is related to the flash power. 50 is a very big power for very close distance.
If you have a look on Flash manual, Metz says:

"The subject ought to be in the area of approximately 40% to 70% of the value
displayed. This will give the automatic exposure control sufficient scope for compensation. To avoid overexposure, the minimum distance should be no less than
10% of the indicated value! Adjustment to the photographic situation at hand can
be achieved by, for example, changing the aperture of the setting on the lens"
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