[amoringello]

Any one else see this?

I took a multiple exposure today (actually many of them, all with similar results).
This is from a 9 photo multi-eposure and the artifacts get extreme.
Each exposure was about 2-4 seconds.
Pentax K5 with latest firmware 1.03.

The DNG, when read by Adobe is purple, has a few streaks across it, and the lower left has a definite grid pattern. In Aperture or using Mac's built in Preview program, the effect is similar but the color is not quite as bad.

I am assuming Pentax is corrupting the file with multi-exposure. Any ideas?
Can anyone else reproduce this effect?


By the way, I WAS happy to see Pentax made Multi_exposure useful in that you can take all of the exposures in rapid succession and processing occurs afterwards. In prior models, each photo would be processed as it was taken and make the process painful.
At least I was happy until I got home and found this mess.


You can download then DNG file here (17MB) if you want.
The image should be somewhat neutral grey. Certainly nit purple.

http://moringello.com/photo/pentax/MultiExposure9.DNG

http://moringello.com/photo/pentax/MultiExposure9.jpg

[JeffJS]

It's certainly strange. I find it More strange that I do not seem to be able to affect the color cast other than complete de-saturation (with the DNG in ACR CS5). Do they look like that on the camera LCD and does it happen with any other shooting mode? PEF? My camera, with 1.03 does not behave like this btw.

It looks like you've lost a color channel somewhere.

Edit: Did you see this?

https://www.pentaxforums.com/forums/pentax-k-5-forum/137387-message-camera-store.html

[amoringello]

No, camera LCD looked just fine.
Yeah, if you put it into LightRoom, it tries to adjust as far as it can and pegs the tone adjustments but just can't do it. You're probably right with the color channel missing.

I did have Exposure Compensation menu item checked. Perhaps their algorithm is a mess?
I'll have to play with PEF and turning off the exposure compensation... but without that, most images will just turn burned out.

Thanks for the link.

Luckily, everything else is just perfect (well, one *minor* sensor stain that I can live with).


I'm disturbed to hear you cannot reproduce. That means my camera is likely a duff one. ergh!
Of course I dont seem to have the F/BF low light issue, or cannot reproduce, so it might be another intermittent QC issue?

I'll forward this to Pentax. Maybe they have some comment.???
Yeah, who wants to start a pool on what they'll have to say about it? :-)

I'll probably send the unit in for repair at some point, but I will wait until the flood of sensor stain repairs goes down and I can get my camera back in less than four months. argh...

Thanks

[amoringello]

he, he, OK, if you haven't already, try using the Pentax Camera profile now included with Camera Raw.

If I set LightRoom's calibration panel to use Adobe Standard, the color is just fine.
It still has purple streaks near the bottom, but cannot reproduce those at the moment.

The Pentax profile works fine for single exposures.

In fact, profiles I have created using XRite's Color Checker Passport software are also giving the very odd results.

So it seems Pentax is munging something in its RAW file, and Adobe cannot properly handle that with custom profiles.

He, he, who wants to bet I get ANY service from Adobe on this one!
Looks like a good start to a finger-pointing war of futility.

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Last edited by amoringello; 03-20-2011 at 08:01 AM.

[JeffJS]

Don't send your camera in thinking you have yet another sensor problem just yet. Perhaps you've discovered another software bug.

I just did 3 multi exposures. One with PEF which reads into ACR fine and in fact, with CS5 ACR, I cannot even select anything But the Adobe profile. I don't know why that is.

A DNG, with EV Comp unchecked, gives a slight tint (See first photo below). A DNG with EV Comp checked gives a stronger tint (second photo). Admittedly, the first might have the same amount if the exposures were actually lined up. Meaning, EV Comp checked probably makes little difference. In both cases, just as with Your DNG, selecting Adobe profile in ACR shows these photos without the tint.

[JeffJS]

Ok.. Correction. There is something wrong with the WB embedding with Multiple Exposures in v1.03 (and perhaps earlier). I still don't know if it is a Pentax issue or an Adobe issue. I rarely use multi exposure so probably would never have seen this for myself.

The above shots as well as the PEF below were taken with Flash WB set, which should amount basically to daylight. If I leave the PEF to As Shot in ACR, it looks fine as far as color goes. Again, I can only select Adobe Profile with this. That is true regardless of exposure mode but a Regular single exposure PEF (and probably DNG) import fine, with WB in proper tact. If I select the actual WB used, and in fact Any WB, in ACR, I get something like that shown below. ACR doesn't seem to have a clue of what to do with whatever WB is.

In all 3 Multi exposure tests here, the resulting JPG looks fine as far as tint and WB are concerned. The second photo below is from the EV Comp on shot above (DNG).

[JeffJS]

I tried to go back to v1.02 FW but can't. The camera won't let me do it. Perhaps someone who has v1.02 or earlier loaded can try this to see if this has always happened (I suspect we would know by now if it had).

[amoringello]

Cool. Thanks a lot for the confirmation!
I've been running into other non-related issues while testing and have started the downward spiral of being a hypochondriac and thinking my camera is having all sorts of issues.... Just needed to take a break, kick some furniture and re-think whats going on. :-) :-) :-)


Yeah, found RAW+JPEG results in perfect JPEG. No big surprised there.

PEF and DNG behave equally.
sRGB and AdobeRGB make no difference.
Adobe Standard profile seems to give decent color

Oddly, only certain colors are affected.
I accidentally erased my test images (bad day) so I'll get some more... but using the color chart, some reds, some blues and some greens are fine. All grays are fine. On the other hand, some of the colors are just nasty.

You may be on the right track with the white balance... I wonder if adjustment values for certain color ranges are being corrupted and thrown way out of whack. If I stretch my guessing at how things work, that seems to correspond slightly with using custom camera profiles.

I'll try other white balance modes once I get done with catching up with housework. ergh! :-)

[amoringello]

I wish my server would allow external images to be inserted, but the following are with the color chart.
I tried shooting with a view white balance settings, no real difference. (it is RAW, so I guess I should not have expected any)

Anyway, some examples with the color chart:

Samples - two photos: Top row - JPG and RAW from single Exposure, bottom row - JPG and RAW from 9 shot multi-exposure.
http://moringello.com/photo/pentax/example.jpg

Original DNG:
http://moringello.com/photo/pentax/_AMP3593.DNG

Original JPG (shot RAW+JPG):
http://moringello.com/photo/pentax/_AMP3593.JPG

DNG with Adobe Standard Profile, set to Cloudy white balance within Light Room. I shot this one with Cloudy White balance in camera.
It seems only the "As Shot" white balance setting makes the image look close to what it should be. The color balance scales are still pegged to the bottom and not quite right.
http://moringello.com/photo/pentax/_AMP3593_cloudy.jpg

Oddly, with Mac OS X preview, more of the colors look good, but this is where some of the colors look fairly correct and odd colors look out of sorts:
http://moringello.com/photo/pentax/MacOSX_Preview.png



Oh yeah, as a final note... I did try other memory cards as well. Just on a wacky outside chance someone might think that the card might be an issue.

[JeffJS]

Oh yeah, as a final note... I did try other memory cards as well. Just on a wacky outside chance someone might think that the card might be an issue.

Now That would be something else... If we both had the same memory card error. That Doesn't rule out the possibility of a write error from multiple exposure however. I think however, we can safely say that the camera sensors and electronics are fine. I would still like to see this from someone still running an earlier firmware.

By the way, What was your original photo supposed to be? I saw a small tree limb and what looked like a rock. Water?

[amoringello]

Yep. The falls here are running very high, so what is normally a ten or thirty foot waterfall is now a relative;y small stone and tree branch sticking out through the river. I wanted a really long (20-30 second) exposure to excessively blur the rapids, but only had five stops of ND grads and could only get down to a 3 second exposure.
Multi-exposure worked pretty well to simulate a longer exposure -- the nine overlapped images did a lot to blur repeating patterns and texture on the shorter exposures.

FYI, if interested in what I did and didn't want...

http://www.flickr.com/photos/amoringello/5542898276/in/photostream
http://www.flickr.com/photos/amoringello/5541602770/in/photostream/

[JeffJS]

Interesting. I would have never thought of doing it that way..

[amoringello]

I emailed Pentax. They wanted me to send example files.
They also asked I try with the latest update of the Pentax Digital Camera Utility.
And damned if the color wasn't perfect!

BUT... if you stray from the default settings and change the color temperature, for example, the color is just abysmal. I'm assuming quality assurance looked at the resulting image and said "looks great" and left it at that. :-( (assuming QA even checks results from multiple exposure)

So, their move.

At least I don't think they can point fingers and make us wait for Apple and Adobe to make changes in a feature rarely used in a brand that is barely recognized by their companies in the first place.

[JeffJS]

So their answer is to use Their shitty software? If we wanted to do that, why bother with RAW at all?

[amoringello]

That was my first impression as well.
Honestly, it is not a bad methodology to debug the issue. I am hopeful that is the direction they were thinking.

- If their software works fine, then it is likely they would point to Adobe or Apple as being responsible to fix.
- If their software shows a problem, it seems to point to being a Pentax issue.

... and since their program does indicate a problem, we are in a better position to tell them to go shove-it and fix their firmware.

I guess we'll see how responsive they are to fixing problems.