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Forum: Pentax K-3 III 08-04-2021, 12:22 AM

Not a good look..
Posted By Svenneke

Replies: 125
Views: 9,379

Hi Kobie, I remember the day very well you and I got deleted from his Youtube channel for our comments on free choice of gear. My opinion was that I don't need a Formula 1 car if I needed a tractor for the job, (in my case my very capable and thrusted K1) do you remember his reaction?

The problem with Li is, I discovered that a few days later in an earlier vodeo from him, that he became very dissapointed at a certain moment in time when he discovered that he hardly got any revenu from his affiliate links for his Pentax reviews.
After that he announced that he would quit making reviews about Pentax gear, ... but he didn't and worse, he did post a lot of very negative biased "reviews" with at times ridiculous arguments. It's very sad that certain reviewers only praise a brand if they think they will get enough money from their reviews.

Before that he was praising Pentax in almost every possible way, so I think that people should be aware of this if they watch his videos.

I hope everything is good with you all.
Greetings from Belgium
Sven

Forum: Product Suggestions and Feedback 02-17-2019, 03:31 AM

Addition to composition adjustment: Scheimpflug with tilt and yaw
Posted By Svenneke

Replies: 11
Views: 1,822

Hi Zapp, Photoptimist is right, only the shift function requires a larger image circle, the tilt function can be done pretty easy within the image circle cone. I want to add and admit that lenses that protrude more into the body (like my 30y old ultra wide Pentax 15mm for example) will increase the chance for getting vignetting in the corners of the sensor that tilt/move in the direction of the lens, because the sensor might reach the end of the image circle cone faster with these lenses because the cone is shorter.
A 35mm and above should not have problems with sensor tilt at all. Besides, the DOF of a 15mm is so high that a tilt function is not needed.

I know that there are limits to tilting the sensor, but being able to rotate the plane of focus to a certain extent would be very handy.
Would it replace the possibilities of a real TS lens? Far from, but having the possibility to change the plane of focus a bit can be of great help in being more creative and also for using more optimum apertures in certain images where one otherwise does have to use apertures that start to cause diffraction.

A real TS lens can go far beyond the limits of tilting the sensor, shure, but the only option at the moment for Pentax users is the Rokinon/Samyang TS 24mm. Maybe users of this lens can provide some help here, but If Pentax would make a TS lens again, it could be a welcome addition to a camera that is so good for landscape and architecture and other technical stuff.

Have a nice day.
Sven

Forum: Product Suggestions and Feedback 12-20-2018, 01:39 AM

Addition to composition adjustment: Scheimpflug with tilt and yaw
Posted By Svenneke

Replies: 11
Views: 1,822

Good morning photoptimist,

That was an excellent explanation of how this technique works! Thank you so much for that!
I understand now that the shift of the sensor (+ the roll) in practice is sufficient enough to compensate for almost all the shake movements that the user can cause, that is awesome info.

So, even the astrotracer function only compensates for the movement of the earth by shifting and rolling the sensor? Now that I think about it, it seems obvious because we have to focus at infinity for the stars to be sharp. If the focus is at infinity, there will be a fixed plane at the sensor where everything will be sharp from corner to corner. Tilting and yawing could even cause less sharpness because the objects remain at infinity, in theory a plane parallel to the lens, but the sensor could move out of focus on both sides (one side inwarts, the other side outwards) if one uses a wide aperture with a relative shallow DOF. Am I correct in thinking this? Or will even wide open the DOF be enough to keep the stars sharp if the sensor would tilt and/or yaw? For example while using a 15mm or another ultra wide lens it would create less problems compared to the 300mm you mentioned? I guess it all depends on the amount of real tilt and yaw the sensor can do?
If pentax will bring such mechanism to a new camera in the future, my respect for the engineers who develope this and to the programmers who must write the code to control this kind of system.

I am always amazed how incredibly good this SRII now already works when I take a look at the display (at 100% zoom) after taking a picture.
0.8" is the longest exposure that I could take without a tripod, only by resting my arm on my elbow. The result was pin-sharp. Isn't it unbelievable that we can use such incredible advanced technology today? I really admire those genius engineers who design such technology.
A long time ago, we all had to think about preventing camera shake and getting more noise with higher ISO films. Nowdays things are so much improved with IBIS and very sensitive low noise sensors, that we hardly have to think about it. We are spoiled by the progress in technology.

Have a great day photoptimist and enjoy the Holidays!
Greetings,
Sven

Forum: Product Suggestions and Feedback 12-19-2018, 03:24 PM

Addition to composition adjustment: Scheimpflug with tilt and yaw
Posted By Svenneke

Replies: 11
Views: 1,822

Hi photoptimist,

Thank you for your thoughts and explanation.
I wonder how the current SR mechanism can compensate for tilt and yaw if the sensor remains in the same plane and the lenses are fixed because they have no image stabilisation?
Is the information on the pentax website not telling us the whole story?
PENTAX K-1
After looking at the illustration on that page, I was under the impression that the sensor did rotate up/down for tilt and left/right for yaw compensations? How do they achieve that without moving the sensor out of the same plane?
If the sensor was fixed in that same plane, would it not only allow for 3-axis stabilisations (up/down shift, left/right shift and roll)?

Thank you in advance for your explanation. I worked with technical cameras in the past so to me it seemed obvious that the sensor would move the same way as the back of such a camera.

Have a good day.
Greetings,
Sven

---------- Post added 12-19-18 at 03:33 PM ----------

Hi Steve,

Thank you for pointing me to that thread, I will certainly look into that.

Indeed the amount of rotation via tilt and yaw, if they would made it possible, would be pretty modest, but nonetheless, it could be very handy for those who know how Scheimpflug works. It is a very powerfull way to optimise your aperture settings and to improve certain photo's. Even for those who don't know how it works, that technique still would make sense if it could be automated to some extend by the camera like photoptimist also suggested.

Nice to read your feedback too Steve.
Have a great day.
Greetings,
Sven

---------- Post added 12-19-18 at 04:22 PM ----------

Hi photoptimist,

Thanks to Steve his link to the older thread, I found your explanation in post #33 how pentax achives the tilt/yaw compensations and that makes sense now to me.
So in reality, the sensor moves only up/down/left/right and rotates along its axis for roll compensations. If I understand it correct, the tilt and yaw is corrected for by moving the sensor the right amount in the same focus plane, parallel with the lenses.

I totally agree with your explanation in that post #33 about how little amount of rotation should only be needed according to the kind of lens you use. A wide angle lens would benefit much more than a tele lens, but still the last one could be used with a more open aperture than without the possibility of using Scheimpflug.
So it seems we really have to wait for the new patented construction that could allow us to use real tilt and yaw movements of the sensor. Great times are coming it seems...

Steve, thank you for the link, I didn't knew that pentax filed that patent and it is great to see them developing that kind of specialized techniques. It shows that pentax is a company that thinks differently and listens to what photographers want to use.

However, there are some limitations. If you only can rotate the sensor and not the lens also, there will be some small amount of perspective distortion visible because for example the plane of a building will no longer be parallel with the sensor plane. It should be possible to compensate for that by rotating the camera slightly by itself.

It also possible that with some wide angle lenses that slightly intrude inside the body, there will be a little bit more vignetting when the sensor is tilted to its maximum amount. But that can easily be corrected afterwards.

OTOH it seems very usefull for creating miniature landscape style images, for those who like that kind of photography.
Architecture photography also could benefit.
Also, using a wide aperture and focussing on two different objects or persons, one near and another somewhat further away, to isolate them from the rest is another great option. It could open a lot of possibilities.

Goodnight everybody.
Greetings,
Sven

Forum: Product Suggestions and Feedback 12-16-2018, 07:53 AM

Addition to composition adjustment: Scheimpflug with tilt and yaw
Posted By Svenneke

Replies: 11
Views: 1,822

Hi everyone,

I am a very happy owner of a K1 and have some ideas about the possibilities of the sensor shake reduction.

Is anybody interested in being able to manually tilt and yaw the sensor, just like with compostion adjustments does with shifting the sensor up/down and left/right?
Like with a technical camera, one could change the tilt and/or yaw angle of the sensor to change the direction of the focus plane. The rules of Scheimpflug could be used this way to be able to use a less high aperture value for landscape and other styles of imaging, to prevent diffraction from using high aperture values.

The way to set these changes could be done in different ways and could be done as follows (of course via LV):

- the camera ask you to choose the first selection point for measuring sharpness, then the second point (camera each time shows a rather small square shape that can be moved via up/down and left/right buttons and hit OK)
- after confirming both points, the camera show both points at the same time at 100% via a split screen
- choose if you want to adjust the tilt and the yaw independently via the front and back dials or...
- choose if you want to be able to set the amount of inclination of the sensor and the direction between 0-360° with the same dials
- set the amout with one or the other method until both 100% zoom are sharp(er), confirm sensor setting with OK
- take image with better back to front sharpness with more open diaphragm values

Of course this method will have the technical limits of what the sensor is capable of tilting/yawing in all directions, but the same applies to composition adjustments and people are happy that this function is already present.

The first method (if you choose tilt and yaw independently is the best choise if you want to have the camera leveled to the horizon and want more sharpness from the foreground to the background or if you want a building for example from left up close to right in the distance and want it to be sharp all the way without needing an aperture of for example 16-22 or higher to get everything sharp enough. It will prevent loss of sharpness due to diffraction.

The second method by setting the amount and turning the angle between 0°+ and -360° is more handy for cases where the focal plane is not in the direction of 90° down/up or left/right, but has a different angle in between. In that case we could be able to change the amount and the angle of tilt/yaw at the same time with both dials while looking at the two 100% zoom split screens that you want to become sharp(er).

If anyone is interested, spread the word.
I hope my explanation is understandable because english isn't my native language.

Have a good day and happy shooting.

Forum: Troubleshooting and Beginner Help 12-11-2018, 06:06 AM

Possible bug in firmware K1 with manual white balance and pixel shift?
Posted By Svenneke

Replies: 47
Views: 3,932

Hi Steve,

As soon as I find some time this week, I'll do the test and will try to extract each of the four images.

With 'problems' like this, I would not be surprised at all Steve if the answer should be something rather simple.
It sometimes only require one single parameter between the whole series of calculations that is wrong or has a range that falls beyond what was required, and the end result could become unexplicable. I often make rather complex Excel files and use Access daily for work and sometimes typing one simple error in a formula can make the whole spreadsheet useless.

One day I had a problem in Access and I could not search for new entries anymore in the database. It took me 2 days to find out what happened. The IT-specialists who are supervising our computer systems couldn't find the answer neither.
I persisted and found out myself that by entering a date in a field and pressing "enter", instead of going to another reference field, the database became corrupted because that "enter" changed another value as well in a reference table that it was not supposed to do. It literally changed a value 'behind the scenes'. In a reference table the 1 in that field caused the database to look at what was given as input by the user and searched the corresponding data.
After the 1 became a 0 the database no longer looked at the data that was asked by the user, but only to the last data that was used before, and continued to do that forever. This caused that I could not search for new entries anymore and was a real PITA.
It took me almost two days to find out that a one in the background was replaced accidentally by a zero, only because of a fault in the way the database was constructed. I changed that zero back to a one, saved the changes and immediately everthing worked again as before.

In the case of the K1 an the weird yellow color under those specific circumstance, I would not be surprised if something similar simple happens.
But of course it also could be something subtle and at the same time very complicated like you suspect.
It would be nice to sit together on the same computer, but unfortunately the distance between us is a little problem ;-).

Have a good day Steve, I'll keep you up to speed if I have found something.
Greetings,
Sven

Forum: Troubleshooting and Beginner Help 12-10-2018, 02:15 PM

Can't complete firmware upgrade
Posted By Svenneke

Replies: 4
Views: 1,140

Hi syslyn,

What I experienced with the first update of the firmware of my K1 was that the camera would not show the card as formatted, and showed no card at all, even after I formatted it already in-camera. So I also could not see the firmware update screen.
The simple solution was that I formatted the sd card in a computer first and inserted it back again, formatted it in-camera again and the camera immediately found the card and could do the upgrade of the firmware.
Maybe this is not your problem with your camera, but I would mention it just in case the good tip from photoptimist would not be enough to solve your problem.
Good luck!
Greetings,
Sven

Forum: Troubleshooting and Beginner Help 12-10-2018, 02:02 PM

Possible bug in firmware K1 with manual white balance and pixel shift?
Posted By Svenneke

Replies: 47
Views: 3,932

Good evening Steve and thank you for your answer.

I was under the impression that demosaicing referred only to the kind of interpolating calculations that must be made between adjacent RED, GREEN and BLUE sensels in that Bayer pattern to build up the image. So, is adding together those four sensels, one RED, two GREENS and one BLUE sensel, with pixel shift also called demosaicing? I did not know that but it make sense since in RT that setting is found in the same place. Thanks for clarifying this.

I understand what you mean that each individual exposure of a pixel shifted image should have the same WB properties. I am pretty sure they have because when I look at every single one of those four images, they all look the same.
What is remarkable is that on Windows 10, when I open such file in the standard viewer, it is also yellow, but not in RT or camera raw. Can you think of what reason this could have? Is Win 10 viewer reading something that the camera is also reading in this case?

I am interested in the test if you could do that.
Greetings,
Sven

Forum: Troubleshooting and Beginner Help 12-09-2018, 08:43 AM

Possible bug in firmware K1 with manual white balance and pixel shift?
Posted By Svenneke

Replies: 47
Views: 3,932

Hello everybody,

To summarize this thread, I think it's safe to conclude that under certain circumstances, meaning, a very warm color temperature near or below the lowest range of 2500K, the rendered image in the K1 can cause a faulty (very yellow) rendered color, but only when using the Manual White Balance in combination with pixel shift.
Photoptimist gave a good and very logical explanation of what possibly could happen in that case.

So I came to the conclusion that purely technical speaking, the difference in rendering between the image without pixel shift and the same with enabled pixel shift, could possibly be called a bug, but...
If this indeed happens outside the specified range that pentax has printed in the manual, 2500K - 10000K, in that case it cannot be blamed on the manufacturer. Can it be solved via a firmware update? Possibly.

As it seems after all the tests I did with the Manual White Balance measuring in-camera, it is possible to even take measurement well below 2500K without and with pixel shift, without a warning from the camera that you are outside the official range.

But to be fair, in reality this is a benefit and not a disadvantage, isn't it?

The good news is that even despite this, the pixel shifted RAW files are equaly usable as the non pixel shifted RAW files once you import them into your RAW editor.
So just be aware that if you take a Manual White Balance measurement in extreme warm WB light conditions, the measurement could end up below 2500K and can be accepted by the camera.
The camera can still take good pictures, but keep in mind that it is possible that you are working outside that official range of the WB without knowing it (2050K in my image).

This is good news, because it means that in real world circumstances the pentax K1 can even measure and use a wider WB range than 2500K - 10000K as it is specified in the properties. Just be aware that in that case, the images with enabled pixel shift can look abnormal in-camera, but are still usable in your RAW editor.

Of course with RAW files we can always set an automatic WB, a Color Balance setting of 2500K or any other WB in-camera and change it later in our RAW editor of choise into whatever we want. This will prevent that the camera measures a WB lower than 2500K.
I could not reproduce the yellow color with other WB settings.

On the other hand, if you need to make jpg's in-camera for whatever reason, it seems wise not to make such extreme low manual WB measurements because the WB would be "baked" into the jpg file, the jpg will or can look very yellow and the file would become unusable. In that case, using RAW is the solution if you need pixel shift, or disable pixel shift and remain in jpg mode is the other option.

Anyway, to me this means that my pentax K1 performs even better than expected under extreme light conditions.
Happy shooting everybody and thank you all for your time and support.

Greetings,
Sven

Forum: Troubleshooting and Beginner Help 12-08-2018, 11:15 AM

Possible bug in firmware K1 with manual white balance and pixel shift?
Posted By Svenneke

Replies: 47
Views: 3,932

Good evening pentageek and thank you for the test so far.

My camera also has 2500K as minimum color temperature setting. But if the light source is even warmer than that, the manual setting by color temperature is not enough. In that case I switch to custom measurements with a white paper.
Be shure to use the Manual White Balance, not Color Temperature in the WB settings options.
With Manual Wite Balance, it seems the camera can go even a bit lower than 2500K, at least if Camera Raw 8.5 is reading the WB correctly. CR 8.5 showed 2050K as WB that the camera had set and the non pixel shifted images were all very fine.

I also like my pentax very much. It is such a solid camera!
Have fun pentageek.
Greetings,
Sven

Forum: Troubleshooting and Beginner Help 12-08-2018, 09:55 AM

Possible bug in firmware K1 with manual white balance and pixel shift?
Posted By Svenneke

Replies: 47
Views: 3,932

Good evening photoptimist and thank you again for this good answer.

I understand pretty well how color temperature works, I've seen all this during my years of educational training as a professional photographer. It is nice to see a good summary written by you above.

To answer about the color temperature, a few minutes ago, I added a little bit of extra info to my post above. The color temperature that is registered in camera raw was 2050K, I figured it out. So you are right by saying that those lights have less blue than they should. Although, the single shots with that setting still where perfectly usable. See my added info above.

I tried something in photoshop in respons to the second part of your post. I shifted the levels of the blue channel in the histogram of a normal exposed and normal colored version. I took the left handler of that blue channel and slided it to more than over the middle and voila, I saw a picture that almost looked exactly like the same yellow color as in the problematic files. It looks like with these extreme manual WB settings, the left side of the blue histogram is completly cut away and the remaining information is pushed into the left corner. You can see that in my picture number 3 of the histogram also.

What you wrote about the blue channel that needs to be multiplied with a large number, as far as I can interprete the histogram, It looks as if the camera 'forget' to multiply the blue channel because all info in that channel is pushed into the left corner and is very small, compared with the green and red channel. That corresponds more or less with what you wrote, I think. Correct me if I'm wrong please.

I like this thread also, it is very nice that people all over the world are connected with the things they are interested in. The pentax K1 is an incredible camera for me and I love every minute working and experimenting with it.

Have a good night.
Greetings,
Sven

---------- Post added 12-08-18 at 10:00 AM ----------

What I forgot to mention is that I opened these files in RT 5.4 and Camera Raw 8.5 and in each program the histograms are perfect and all information looks exactly like the non pixel shifted ones.

Forum: Troubleshooting and Beginner Help 12-08-2018, 07:31 AM

Possible bug in firmware K1 with manual white balance and pixel shift?
Posted By Svenneke

Replies: 47
Views: 3,932

Hello photoptimist, thank you for jumping in.

That is a very interesting explanation. I had a feeling that it should be found in this direction, but I could not explain it as good as you just did. Thank you for that.

As far as if the color temperature with f.lux enabled is very true to life, I don't know, but my test confirms that with a setting of 2300K the non pixel shift can be used without a problem. Maybe the real color temperature is more around 2500K and the camera can still operate fine? Below that value I could not make a measurement anymore, and that is normal regarding the range of the camera as you wrote.

I agree with you that these last tests should show how the WB limits differs between non ps an ps images.
I hope that other pentax K1 users can do the same test.

Thank you all, it is nice to see how people help each other.
Greetings,
Sven

ADDED INFO:
I opened one of those "buggy" dng files in camera raw 8.5 and found out that the WB in-camera after a custom measurement, made with a white paper from the IKEA LED lights set to warm white, was set by the camera at 2050K.
The single picture shot was still fine, but not the pixel shifted one.
This means that the pentax K1 can go pretty far beyond what is stated in their specifications with normal pictures, well below 2500K in this case.

Forum: Troubleshooting and Beginner Help 12-08-2018, 07:01 AM

Possible bug in firmware K1 with manual white balance and pixel shift?
Posted By Svenneke

Replies: 47
Views: 3,932

Hi Not a Number,

The individual pixel shifted images do look as they should look and are all fine. I posted this info some posts earlier.
There is absolutely no visible difference between the four individual images in RawTherapee. RT renders those same 'buggy' images perfect, as well as camera raw 8.5 does, no problems with both programs.

But thanks anyway for your idea.
Greetings,
Sven

Forum: Troubleshooting and Beginner Help 12-08-2018, 06:42 AM

Possible bug in firmware K1 with manual white balance and pixel shift?
Posted By Svenneke

Replies: 47
Views: 3,932

Hi everybody,

I found a way to reproduce the problem. It is not a 100% acurate way, but it works to show what is happening, even without the LED lights.

- I started my computer and already had f.lux installed before.
- Then to set a starting point I changed the color settings in f.lux and set it to 5500K: Sunlight
- I opened notepad and made it big enough to be able to measure on screen the pure white that was emitted.
- I pointed my camera at my screen and made sure that no other light source could be measured while taking a shot for making a custom white balance from my screen, stored it in K1 slot of manual WB
- minimise notepad and open a nice picture with lots of colors full screen
- I made 1 shot without ps and one shot with pixel shift enabled
- made changes in f.lux and set the colors to 4200K, 3400K, 2700K, 2300K and 1900K and made the same two shots after making a new manual WB each time

These are the very interesting results:

5500K ------------ no ps ------------- WB OK ------------ image OK
5500K ----------- with ps ------------ WB OK ------------ image OK

4200K ------------ no ps ------------- WB OK ------------ image OK
4200K ----------- with ps ------------ WB OK ------------ image OK

3400K ------------ no ps ------------- WB OK ------------ image OK
3400K ----------- with ps ------------ WB OK ------------ image OK

2700K ------------ no ps ------------- WB OK ------------ image OK
2700K ----------- with ps ------------ WB OK ------------ YELLOW image

2300K ------------ no ps ------------- WB OK ------------ image OK
2300K ----------- with ps ------------ WB OK ------------ YELLOW image

1900K ------------ no ps --------- WB not possible ---- NO image
1900K ----------- with ps -------- WB not possible ---- NO image

I could not make a more precise test because f.lux does not allow for finer settings, but now we know that the K1 has a rendering problem when the manual measured white balance is somewhere between 1900K+ and -3400K.

It should be pretty easy to recreate the test I just did, please anybody?

Have a nice day and keep me informed about the results.
Greetings,
Sven

Forum: Troubleshooting and Beginner Help 12-08-2018, 01:59 AM

Possible bug in firmware K1 with manual white balance and pixel shift?
Posted By Svenneke

Replies: 47
Views: 3,932

Hi swanlefitte,

I tried it already yesterday evening to find out what the custom WB was of those lights, but haven't found it, yet. I'll try it again later this day and keep you up to speed as soon as I can.

You think exactly what I think regarding the parameters. Some specific and extreme value must set off the reading and causes it to apply a wrong interpretation of the custom WB. Hence the histogram that always shows a blue channel that is pushed completely into the left side. Even the picture I took outside had that same skewed histogram, although the non pixel shifted version shows an obvious blue cast in the image, what is to be expected.

Have a nice day, greetings,
Sven

---------- Post added 12-08-18 at 02:23 AM ----------

I will try setting adobe rgb vs srgb to test if it will make any difference. I will hav to wait till this evening to do the tests because it is daylight now.

Greetings,
Sven

Forum: Troubleshooting and Beginner Help 12-08-2018, 01:02 AM

Possible bug in firmware K1 with manual white balance and pixel shift?
Posted By Svenneke

Replies: 47
Views: 3,932

Wow, good morning and good thinking Swanlefitte, thank you sooo much, you just proved what the culprit is!!!
I did the test as suggested with that custom WB made from the warm white IKEA LED lights indoors and went outside in daylight.
As expected, the WB from indoors caused a very blue image, without pixel shift enabled.
But when I enabled pixel shift with the exact same WB and the same other settings, even now the image looked as yellow as all other problematic ones that I made indoors before.

To make sure that it happens only with a custom WB like this, I tested it also with the WB set to tungsten outdoors, without and with enabled pixel shift, both images were as blue as could be and looked exactly the same.

You proved that my camera goes nuts when I make a custom WB with these specific lights.
As far as I can think, it seems like it is doing something wrong during the number crunching of the four images.
The demosaicing proces from the bayer pattern works perfect with every possible WB setting or mode, but with the pixel shift calculations, no demosaicing is needed then, it looks like the camera applies a faulty calculation with that custom WB.

Thank you so much swanlefitte for pointing me in the right direction, it drove me nuts each time I saw those weird yellow colors. I think, at least with my camera, that this confirms that this realy is a bug in the software.

Greetings and have a nice day,
Sven

---------- Post added 12-08-18 at 01:31 AM ----------

Hi everybody,

Another thing that comes to my mind is this.
While taking these pictures outdoors, I see image 1...2...3...4... appearing on my display, each one has the blue color that was expected. But when I used the custom WB outside, the final rendered image suddenly became yellow.
For the display of the camera to be able to show the four miniatures during the exposure of the shot, the camera must apply the custom WB with each frame while using the demosaicing proces. But when the camera shows 'calculating image' that demosaicing isn't needed anymore because it it rendering the pixel shifted image now, and that is the moment the final image becomes yellow.

I hope someone can test this under the exact same circumstances.
No other light source may be visible, so indoors, cutains closed, dark outside, only these IKEA TRADFRI LED and only set to their warm white setting.
Then make a custom white balance on a white sheet of paper (or a grey card, had the same results) and store it in slot K1, 2 or 3.
Take a picture without pixel shift and after that, enable pixelshift and make sure nothing else changed.
I am curious if somebody can come to the same results, or if it is only my copy of the pentax K1?

Second test, do the same as above, but now with the IKEA light set to neutral or cool white.
Again take a picture without and with pixel shift. This should not cause any problem with the colors.

Thank you in advance.
Enjoy your day.
Greetings,
Sven

Forum: Troubleshooting and Beginner Help 12-07-2018, 04:38 PM

Possible bug in firmware K1 with manual white balance and pixel shift?
Posted By Svenneke

Replies: 47
Views: 3,932

Good evening Steve,

Thank you for your answer and the link to that interesting article.
I am very aware that in reality a spectrogram of a LED light is not that smooth and is very peaky because of the way it's light is emmited via narrow bands in the light spectrum.
One should be able to use a meter like the Sekonic C-700R SPECTROMASTER or other professional meters to see pretty precise how the spectrogram looks like.
(I studied math, science and photography, so I know a few things about light and technic, at least I think so, but I am eager to learn more every day so any link to interesting articles is always very welcome)
Maybe more about this in another topic.

But what I cannot explain in the case of this problem I have, is this.

I have done some extra tests to illustrate that the problem, at least to my knowledge, lies solely in the camera.
Follow what I did, please.
The only light source in all the tests were the IKEA LED lights.

- I have set the IKEA LED lights to neutral and saved a custom WB setting in slot 1
- made several shots one after another without pixel shift and all had exactly the same settings, exposure and had the same neutral color, no difference at all
- did the same test with pixel shift enabled and made many photo's, again exactly the same results, all were the same and perfect
- made a whole serie of correct exposed images with different shutter speeds, from 1/200 of a second up to 4 seconds, no difference at all and all looked perfect, not the slightest change in exposure or color, all with pixel shift enabled

In all these circumstances (more than 60 test shots were made) the result was: :----------------------------->perfect whites and a very neutral image without AND with pixel shift, even with shutter times up to 1/200st of a second with increments in 1/3 of a stop up to 4".

Then I did the next test:

- changed the IKEA LED light to warm white and made a new custom WB and stored it in K2
- made several shots one after another without pixel shift and all had exactly the same settings and had the same neutral color, no difference at all between them, even with that warm LED light this time
- did the same test with pixel shift enabled and made many photo's, all pictures had the same yellow color and the same abnormal histogram as seen in picture 3 of the screenshots in my earlier post
- made a whole serie of images with different shutter speeds, again from 1/200 of a second to 4 seconds, no difference as above and all stayed equally yellow when pixel shift was enabled

In all these circumstances with the warm LED light, only where pixel shift was enabled, this time the result was: :----------------------------->a completly yellow image and very abnormal looking histogram, but no variations between them individualy.

Now think with me please. If the LED lights would cause possibly so much fluctuations, at least one image should look different, but none did.
But, all yellow looking images looked good in RawTherapee, without any change. Just importing and instantly they showed up with the right colors like all the other normal pictures on my camera.

To me, this is a problem that is caused only in-camera; otherwise the RAW data would show the same yellow results in an external editor as RT and this is absolutely not the case.
RT is set to camera WB, so things should stay the same.

More important, from each ps image, the four individual pixel shift images all look perfect in RT and there is no visible difference between any of those four when you compare them.
Only the miniatures that are imported with the RAW files indeed also exhibits the same yellow color.

As soon as I open the RAW files in RT, the miniatures in the browser panel of RT are replaced with normal colors, see also my earlier post and pictures.
All images, once inside RT, look exactly the same, pixel shifted or non pixel shifted, with warm LED light or neutral LED light.
Only my camera shows these strange colors under exactly these circumstances on my K1 display.

Also Windows explorer shows the same DNG miniatures as yellow pictures with the problematic files, I suppose because they come directly from the camera together with the RAW files?

Don't forget that I already wrote that while taking the ps shots, when they show up as 1...2...3...4 (from top left to bottom right) on my K1 display, all four images appear as perfectly normal colors.
(I know how to look at colors because as a professional photographer I have made about twelve thousand professional prints for a photo studio and worked in a studio for almost ten years)

If the properties of those cheap lights should play any important role in this problem, how is it possible that every individual file of a ps image is perfectly exposed and has perfect colors?
Why does it not happen anymore as soon as I change those same LED's from warm to neutral? Once they are set to neutral, the pictures with ps are all fine, also in-camera I mean.
How can these colors become so very different, but only after the camera has done it's math? This is almost certain a bug.

I can switch off pixel shift and have a perfect image, switch it back on and... bam, a yellow image, off again, normal image, on again, well you get the picture...
Every single time again I get the same results, with no color variation even between the "faulty" ones. I did about 120 shots to test if the results were constant and they are.
Nothing has changed between different pictures, except the pixel shift on or off and the change from warm white to neutral LED setting.
Shutter speeds seems to have not the slightest effect, ISO neither, I tested this also to rule out every other aspect.

Not that I want to push things here to get my answer, but it doesn't make sense to me and I always want to understand why things are happening, it is so intriguing to me.
If someone who knows how the order of calculations is done in a camera like my K1, maybe we can find out what possibly can happen and why only under such specific circumstances.

After all, It is not a random affair that is happening now and then and with each time different results, like you would expect from the complex LED's behaviour.
If I can get constant results with these lights with shutter speeds ranging from 1/200 sec to 4 sec, then I think we can conclude that these light sources are pretty stable.

This problem is reproducable every time again and the colors are perfect, or completely wrong and yellow with always the same wrong histogram as posted before.
If a non pixel shifted image can be exposed correct with a perfect set custom manual WB, then a pixel shifted one directly taken after it under the same circumstances should look exactly the same with that same WB, except a little bit sharper, with a little bit less noise and a little more dynamic range. I don't think anyone can argue with that.
And indeed if I make a whole serie of the same image, there is no difference between any of them.

But again, this is no longer a problem for me, I know what to do and how it only seems to be a problem with the way my camera shows those specific files under those very specific circumstances.
I can perfectly use them in RT and they look exactly like the non ps versions that I took right before and without any work that need to be done. Just importing in RT and they look fine.

Sorry for the long post and thank you all for your patience.

Again Steve, thank you for your help so far.
Have a very good night.
Sven

Added information:
To exclude the possibility that RT should perhaps also play a role in this, I opened the same yellow files in Camera raw 8.5 and the images instantly looked perfect as soon as they were open.
This rules out that there is any problem with the file itself. It can only be the camera.

Forum: Troubleshooting and Beginner Help 12-07-2018, 09:18 AM

Possible bug in firmware K1 with manual white balance and pixel shift?
Posted By Svenneke

Replies: 47
Views: 3,932

Hello everybody,

The DNG files with the problematic pixel shift are between 149MB and 153MB and this exceeds by far the limit that I can upload here.
Also, DNG files are not listed as a possible upload format, at least not here, so I am sorry that I cannot upload a file with that problem, it would be helpefull if others could see and open those files.

The other problem is that as soon as I open the original problematic (yellow) files and open themin RawTherapee (to be able to scale them down in size) the RT software immediatley renders everything correct and the miniature and the exported files are normal.
So, I cannot show what the problem is for those reasons, I'm sorry.

But I don't worry about it anymore because I know now that it is only a problem with the way my camera renders the ps images under these specific circumstances, it is not a problem with the actual RAW file.

Besides, for those who are interested, I think I did found out why this is happening.
The color spectrogram of a (very) warm white LED looks very close to the left example of the attached image. This is exactly the kind of information that I see in the histogram with the pixel shifted versions:
more or less normal red levels, the greens are a little streched out and wider in my histogram (higher in this picture), and the blue is very narrow and pushed to the left in my histogram (low and a small blue spike in the image).

It seems that when I set such a manual WB after a (very warm) color measuring in-camera from a white paper, the camera can make a very neutral white balance and does use that color balance correctly when I don't use pixel shift(K1-3).
But as soon as I activate pixel shift, the camera uses the colors in respect to the way the colors are emitted from the LED, as seen in the left image.
For some unexplicable reason, this only happens with pure LED light and only when it is set to warm white, at least with those IKEA lights.
I looks like the camera "forget" to apply the measured WB when it does pixel shift.

It does not happen with any other setting with a combination of mixed daylight or tungsten and more neutral light, nor with any other mode for choosing the WB in-camera.

The results with these IKEA TRADFRI LED's are the same, every time again I perform this test.

So, for members or viewers who experience this "problem" and visit this page for the first time, I summarize what I know so far:

The K1 can measure a manual WB (K1-3) and it does that exceptionally well.
When you set the WB this way and take a shot without pixel shift enabled, everything works as it should.
But, if your only light source is a LED with a very warm white balance AND you enable pixel shift, the camera can render a very yellow image.
That image seems unusable, but the RAW data shows up fine in a RAW editor and the file is perfectly usable.
It seems that the camera does not apply the setting for the WB at all with these pixel shifted pictures, hence the very yellow color shift (see my earlier posts with the screen shots from the K1 display).

So, I hope this can help someone in the future who should stumble onto the same problem as I did.
Do not panic, the files are OK, it is only the camera that cannot show them correctly.

Have a good night and thank you all for your kind help and good suggestions.
Greetings,
Sven

Forum: Troubleshooting and Beginner Help 12-06-2018, 01:57 PM

Possible bug in firmware K1 with manual white balance and pixel shift?
Posted By Svenneke

Replies: 47
Views: 3,932

Hello pentageek,

Sorry for the delay, I am sick since yesterday evening. As soon as I feel better I'll try to post a dng file.

Goodnight everybody.
Sven

Forum: Troubleshooting and Beginner Help 12-05-2018, 03:00 PM

Possible bug in firmware K1 with manual white balance and pixel shift?
Posted By Svenneke

Replies: 47
Views: 3,932

Goodnight pentageek, thank you for asking.

Are you sure that the only lights visible are these IKEA lights set to warm white?
I also could not replicate this phenomenon with any other light source and with the same IKEA lights set to neutral or cool white.
As soon as there was also any source of other light in the measurement, it did not happen.
I am already in bed now and will try to upload a dng file tomorrow.

I wish you a good day or night, depending on your location.
Greetings,
Sven

Forum: Troubleshooting and Beginner Help 12-05-2018, 01:58 PM

Possible bug in firmware K1 with manual white balance and pixel shift?
Posted By Svenneke

Replies: 47
Views: 3,932

Hi Steve,

I understand what you mean. I already tried to find a direct contact adress but got lost in all the different countries and to be honest, I am not sure where to adres this problem to. Where are the engineers located who write things such as the firmware? If anyone can point me in the right direction, I'll be glad to write them about this experience.

FWIW, I absolutely love my K1, it's the best piece of fine engineering that I have ever bought. For me it does everything I ever wished a camera could do and much more and the quality of the images is exceptional. I am happy that I stayed loyal to PENTAX for so many years, being able to use my old but still very beautiful full frame A and A* lenses again. And I have to admit, the PENTAX community is great!

Happy shooting everybody,
Goodnight,
Sven

Forum: Troubleshooting and Beginner Help 12-05-2018, 12:28 PM

Possible bug in firmware K1 with manual white balance and pixel shift?
Posted By Svenneke

Replies: 47
Views: 3,932

Good evening Photoptimist, you are absolutely right. RAW data contains no information on white balance, it is a conversion that depends on a setting the photographer chooses or the camera when on automatic mode. I am very aware of how this works. But thank you for your kind explanation.
Yes I did the test with tungsten WB and the results are normal, no strange yellow color shift.
Also I tested it with all other possible settings regarding white balance. So, only manual white balance and only in combination with pixel shift and as it seems now, only with the very warm IKEA TRÅDFRI LED lights set to warm white, causes this.

Hi Andrea K, that is what I did already and each of those four files are perfectly normal, no color shift in any form.
So, to summarize, this is what happens with the IKEA lights set at warm white:

- Choose manual white balance, set custom white balance with shutter and store it in slot 1-3, choose OK.
- Set the camera with a long enough shutter speed to prevent the possible faults caused by the fast flickering of LED lights (1-3 seconds)
- take the picture without pixel shift, result: perfect exposed and with a very neutral white balance
- leave all settings as they are and only enable pixel shift, result: during recording all four pictures looks normal
- camera starts calculations, result: very yellow image with the blue channel almost completely pushed into the left of the histogram
- change camera back to non pixel shift, normal result
- change camera once more to pixel shift, but set IKEA TRÅDFRI to neutral or cool white and take a picture, result is normal again

What is happening in the camera? I have to agree with photoptimist that this must be a bug in the firmware.
RawTherapee also sees a yellow thumbnail when importing all pictures from camera with this pixel shift problem, but immediately renders a new neutral picture (and miniature in the programs explorer panel) as soon as the file has been openend in the developers panel. All four individual images from the problematic yellow original RAW files are always looking perfectly neutral without any change in the settings of RawTherapee and the problem is also not present when exporting a tiff or jpg from these files in RawTherapee. The exported images are looking exactly as the non pixel shift versions.

However, rendering that same problematic RAW file in-camera and saving it as a jpg or tiff file, results in the same yellow image once saved to an internal sd card of the camera.

It is not such a big problem because it can be solved, but it should not happen under these specific circumstances because you cannot rely on the colors that are rendered in-camera, nor on the histogram that the camera makes from this. The blue channel is now very narrow and pushed into the left side, although the RAW files in RawTherapee do look normal.

Good evening everyone and thanks once more.
Greetings,
Sven

---------- Post added 12-05-18 at 01:00 PM ----------

Hello Steve, a big thank you for your help.

When importing the pictures in RT, I leave every setting untouched and the setting "camera WB" is set as standard so nothing changes. So, if I'm right, there should be no change at all when exporting, correct me if I'm wrong please. The exported ps image does look exactely the same as the non pixel shifted original, without importing and without any editing, so they almost must be identical once saved as a jpg or tiff.

Regarding the known problems of working with LED lights, I do have the experience to choose a long enough shutter time. Here in Belgium, the frequency of our power grid is 50Hz. Everything above one second exposure should be sufficient to prevent any possible fluctuation of the LED lights during micro seconds. These lights are pretty stable in comparison with, for example, TL lights which do flicker. At least I can sea that easily, but not everybody is as sensitive, some of my friends do not see that. The IKEA lights don't show any sign of flickering for the eye.

So I don't worry about using LED lights, I am used to them because I use specialised LED lights in my 3 softbox setup all the time without any problems.
Even those IKEA lights in our living room behave very stable and every picture I take with them is good enough to be used. The only combination that causes is what I wrote before. Although, each problematic file contains four perfectly usable individual images, so the LED's don't play any role in this problem, at least that what I can conclude from the results.

To me it seems as if the in-camera rendering is not able to render the combination as it should do normally, but under these extreme conditions only. How else could such a yellow looking file contains only four perfect images? If the cause should be the LED fluctuations, than we would see these variations in each individual image of a pixel shifted version, and this is not the case. I cannot detect any difference between any of these four images, not the slightest.

Steve, I agree completely with your conclusion, we should be aware of these possible problems,with LED lights

I hope PENTAX will read this an can find a fix for this, but in the mean time, now we all know that these files are perfectly usable, once imported in a RAW editor.

Again thank you all, it is indeed an interesting topic, it seems.
Goodnight.
Greetings,
Sven

Forum: Troubleshooting and Beginner Help 12-05-2018, 10:12 AM

Possible bug in firmware K1 with manual white balance and pixel shift?
Posted By Svenneke

Replies: 47
Views: 3,932

Dear all,

I noticed another no so normal behaviour. When I opened the file browser in RawTherapee, I saw the original pixel shifted files as yellow miniatures, just like on the display of my K1. As soon as I opened and developed them, they seemed normal and afterwards after exporting a jpg, without making any changes on the RAW data, the miniatures looked normal. See my 2 attached print screens begore and after.
Maybe someone has any idea what can cause this behaviour and solve this problem.

Since these yellow colors are only visible in the camera and the minitaures, I am inclined to think it is a rendering problem. The RAW files are perfectly normal.

Have a good night.
Greetings
Sven

---------- Post added 12-05-18 at 10:15 AM ----------

Sorry, the pictures are reversed in order, first the yellow without opening, afterwards the neutral version after saving without any change.
IPad's are not that handy for posting things...
;-)

---------- Post added 12-05-18 at 10:59 AM ----------

Hi everybody,

Determined to solve the reason why this happens I found out that it solely depends on which color the IKEA LED's are set.
The IKEA TRÅDFRI dimmable led's can be switched between warm white, neutral and cool white.
The strong yellow color as seen in the images above, are only visible when the LED TRÅDFRI is set to warm white, even if I have made a manual white balance beforehand. As soon as I change it to neutral or cool white, the problem went completely away. Color temperature is alway set with a new corresponding manual white balance. The results with the last two settings are perfect and there is no color shift whatoever, the same long shutter speeds are used to prevent the influence of the 50Hz flicker.

For some strange reason, the in-camera rendering goes wrong when set to a manual measurement with the (very) warm white IKEA TRÅDFRI LED's. I could not reproduce this with any other lights available.

Thank you all for thinking with me and suppose ideas.
Have a good night.
Greetings from Belgium

Forum: Troubleshooting and Beginner Help 12-05-2018, 09:38 AM

Possible bug in firmware K1 with manual white balance and pixel shift?
Posted By Svenneke

Replies: 47
Views: 3,932

Hello Steve, thank you very much for your answer.

AWB was not possible because the LED's emmit a very warm color, so warm that even with AWB the colors were much too warm and far for the neutral white that manual white balance privided me with.

In the mean time I did the test to open the (corrupt looking?) yellow files in my software of choice, RawTherapee.

The miniatures that are visible straight from the camera show the same yellow colors and indeed again only with the pixel shifted versions.
However, when I open these files in the developers panel in RawTherapee they look perfect and are exactly like the non pixel shifted versions, leaning perfect white balance and absolutely not a hint of tha yellow color it shows in-camera.

I opened all four individual images of the ps version in RawTherapee and they all are perfectly exposed and colored.
So it seems that my camera is rendering or interpreting something wrong when combining these four, but the RAW data in the DNG files are fine and perfectly usable.

That is good to know because now I know that these faulty yellow looking images do contain the right data in the RAW file and are perfectly usable, only not straight out of the camera.
Perhaps PENTAX should look into that if they can reproduce these circumstances?

Thank you for your time and effort to help me.

Greetings,
Sven

Forum: Troubleshooting and Beginner Help 12-05-2018, 08:54 AM

Possible bug in firmware K1 with manual white balance and pixel shift?
Posted By Svenneke

Replies: 47
Views: 3,932

Hello everybody,

As some members asked and promised, I did a test outside with daylight and it works as it should, with and without pixel shift in combination with manual white balance.

After that I went back inside and took the same picture with a combination of the IKEA LED lights and daylight that still was entering the living room. No problems at all.

As a third test I closed the curtains completely and tested it with only the LED's and those yellow color was back after calculating the pixel shift, but it was not visible during the four exposures on my screen. These four exposures looked perfect again, until the calculation was finished and then the same images combined were as yellow as could be.

As long as the manual white balance was mixed with enough daylight, the results stayed normal, but as soon as I only had the LED's as light source, the histogram for the blue channel was completely skewed to the left allost leaving no data at all, resulting in a yellow image.

I will not investigate this further, but I want to warn everybody that this can happen under certain circumstances. If this happens, simply use any other white balance setting that fits the needs, or disable pixel shift. These results are reproducable every time with my K1. Perhaps someone can do the test and see if it is an exception with my camera or if it happens in all camera's. (Updated tot firmware 1.43)

Happy shooting everybody and thank you all for the help.
Greetings,
Sven

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