wrong color temperature Godox ? Do I do something wrong

[rlast]

So it would be interesting to check that flash with another camera. Maybe the specs of the flash are just wrong. And then Rudolph can ask the manufacturer for an explanation of the results of the done tests

George

I will see what I can do George, as indicated I don't have other equipment at hand, and my flash is only suited for Sony camera's. …. I thinking on a way forward.
Thanks for your comments

[rlast]

... except that it puts numbers to Rudolph's main concern - the white balance accuracy. It states that the camera's neutrals (Adams' Zones II to V) are indeed gray to an accuracy of +/- 1.6 delta-Chroma which is quite good in my opinion and in CIE's opinion too (google 'just noticeable difference'). Certainly much more accurate than the measured a*,b* values of the posted images!

Thanks Ted, thanks for confirming my camera should not be too bad …! That's the only thing I wanted to learn, by posting this image! :-)
Rudolf

[rlast]

When I open my gray card shot done under flash using Capture One, I get a value of 5583K, which is darn close to the nominal 5500K, not the 7200K Rudolph is getting.

Thanks for posting your result Manfred. And your result is very close to where you expect it ….

Can you describe the setting in a simpel way ? (studio? )
Thanks, Rudolf

[xpatUSA]

[data from a well-known test house] should count for very little because it is irrelevant to the issues that Rudolf has here.

I think you owe it to the rest of us to explain why you think a camera model's response to X-rite ColorChecker gray patches is irrelevant to that very same camera model's response to shooting a gray card.

The question that was raised is why Capture One is showing 7200K colour reading from his test rather than something closer to the nominal 5500K he could reasonably expect.

I am well aware of the original problem, thank you!

The Imatest result is NOT going to answer that question.

Please tell me where I said that it WOULD. The Imatest result for both Rudolf's and your camera shows quite clearly that the cameras will render neutral colors correctly with all other things being equal. I would believe Imatest's shot over Rudolf's any time (no disrespect intended to Rudolf) and Imatest's result is no less real than shots of nekkid wimmin. LOL. Less pretty, though.

[Manfred M]

I think you owe it to the rest of us to explain why you think a camera model's response to X-rite ColorChecker gray patches is irrelevant to that very same camera model's response to shooting a gray card.

Actually, I believe it should be the other way around. You could perhaps start by explaining how the colour response of a particular camera body done under lab conditions with a different light source and target compares to a different camera body shot in a totally different environment (light source, conditions, target, etc). The only commonality between the tests is that the same camera model is being used.

This is something commonly referred to as "comparing apples and oranges"...

I am well aware of the original problem, thank you!

Good...

Please tell me where I said that it WOULD. The Imatest result for both Rudolf's and your camera shows quite clearly that the cameras will render neutral colors correctly with all other things being equal. I would believe Imatest's shot over Rudolf's any time (no disrespect intended to Rudolf) and Imatest's result is no less real than shots of nekkid wimmin. LOL. Less pretty, though.

The Imatest result is for a specific camera body that is NOT Rudolph's camera body. If this were a design or manufacturing issue common to both camera bodies we might be able glean something from the test, but I would suggest that this is highly unlikely.

I still suspect that what Rudolph is getting is contamination from his test environment as a result of reflected flash (his methodology appears to eliminate ambient light from the potential issue list). Without more information on his test environment, we have no way to assess that though.

I probably do more flash photography than most people here, so I likely have a better practical understanding of these issues than many. Contamination from reflected surfaces is my most common issue in white balancing a flash image (which is why I like shooting in the studio where I am working in a controlled, neutral environment). The second most common problem I run into is from light modifiers that are changing light colour and I have also run into issues with old flash units where the flash tube has yellowed. In small flash photography, especially outdoors, ambient light contamination is a common issue.

These are all conditions that can be handled in PP so long one does not get hung up on the numeric values shown by the PP software.

[xpatUSA]

Actually, I believe it should be the other way around.

Well, of course you do ...

You could perhaps start by explaining how the colour response of a particular camera body done under lab conditions with a different light source and target compares to a different camera body shot in a totally different environment (light source, conditions, target, etc). The only commonality between the tests is that the same camera model is being used.

Gosh, the same camera model! Proven in testing by a respected web-site to measure neutral colors well enough, JUST LIKE YOUR D810!! So, your suggestion is now that Rudoph's camera is somehow so different that it should be considered broken!!

This is something commonly referred to as "comparing apples and oranges"...

I guess that's payback for "nekkid wimmin", LOL

The Imatest result is for a specific camera body that is NOT Rudolph's camera body. <>

From which we get what? Camera bodies are so variable that poor old Rudolph's is almost 2000K off compared to the one used for the Imatest test !!!!!

Remind me to never, ever buy a Sony ...

I still suspect that what Rudolph is getting is contamination from his test environment as a result of reflected flash (his methodology appears to eliminate ambient light from the potential issue list). Without more information on his test environment, we have no way to assess that though.

I probably do more flash photography than most people here, so I likely have a better practical understanding of these issues than many. Contamination from reflected surfaces is my most common issue in white balancing a flash image (which is why I like shooting in the studio where I am working in a controlled, neutral environment). The second most common problem I run into is from light modifiers that are changing light colour and I have also run into issues with old flash units where the flash tube has yellowed. In small flash photography, especially outdoors, ambient light contamination is a common issue.

These are all conditions that can be handled in PP so long one does not get hung up on the numeric values shown by the PP software.

Oh boy ...

[Manfred M]

Sorry Ted - you still don't seem to get it.

You are looking for a technical explanation where there likely is nothing wrong with the camera or the flash.

Instead, consider this to be an issue with the light. Rudolph's camera and flash are likely working correctly, but for some reason, the light that is reflected from the gray card has a higher colour temperature than expected. There are many ways that this can occur, just as there are ways that lower colour temperatures can occur.

How much flash photography do you actually do Ted?

[xpatUSA]

Sorry Ted - you still don't seem to get it.

Our discussion is getting out of hand and is now of no help to anyone - other than for it's entertainment value.

You are looking for a technical explanation where there likely is nothing wrong with the camera or the flash.

Clearly I have given a false impression of "what I am looking for"! For the record, I have never stated or implied that there is anything wrong with his camera or his flash!

Note: In #86, "Camera bodies are so variable that poor old Rudolph's is almost 2000K off compared to the one used for the Imatest test !!!!!" was English sarcasm, not an actual statement, duh.

Instead, consider this to be an issue with the light. Rudolph's camera and flash are likely working correctly, but for some reason, the light that is reflected from the gray card has a higher colour temperature than expected. There are many ways that this can occur, just as there are ways that lower colour temperatures can occur.

As has already been said often enough by yourself and others in this thread. I do not disagree and I have not disagreed with that theory anywhere here.

How much flash photography do you actually do Ted?

That rhetorical question is a poor tactic, Manfred. I decline to answer.

In future, I'll do my best to post with more clarity in order to avoid these continuous misunderstandings.

I'll leave the last word to you. Should have bowed out when I said I would.

[rlast]

Manfred, Ted,
Both of you thanks a lot for your help.


This was my first topic / post on this forum and the the direction that this discussion is taking gives me an unpleasant feeling.
So, I think we better stop here, and once more, thanks for your individual contributions. Also you George, and all others.

Rudolf

[xpatUSA]

This was my first topic / post on this forum and the the direction that this discussion is taking gives me an unpleasant feeling.

I apologize for "hi-jacking" your thread, Rudolf. Sometimes I don't see eye to eye with somebody - and I can get a bit sarcastic if they persist.

So, I think we better stop here, and once more, thanks for your individual contributions. Also you George, and all others.

Rudolf

I've already exited but stand ready to respond to your good self directly, should you need further clarification ...

[Manfred M]

Ruud - Ted and I tend to get into disagreements from time to time. Both of us have technical (engineering) backgrounds, so tend to have an interest in some of the technical aspects of photography that are probably irrelevant to many photographers. Ted has spent a lot of time on various websites (most of them written by well regarded people in the field), so his knowledge in these aspects of photography often exceeds mine, especially in some of the highly technical stuff.

I also have a practical aspect to my photography. I am not a commercial photographer, but generally spend at least 10 hours a month shooting with flash (both studio flash and speedlights), so have a better handle on this aspect of photography than most. I invite you to look through this site to see my work and hopefully that will give you a level of comfort that I know what I am doing and writing about. Unfortunately, Ted posts very few images here, so his practical knowledge cannot be assessed.

[rlast]

I apologize for "hi-jacking" your thread, Rudolf. Sometimes I don't see eye to eye with somebody - and I can get a bit sarcastic if they persist.



I've already exited but stand ready to respond to your good self directly, should you need further clarification ...

Hi Ted,
Thank you very much for your response, I appreciate that!
I've been a "reader" of this forum, and I certainly like to make use of the knowledge you are willing to share, either via reading or in a direct response!

Thanks!
Rudolf

[rlast]

Ruud - Ted and I tend to get into disagreements from time to time. Both of us have technical (engineering) backgrounds, so tend to have an interest in some of the technical aspects of photography that are probably irrelevant to many photographers. Ted has spent a lot of time on various websites (most of them written by well regarded people in the field), so his knowledge in these aspects of photography often exceeds mine, especially in some of the highly technical stuff.

I also have a practical aspect to my photography. I am not a commercial photographer, but generally spend at least 10 hours a month shooting with flash (both studio flash and speedlights), so have a better handle on this aspect of photography than most. I invite you to look through this site to see my work and hopefully that will give you a level of comfort that I know what I am doing and writing about. Unfortunately, Ted posts very few images here, so his practical knowledge cannot be assessed.

Manfred, thanks for your response, and there is no need for yourself and Ted to introduce yourself as capable photographers! I've been a reader for quite some time, and I've seen and read enough to know that your experience is a valuable asset for many.

Appreciate it if can take from time to time some advantage of that knowledge,

Thanks,
Rudolf