[CarlJF]

I've done some portraits using a 360FGZ in wireless mode with a K-500. The WB on the camera was set on "Flash", not Auto. However, when i import the DNG in LR, the WB between pictures vary widely from 4800 to 6600, like if the WB was set on Auto.

So, I'm wondering what exactly the "Flash WB" setting is supposed to do ? Is it because the flash was on wireless or because this setting only works with onboard flash ? If it doesn,work, which WB setting am I supposed to use ? I've looked in my 360FGZ manual but it's only written that the flash is balanced for daylight film... Which doesn't tell my exactly what value I should use in LR or set on the camera.

[Adam]

A key benefit of shooting in RAW is that you can change the white balance after the capture It really doesn't matter what setting you use in camera, since after your shoot, you can get LR to recommend a white balance setting and then apply that to multiple files. The flash preset may or may not end up looking good.

The final color temperature will depend on personal preference, the subject, ambient light, and distance from the flash.

[CarlJF]

A key benefit of shooting in RAW is that you can change the white balance after the capture It really doesn't matter what setting you use in camera, since after your shoot, you can get LR to recommend a white balance setting and then apply that to multiple files. The flash preset may or may not end up looking good.

The final color temperature will depend on personal preference, the subject, ambient light, and distance from the flash.

Thanks Adam! Yes, I know, it's easily fix in LR. But still, is it normal that the WB applied by the camera changes when set to the "Flash WB" setting ? I was expecting the WB the be set at the same value for each shots when fixed on a specific setting. Actually, it looks like it was on Auto, not two shots having to same WB. Which is kind of puzzling...

[mcgregni]

Have you checked the file metadata directly? This would prove whether the flash preset is behaving as you'd expect. Is it possible the the temperature figure you're seeing in LR is not actually from the file, but actually the result of an automatic profile being applied by LR upon opening the image ..... Perhaps this profile is carrying out a kind of auto wb process itself. There may be a preference setting to control this in LR..... Perhaps it can be disabled for wb and the fixed value from the file used? Worth checking anyway.

[CarlJF]

Have you checked the file metadata directly? This would prove whether the flash preset is behaving as you'd expect. Is it possible the the temperature figure you're seeing in LR is not actually from the file, but actually the result of an automatic profile being applied by LR upon opening the image ..... Perhaps this profile is carrying out a kind of auto wb process itself. There may be a preference setting to control this in LR..... Perhaps it can be disabled for wb and the fixed value from the file used? Worth checking anyway.

I've checked the exifs and, interestingly, the WB is marked as Auto, although I'm sure it was set on "flash" on the camera. So, it seems that this WB setting doesn't work with a wireless flash... I will do some other tests to check if this applies to all settings or is specific to the "Flash" setting.

[mcgregni]

I'm not familiar with the K500, but many of the models have a custom setting for ' White Balance with Flash' . This may be set to 'AWB', meaning whenever flash is activated the WB will jump to auto, regardless of what you set yourself. You can choose 'flash' or Unchanged also for this custom setting. (this all assumes you're using the built-in flash as trigger, and I'm not sure if that even works on the K500, but you didn't say in your first post).

[CarlJF]

I'm not familiar with the K500, but many of the models have a custom setting for ' White Balance with Flash' . This may be set to 'AWB', meaning whenever flash is activated the WB will jump to auto, regardless of what you set yourself. You can choose 'flash' or Unchanged also for this custom setting. (this all assumes you're using the built-in flash as trigger, and I'm not sure if that even works on the K500, but you didn't say in your first post).

I've done some other tests and what I found out is kind of interesting. No matter which WB is set, with flash or not, the WB value in the DNG Exif is always marked as Auto. So, simply put, the WB button is totally useless if you shoot RAW since it will stay in Auto mode no matter what you set. This setting is only applied when you process to jpg. What this mean is that if you want your picture to all have the same WB, you will have to set it manually on all shots. The K-500 will not provide you a constant WB between shots.

I don't know if this applies to all Pentax camera or is specific to the K-500. But I'm certainly curious to know.

[aleonx3]

I've done some other tests and what I found out is kind of interesting. No matter which WB is set, with flash or not, the WB value in the DNG Exif is always marked as Auto. So, simply put, the WB button is totally useless if you shoot RAW since it will stay in Auto mode no matter what you set. This setting is only applied when you process to jpg. What this mean is that if you want your picture to all have the same WB, you will have to set it manually on all shots. The K-500 will not provide you a constant WB between shots.

I don't know if this applies to all Pentax camera or is specific to the K-500. But I'm certainly curious to know.

I believe if you set the AW to FLASH, the information is recorded in the EXIF and will only be applied to either in-camera JPEG or when you process the RAW file (with default WB set to FLASH). However, flash photography is quite different and complex depending on the subject (in the flash) and in camera setting. I suspect that the WB is treated quite differently than comparable Canikon models, where we commonly see other people's flash photos are usually just 'white' light without any trace of ambient light. Whether it is right or wrong, is a matter of opinion. But IMHO, I rather have a photo taken with a flash that look more natural than being flashed (you know what I mean).

[CarlJF]

I believe if you set the AW to FLASH, the information is recorded in the EXIF and will only be applied to either in-camera JPEG or when you process the RAW file (with default WB set to FLASH).

This is what I expected the camera to do. The problem is that it's not what it does. No matter how the camera is set, with or without flash, WB is always saved as "Auto" in the Exif for the DNG. Or, in other words, the K-500 doesn't do what you think it should do by not correctly saving the selected WB in the exif.

So, when you look at the previews, you think they all have the same WB (because you fixed on the camera) and start wondering what's the problem with your setup because it shouldn't be so cold, warm, or just changing from cold to warm between succesive shots... This was what I thought when I write the original message: something was wrong with my flash or setup. I didn't thought that it was my camera saved the wrong WB data in the exif.

Thus, I'm wondering if this behavior is common to all Pentax DSLR or only with the K-500. Do they all saved WB data as "Auto" in the exif, or do they saved what was set on the body like they should do ?

EDIT
Okay, I was looking at the wrong line in the exif. The problem is only present when a flash is used. Without flash, the WB data is correctly saved in the Exif. With flash, the WB is always saved as "auto", no matter what is set on the body. The problem is present regardless how the flash is used (onboard, external on hotshoe, wireless).

---------- Post added 10-18-15 at 02:01 PM ----------

I've found the problem!

In the C2 menu, item 9 "WB with flash", the default is that the camera forced back in Auto mode when flash is used. Setting it to 2 tells it to use WB as set by the user. This solved the problem.

Thanks again guys for your help!