[Gian]

Hi All,

the other evening I was taking a landscape picture after the sunset, camera on tripod.

After a few shots, I thought I'd try to use the flash, even if the closest subject seemed too distant.

In fact, the flash intervention is close to null, but the sky is purple instead of blue.

I only shoot RAW, so this is fairly easy to correct, but I wonder why the flash would change the camera WB.

Happy New Year to all Pentaxians!

-Gian

Attached Images

 

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Last edited by Gian; 12-27-2019 at 10:59 AM. Reason: add attachment

[manishved]

It also depends on your exposure settings. What was your WB settings?

[Gian]

the pictures where take in sequence, the first one 4", and the second one 8", WB is always AUTO.

[CarlJF]

There's a custom setting for the WB with flash. I'm not sure what the default is, but it might be set to some specific WB. The first picture is with the WB you set on the camera while the one with flash used the WB from the custom setting. Thus the different look on the two pictures.

[ismaelg]

I guess the camera switches automatically to Flash WB when detected. Flash WB is somewhat similar to Daylight WB.

Thanks,

[stevebrot]

I only shoot RAW, so this is fairly easy to correct, but I wonder why the flash would change the camera WB.

The default for flash is Auto-WB.

The short answer, when using Auto-WB, is that the flash changed the light for the exposure and that the camera changed the WB to suit. Auto-WB is assessed after the exposure during processing for the embedded JPEG in the DNG/PEF file with the area of flash illumination being evaluated along with the ambient lighting. With your K-3, the WB behavior with flash and custom menu (C2 --> WB When Using Flash) are summarized on page 53 of the K-3 Operating Manual...

• Auto WB (default)
• Multi Auto WB
• Flash
• Unchanged (I did not test, but believe WB follows non-flash WB setting, whatever that is.)

Steve

[Gian]

It is so indeed, WB When Using Flash was set to Auto-WB.

But, if the camera is also set to AWB, why are they different?

[stevebrot]

But, if the camera is also set to AWB, why are they different?

Because the light is different due to the flash contribution and Auto WB is evaluated after the exposure, not before. (It may not be clear from the manual, but Auto WB with flash is the same as Auto WB without flash.)


Steve

[Digitalis]

I wonder why the flash would change the camera WB

If you have altered Custom function 11 on your camera, it defaults to auto White balance, but you can set the camera to automatically change the WB* when flash is used which caused the shift in colour. Personally I keep my camera with a fixed WB. A fixed WB setting of 5000K gives you a good reference point to figure out what correction is needed to achieve accurate colour. And as it happens 5000K covers a lot of ground with common light sources, it is a good average value for work under sunlight.

*Flash WB is typically 5000K