Does the camera white balance setting affect the raw image at all?

Question

Does a DSLR's white balance setting (whether a preset like cloudy or a custom WB setting) affect the raw file at all, or does that setting only determine the WB of the JPG that the camera generates?

A related way to ask this is whether this procedure makes sense: 1. shoot in RAW mode only 2. set the white balance using a gray card, but not by taking a picture of the gray card

If the WB setting only affects the JPGs and not the RAW files, and you want to shoot RAW only, then you must have a photo with the gray card to use in post processing.

Answer 1

The white balance setting doesn't affect the image data in the RAW file, but the setting is recorded in the meta data in the file, so you can still use it to process the RAW image if you like.

Answer 2

Short answer: No, changing the WB does not affect the RAW image.

But you don't need a gray card to shoot RAW and get a WB; the camera can provide you with an auto WB, or you can select one prior to your shoot, either through a gray card or through a camera preset.

So here's a tricky WB situation: you're shooting in a church with different naves. One has a gold chalice that the light from a stained glass window is hitting and bouncing everywhere, and everything looks pretty cool. Back and the main altar, you've got light from all over, maybe from incandescent lights above. You're moving back and forth between shrines during the wedding/baptism/whatever. Switching WB might be very tricky to do on the fly, and fraught with the possibility of a mistake. For this, I'd shoot the gray card in both areas ahead of time (if possible, if the light isn't changing much) and then apply the appropriate white balance setting to your raw file later.

In practice, I almost never use a gray card, and several of the other wedding photogs I have worked with have also ditched their gray cards as well. The Auto WB setting in the Canon and Nikon bodies is good enough, and the light changes so quickly, that shooting in RAW and then fixing the rare mistakes made by the auto wb is easier and faster than using the gray card.

Answer 3

The white balance setting selected on the camera is stored in the RAW file; however, when processing the file, you can choose to "develop" it using an alternate setting (most software also supports an eye dropper mode to select the white balance based on a known even tone within the image).

Answer 4

The answer to this can also be "depends". Some cameras apply filters filters like denoise to the raw data before saving it. Without getting manufacturer to assert something, we can only say that most cameras currently do not apply white balance to the sensor data before saving it.

Answer 5

As far as I have heard, the WB does not affect the RAW data, but it does affect the exposure.

So in difficult lighting situations the camera auto exposure might react differently depending on the WB.

Sadly I got no source for this information.