EOS R5: Rename custom white balance images

[DaveKennard]

This issue is probably not specific to the R5. I have several different images on my memory card I can use for setting a custom white balance. The issue is that it's not always obvious which image is for a particular white balance. If I rename an image to give it a descriptive name, then the camera can no longer see it (and so I can no longer use it for setting a custom white balance).

Possibly I can work around this by having the white balance written in very large text at the top or bottom of the image frame when creating the white balance images (so it will be readable in the image thumbnails).

But I would hope there is some other way of doing this based on just the image name, e.g. using a special format to the file name or some method of renaming the files in-camera?

Thanks

Dave

[kvbarkley]

Or use Notes on your phone to keep track. Using specific images is not in the spirit of the way the function is supposed to work. Why not just set a white balance color temperature?

[DaveKennard]

Thanks for the suggestions.

Using notes would work, but it is a more lengthy process than if I can see which white balance the image is for directly on the camera.

I believe (though may be wrong) that more extreme white balance adjustments are available when working with a custom white balance set on an image than manually specifing colour temperature and tint. This would also be an even lengthier process as I would need to use notes to see the specific temperature and tint for each WB setting needed.

If I could rename the WB images on the memory card it would be much simpler and quicker.

[Waddizzle]

I use my Sekonic light meter to measure color temperature. You can buy dedicated meters for under well $100 USD. 

[DaveKennard]

Thanks for the suggestion, I don't think that would work for me though for a couple of reasons:

1) I am often working with filters and non-visible light. I would imagine a light meter is not calibrated for light outside the visible spectrum, if it can even detect it at all. And I would need some way of using the same filter that I am using on the camera to use it on the light meter to restrict it to the same wavelengths.

2) I don't think the manual Kelvin and tint settings on the camera allow as much adjustment as you can get from a custom white balance image. So it may not be possible to get a correct white balance this way whereas you can from a custom image.

[kvbarkley]

If you shoot in RAW you can fix it in post.

[DaveKennard]

For stills, yes. For video I have found it is much better to get the WB correct (or at least near correct) in-camera than adjusting later, even when shooting RAW. And depending on what video settings you use, RAW may not be available.

[DaveKennard]

After doing some experimenting with this, I am now really confused as to how the camera sets WB based on a custom image. It does not appear to be based on the image content. And neither does it appear to be based on the thumbnail content. (Determined by inserting the EXIF of one image into another).

So I'm not sure if there are some specific EXIF values written with the WB and average colour from the center of the image? And then these are just read back to set the custom white balance rather than it being recalculated from the image content? I do note there seem to be several Canon Maker note tags relating to white balance.

[Nick2020]

The custom white balance feature just uses a reference image you select to nuetralize the predominant color cast. If you have mixed light sources, there is still the potential complication that the white balance will vary depending on what light is more dominant in the shot, if you move closer to a window during the day and farther from an indoor tungsten light source, where you initially did a custom white balance, for example.

If you're staying in one spot and the lighting remains fixed over time, and does not shift because of the time of day or cloud shifts. then custom white balance might be a helpful tool. Otherwise, you may wish to dial in a color temperature or use a preset that seems close enough to the lighting conditions at hand.