Sunday, February 17, 2019

Yellowstone White Balance and Exposure

A lot of the images captured on our recent trip to Yellowstone have a nasty blue tinge.  Many of those that don't have the nasty blue tinge have really grey snow.  Both of those issues are artifacts of digital cameras, typically running in auto mode trying to take great pictures under lighting conditions that are anything but great.

Through most of our trip we had heavy cloud cover which fools many cameras into shooting at much too low of a color temperature (the variable controlled by white balance).  This results in a very blue image.  Here is an example (not a great shot, but a good example).

Image as shot: Yuck!

The solution to these problems is to help the camera's tiny brain by dialing in an appropriate white balance and exposure compensation.  This can be done before the shot through camera settings or after the fact in post processing. 

Setting white balance and exposures compensation before the shot is particularly important on cameras that are shooting JPEG (or JPG) images.  The JPEG format tries to optimize images and compresses data from the camera sensor before storing it.  The compression makes the optimizations something that are very hard to change in post processing.

Cameras that are shooting in RAW mode store essentially all of the data from the camera sensor allowing adjustments to be made freely in post-processing.  This is the mode that nearly all of our BarrettPhoto shots use.

The as-shot image shows Elk driving through deep snow in a heavy snow fall.  It is very dark with the snow a pretty sorry shade of grey blue.  The sun was covered by very heavy cloud cover, so heavy it could reasonably be called total shade.  Dialing in SHADE as the white balance results in this image:

White Balance: Cloudy (at least the blue is gone)

It's still way too dark, the snow is now grey, but it is no longer blueish.  That's better, but still not good.  The exposure needs to be increased by about one full stop to make the snow appear white, that is look like snow:

Exposure compensation +1

That's about as good as it can get when shooting in JPEG and setting white balance appropriately and boosting exposure by one stop. 

Taking advantage of RAW mode, I can tweak the settings a bit further to find the following image:

Final RAW adjustments (EC +1.5)

It's still not a very good image, in fact I think it's totally unusable other than to tell the story of our trip (something I value), but it does illustrate the impact of white balance and exposure compensation.

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