Ever since I started shooting images seriously for my A Picture A Day project in 2007, I’ve been shooting in RAW format. RAW saves all the image data the camera collects with minimal processing, as opposed to jpeg which applies color correction, sharpening and image compression to create a final image. By shooting RAW I retain the full 14bits of color, giving me greater latitude for processing afterwards in Lightroom or Photoshop. I have found that I have one to two stops in each direction of exposure latitude allowing me to bring up detail in shadows and highlights without sacrificing one for the other. It also means that I can adjust the white balance afterwards with no penalty – I leave my WB always set on Auto and select the proper color balance later.
Here’s an example of a shot that would have been impossible otherwise, shot with available light at the California Academy of Sciences. First the ‘BEFORE’ image, showing what you’d get without saving the RAW version:
BEFORE
The penguin exhibit is at the end of the Africa Hall – a space intentionally left dark to highlight the dioramas. The area above the water is brightly lit – seemingly daylight in intensity. Below the waterline it is quite dark, but our eyes have an enormous dynamic range and pick up plenty of detail in the shadows in the water and highlights on the rocks above the water. A camera however has a much more limited dynamic range. The image above shows the best estimate the camera can give to balance this range when it tries to create a final jpeg compressed image. Neither end of the range is usable – the water is too dark to see anything and the highlights above the water are completely blown out. Can you even tell there’s a girl reaching out to the curious penguin?
But the camera actually saw a much greater dynamic range than this and saved it in the RAW file. By splitting the image in Lightroom and bringing the exposure up a stop in the bottom and down a stop in the top a balance more in line with our perception of the site is achieved.
AFTER
Yep, that’s the picture I thought I was taking.