Pan Am 310 East of Shelburne Falls
I exposed this image of Pan Am Railways GP40 310 leading MOED on the afternoon of February 17, 2014. By any measure this scene posed a difficult exposure.
The locomotive is a dark blue, while the scene posed a full range of tones from bright white snow to deep shadows. The train was moving, and there was little time for exposure bracketing.
Using the camera’s histogram, I’d made a test exposure before the train came into the scene, and then made a series of images focused on the composition.
Working with my Canon EOS 7D, I always expose simultaneous Jps and Camera RAW files. Most of the time the in Camera hi-res Jpg proves acceptable, and simply archive the RAW files for the future.
However, in this instance when I got home, I found that the in-camera Jpg appears to bright to my eye. I re-checked the camera’s histogram for that file and confirmed that the image was exposed correctly.
In previous posts I’ve explained that with modern digital imaging old-school film-based assessments of ‘under’ (too dark) and ‘over’ (too light) exposure do not allow for the most accurate way of selecting exposure. (see: Snow Exposure—Part 1)
Instead of using the image at the back of the camera, or even the photo on my home computer screen, to judge exposure, I use the histogram. This graph allows me to select an exposure that maximizes the amount of information captured by the camera on-site.
In this case, although the Camera processed Jpeg seemed too bright (over exposed), the camera RAW file was perfect. Since the problem was in the camera’s translation of the RAW to Jpeg, the solution was simple:
I converted the RAW to a Jpeg manually, which produced a result that matched the scene. This retained excellent highlight detail in the snow, produced a pleasing exposure for the side of the locomotive and hills beyond, while retaining good shadow detail in the tree at the left.
I did not manipulate or adjust the file except to scale the image and convert it to a Jpg for presentation. (the RAW file is far too large to up-load effectively).
For more on snow exposure see:
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