Daeberethwen Arbenlow has a 20 minute video (3/27/2016) on controlling your Windlight settings for photography in Second Life. She uses the Firestorm Viewer and the Photo Tools feature it has. Those using the basic Linden viewer can accomplish the same changes to Windlight, just not as easily nor will the video help you learn how to use the Linden viewer, just the Firestorm viewer.
Daeberethwen does a good job of explaining all the settings and what they do. Along with the verbal description is the video example allowing you to see the changes.
Firestorm has the best set of features for photographers and machinigraphers (or is that machinamists?).
