One advantage of working from a home office is that the camera is always on-hand. My D300s is mounted quite often to the tripod with the Sigma 50-500 attached, so I don't waste much time if I see anything interesting outside. We live in a wooded area and there are always at least a few birds around. During my lunch break today I recognized that the birds came more frequently to the bird feeders than during the last few days with their relative mild temperatures. This is usually an indicator that we might get some snow and colder weather. Light was only good for 1/45s at 500mm and the maximum aperture of f/6.3. The birds, mostly chickadee, nuthatch, or tufted titmouse, were moving too fast for a sharp image. And this is when the speedlight-mounted softbox becomes really useful for some fill flash. I wrote about this little DIY-project some time ago HERE. I built this little softbox mainly for my bird photography in the winter. It allows me to shoot 1/250s, even on a day with gray overcast. The other benefit is that the colors turn out more vivid. 1/250s is still too slow to catch all the action, although it is fast enough to capture the birds during the moment when they rests briefly on a branch before take off to the feeders. Usually the chickadees and titmice stop only for about a second. They never become really motionless because the little branches vibrate under the impact of the bird. The light thrown at the bird from the softbox is subtle if you find the right setting at your speedlight. It may take a few shots before you like the results. Another good point for using the speedlight is that it can produce a nice catch light in the bird's eye that is away from the sun.