It's winter now, which means it's dark by 5:30, and so when I take the dogs to the wooded park for a walk, and perhaps a little work, it's pitch dark. The tree photo, above, was taken with my iPhone in close to pitch dark, and then manipulated to produce an image. Marvelous tech fits into your pocket these days!
I do not use the e-collar much anymore, as the dogs do not need much reminding even with squirrel, dog, and deer distractions. That said, the e-collars have programmable flashing and continuous light features, which are very useful an night in dark field and forest. A bad video of what that looks like is at the link.