Extension tubes

I always carry at least two extension tubes with me.  They are extremely light (because there isn't any glass in them -- they are essentially spacers), they take up little space, and when placed between the camera body and a lens turns that lens into a close-focusing optic.  In this case, I photographed the yellow-beaked cardinal at a feeder in the Pantanal with a 500mm lens, a 1.4x teleconverter, plus two extension tubes.  I was about eight feet away from the bird, and the minimum focusing distance of the 500mm lens is about 14 feet.  It was the tubes that permitted me to focus so closely. Imagine being able to focus a 700mm telephoto (500mm plus the 1.4x converter) to only eight feet!  My settings for this were 1/200th of a second, f/5.6, 1000 ISO, and I used a tripod with a Wimberly head.