A couple of images of Blue Dasher Dragonflies. The Featured Image of the male Blue Dasher was taken with a 400mm DO lens with a 1.4X Teleconverter @ f/8 on a Canon 1D mkIV. To get the smoother background I wanted I only stopped down 1 more f/stop to f/8 since I already lost 1 stop with the 1.4X Teleconverter attached. My usual workflow when (on bright days) using teleconverters for a little more sharpness is to stop down at least 1 additional stop when using a 1.4X and at least 2 stops when using a 2X teleconverter. If I am using a 3X Teleconverter I would stop down 1 or 2 more stops than when using a 2X Teleconverter if I could. But then again a 3X Teleconverter usually is so bad I would just stack a 1.4X & 2X teleconverter. If using an extension tube on Telephoto lenses to get closer focusing I would also stop down at least 1 or 2 more stops for more depth of field.