Tonight, after picking up a second hand Kenko Teleplus 2X Teleconverter, I thought I'd give it a test before moonrise. I coupled it with a 200mm Sun prime lens for an effective focal length of 400mm and shot 3 x 120sec unguided subs at 1600 iso using my modded Canon 550d and UVIR cut filter. Patchy cloud and the roof of my house prevented any further data being collected but I was relatively pleased with the result shooting jpegs with no calibration frames. Costing just $10, this TC was a real steal!