Panasonic DMW-STC20 Lumix S 2x Teleconverter

The build quality is excellent, this teleconverter fits securely to my Panasonic 70-200 f2.8. I can move about with confidence and am also very happy with the autofocus. I've perceived no difference in autofocus performance. There is a minor decrease in sharpness, which is to be expected in a teleconverter. The decrease in sharpness is worth the reach for video and most of the time for stills. I report most of the time because the S1 does well with cropping images. If you find yourself at 200mm cropping significantly, this teleconverter will most certainly help retain an image that fills the frame. At the time of writing this review, there is no L-Mount super telephoto lens appropriate for wildlife or sports. This teleconverter is not an ideal substitute for such a lens but works for a great many scenarios, especially video. Ultimately the 70-200 f2.8 with teleconverter is significantly more workable for me than a sigma 150-600mm f5-6.3

The longest lenses made for the Leica L mount are the Panasonic 70-200 and the Leica 90-280. The latter is extremely large and expensive. I have been happy with the IQ of the Panasonic 70-200 (f4) on the Leica SL2, but needed extra reach for a trip to Yellowstone. The images with the 2x were OK, but (sort of as expected) not as sharp as with the native lens, especially when cropped (see images) and shooting handheld. I took it off the lens for the last day of shooting. I will buy the Panasonic L mount super telephoto zoom when it is released, and only use the TC when I absolutely have to have the extra reach.