Cosina-made 4x zoom, with a tripod foot. My version is Yashica/Contax mount. Lens size closed, with a Panasonic G2 mounted on the back. Lens size racked out. Given the extremely narrow field of view, you aren't going to be handholding this lens. It magnified any instability in my tripod. All of these shots were taken at 500mm. I'm pretty impressed, this lens doesn't seem to have the greatest resolution for cropping, but it zooms from 100 to FIVE HUNDRED MILLIMETERS! All of these photos are uncropped. I didn't have much time to take test shots this afternoon; it got darker much more quickly than I expected. I'll try to get some more soon. Little bird gang Turtle reflection Moon. I just pointed the lens upward, and zoomed in. This is with no cropping. I'd say pretty good reach. I got perfect infinity focus with an RJ camera adapter.