Nikon D3100 2x Teleconverter (4 Elements) + Nwv Direct Microfiber Cleaning Cloth.

I really like this doubler. It works well on my camera and lenses. I used it primarily with my AF-Nikkor 70-300mm VR lens. I have to turn VR off to get a lock using autofocus. I have also used it with my 650-1300mm lens.I haven't done any benchmarks to evaluate optical quality, however I have taken a number of shots and have been pleased with the results. I like the construction of the doubler, its quality is better than expected. The doubler rattles a little bit, it's the aperture control mechanism. This lens is wide open, there is no aperture setting on it. However the automatic aperture settings on the 70-300mm lens still works fine. You might want to use aperture priority and open up the lens a bit to ensure that adequate light is transmitted through the doubler.Overall, I'm very pleased with the doubler.

I can't give it less than a star... if I could I would do it with no doubt. The seller shipped the item in time. When I mounted it, it was impossible to focus, neither in manual nor ate-focus mode. Which it was supposed to support.I review it just to make myself sure that it was for Nikon F lens and not Cannon or other mount, and, it was the right product. Not sure if it was damaged when shipped. I finally decided to return it and I was refunded but, not in full. There was something lie a 10% retention fee or so.

Have to manually focus but no problem.

This is a great product for the price it works with our nikon D3100 it is a little slow to focus but hey we are not professionals and it takes all our pictures just awesome. We live in Alaska and all our pictures are crisp even the Dal sheep way up on the rocky ridges.

To shoot baby owls in nest. The autofocus doesn't work at all focal lengths. Photos at 400 mm are acceptable.