Summary: I did a lot of research before purchasing this product, and found the prior Reviews helpful, and helped me make the decision to purchase this item. For the money, it was the best lens available and had the best Reviews. That being said, it is strictly a manual lens, fixed @ 500 mm with an f/8 aperture. It does take a little patience to get it dialed in, but once there, it produced some fine photos.
Summary: Took some getting used to, but I like it for long distance pictures of plants, flowers, rocks and moon shots. Only issue I had was the T-Mount adaptor. One of the screws comes loose that holds the threads for the lens resulting in inability to unscrew it from the lens to attach a teleconvertor, or inability to unscrew the teleconvertor from it. Or inability to tighten it resulting in wobble.
Summary: Not that it's not good...but right off the bat I noticed that's it's totally manual...I wanted to do wildlife action shots...I have no time to manually set this thing...shot would be long gone...Sorry...my two.