This type of long focus lens is not all that bad....not fantastic, but not that bad actually. I own one, a Quantaray, which looks a lot like the Rokinon. Rokinon is an older cheap brand, Opteka is a newer cheap brand. I think the majority of these are made by two or three factories world-wide,and are labeled with many different store brands across the various regions of the world. These lenses are long, and light in weight, and need steadying, like a tripod or monopod, for best results. The optical formula and manufacturing process for these T-mount lenses has remained the same for 30 years or so. The quality is not as bad as you might think, and the price of around a hundred bucks is about right. They're good during the brighter weather months, and also now that Higher ISO performance has become so good, the f/8 max aperture is not the liability that it was years ago.