Summary: I had this lens for about 6 months now. I concur with the comments about how sensitive this lens is when focusing it. My seems to "recoil" if I let the barrel go. Doesn't matter if you hand hold your camera or if it's on a tripod, the focus will creep on you. So I hold the barrel to ensure that I am getting the focus I need. I also figured since that my lens is new, I "break it in", I'll loosen the barrel up enough so that it won't creep (as much).
Excerpt: Nice lens for price. It will do nicely for what intend - nature/wildlife photography. A bit heavy, so a tripod will be needed most often.<br /><br />Only complaint, it should be sold with a mandatory choice of adapter mount. Received the lens then realized even though I had searched using the following "mirror lens for Nikon D5200" the hiit appeared as if it were fully compatible with my camera
Great lens for the price.... BUT, not for everyone!
James L. Eubanks III "jimbo", Amazon
5 May 2014
Summary: I have owned this lens for over a year now and I have come to love it for what it is. If you are a beginner or impatient, DO NOT mess with this lens. It requires training your eye to see the little pop that you get when you come to focus as the focus point is as thin as frog's hair!! I have been doing astrophotography for about 7 years and have become accustomed to focusing at very long focal lengths. This helps a lot with this lens.
Summary: I read all the reviews. I have used manual lenses in the past so I was prepared for all that. The thing I was not prepared for was the absolute critical focusing. There is no leeway. I should have realized that at f/6.3 there is no depth of field on closer objects. I only knocked it down one star as the price was great for what you get. For my uses, it is too powerful. I wish I had bought the 400mm lens. This is my fault, not the fault of the lens. Live and learn.
Summary: The mirrored telephoto is not as sharp as a good glass lens. But, when you consider the wide disparate price of the two, it is a good lens. I found that there was a lot of flare degradation to the photos that I took. Luckily, a black felt lined interior of a common coffee can makes an exact fit as a lens hood which took virtually all of the lens flare from extraneous light out of the picture.
Summary: Totally awesome! I was able to handhold on a dreary, cloudy day and get a crisp shot with a Canon T2i using it without the 2x adapter. I've uploaded a photo showing the same shot with this lens at 500mm, this lens with the 2x 1000mm and the same shot with a Canon 18-55mm lens at 18mm--if you're using the Amazon Android App you probably cannot see user photos--use a browser (Chrome, etc) to see user photos.
Excerpt: We needed a 500mm lens for a video project where the camera stood a 50-50 chance of ending up in the water. I wasn't willing to risk a Canon lens (or a 5d camera) that cost several thousand dollars, but this $150 Rokinon on a Canon Rebel T2i did the job nicely. You have to work within its limitations (i.e., single aperture stop and lack of contrast), but we were able to fix everything in post-production.