Excerpt: Really liked the feel of this lens but I could NOT get a good focus. I use a VERY stable surveyor's tripod modified for the camera mount along with a remote shutter release. I tried, tried and tried to get a good focused picture, in different light from bright sunlight to full moon pics, but could NOT get a decent focus. Reading other reviews, I hope this is just the lens I received but thought it was worth sharing the experience.
Summary: Great lens, but one word of caution. There is no image stanilization on this lens, a tripod is required. Also you have to shoot in live mode ie you focus not with the view finder but with the screen.
Summary: I would have seriously reconsidered this purchase. The idea of 800mm is a dream to have at such a price... especially for as short as it is. I had T-mounts for both Canon and Nikon so I could use on both... and I did. Same results on both. Clarity... fuzzy at best. Most of the pictures were very very dark even in the brightest of sunshine available. Tripod and mono-pod tested as well. I know that Rokinon has a decent product line... this one failed... MISERABLY!!
Summary: Really amazing how close you can actually get in on things. Even with a sturdy tripod outside, wind is a factor. So plan to provide some sort of shielding to guard against it. Image seems good.. the focus ring is really really (really!) sensitive... Will probably need to attach some kind of cantilever lever to it to give more precise focus control. Also, be sure to get the proper T adapter for your camera (obviously not included, but are only about $8-$10 on Amazon).
Excerpt: This is not an everyday casual lens. I bought this lens, because I was looking for a way to capture better detail of the moon without spending a small fortune. I have also used this lens to take pictures of distant skylines. For my special purposes, it's an incredible value. It's light, simple, and rugged (mostly metal). I use it with a Vixen 37301 T Ring adapter and a Nikon D800. Shooting with this lens is a process. The slightest vibration will blur the image.
Pros: Durable, Lightweight, Rugged, Strong Construction
Excerpt: Many reviewers noting the extreme difficulty in focusing this lens. I agree. I set up a tripod, used a shutter release in live view mode on my D800E and was never able to get an image that was better than acceptable. If you imagine using this for wildlife, you got a long row to hoe. I believe that with practice you could get to where some, probably not most of your shots are keeps if your threshold is not too high.