Very good for money, only budget ultrawide on FF, recomended.
7 June 2014
Summary: Original Nikon FF ultrawide 14mm 2.8 cost 1400$, this lens - about 325$. Most disadvantage is lack of AF, and some distorsion (can be fixed by software). AF not so critical on wide lenses but it most weak part of this rokinor/samyang/prooptic. Image qualty is good, its sharp even on f/2.8 and blade sharp on 4 and above. Focus ring very smoth - like nikon manual focus AI-s series. On my camera (d600) work all program mode (P,A,S,M), AF guide and AF confirm.
Summary: NOT AUTO-FOCUS, but great other-wise. Bought this lens for my Nikon D600 and I thought I read enough on it to understand everything I needed. I however misunderstood when it said it had a "chip" for Nikon cameras. That does not mean it auto-focuses, it just means it communicates with your camera about the lens settings. If you are not a person that is OK with manual focusing then don't bother with this lens.
Summary: This lens is about the best thing I have for my full frame DSLR's. On my crop frame cameras it is still a great wide angle and perfect for real estate which I use it almost every day. On a full frame it is 10 times better because of the larger sensor. This makes it much better for video and as a great alternative to a fisheye.
Summary: I could not be happier with this lens. I downloaded adobe's lens profile for it (Nikon D700 samyang 14mm f11) and the complex distortion is a thing of the past. This profile works pretty well with most full frame cameras. A friend of mine uses it with his 5DMk3. This lens is super sharp, even wide open. Coma is nearly nonexistent when shooting the stars at night. It reads f/2 in my camera, and the focus indicator works.
Summary: This is a great lens if you like to shoot manual. its a great rival to the Tokina 11-16mm, but obviously falls short of that lens in many features. but that lens will only cover full frame at 16mm. I put this lens on my 35mm camera and love the image. A great deal!