Rokinon is a South Korean company which makes outstanding third-party lenses. I have been considering a wide angle lens for landscape work for some time, including wide angle lenses made by both Canon and Tamron in the 10-20mm range, but these are fairly expensive. In doing some research, I came across the Rokinon ultra wide 8mm fish eye. This lens is under $300 and has rave reviews everywhere you go on the internet. Being a fish eye lens, it grabs 180 degrees of the field of view, a range so huge that my feet often appear in a shot unless I'm certain to aim perfectly level. Its unbelievable. Fish eye lenses are limited in their use; the distortion they produce means you can't show these photos too often, or the novelty becomes trite. However, they produce very interesting results, and the more creative you can be, the more interesting the results of this very unique type of lens.
The Rokinon fish eye is a fully manual lens, so aperture and focus are set by the user, not by the camera. This brings the price down, but manual focus and aperture setting are the equivalent of driving a stick shift car over an automatic. You get a true feel for the lens in the operation of it. Your camera will meter light levels, so shooting on manual--which I do 99% of the time anyways--is the best way to use this lens.
I'm happy to report that the quality of the lens is outstanding. The barrel is solid, metal construction. The base of the lens is metal, not plastic, and the lens glass produces rich colors with remarkably little chromatic abberation. There is a permanent, built-on petal style lens hood to reduce sunlight glare. The manual adjustment focus ring is butter-smooth, and the overall feel in use of this lens is reminiscent of the solidly built Pentax manual Pentax lenses I learned photography on back in the early 80's.
When using this lens, I find that image sharpness improves once the aperture is above f/5.6, with the sweet spot being at f/8. This lens has few moving parts and elements. Owing to the lens length and the quality of the lens glass, depth of field--the area of acceptably sharp focus from the film plane/sensor to the subject--is very long. Regardless of settings, you are almost always guaranteed to have nothing less than sharp focus for the whole image. Good for landscape shots, but with this lens, you cannot do a portrait shot with your subject in sharp focus in the foreground and the background in soft focus. Its not that kind of design.
There is a focus guide ring on the lens barrel; if you're close to your subject, you twist the focusing ring to the left using the distance guide on the ring as a reference ; for subjects further than 3 feet away, you twist the focus ring to the right until the focus ring meets the infinity symbol. This lens produces sharp, clear images every time it seems, and if in doubt, just check the focus guide above the aperture ring.
The aperture ring must be set wide open at f3.5 when attaching the lens to the camera body. Once locked on, I generally set the aperture ring to f/8 for general landscapes. I dial the aperture up and down to balance the light levels, keeping my shutter speed above 1/60 at all times since there's no image stabilization on this lens.
Owing to the bulging front element glass, you cannot use filters, not even the larger P-sized filters handheld. The front element glass is just too huge. That said, the glass on this lens is such good quality, that sunny skies tend to be nice and blue as the eye sees them, as colors are very well-rendered.
This lens is a well-built product which is very reasonably priced. Fish eye lenses are a novelty in their way. They produce outlandish barrel distortion depending on how you shoot your subject. You have to be careful not to overdo things, but if used well, they can create some very interesting landscapes and portraits.
Pros: Solid construction, metal body, built-on petal lens hood, metal base, smooth-as-silk focus adjustment ring, clear focus and aperture number markings, low price, high quality.
Cons: Cheap lens cap. That's it, the only thing I can find fault with.
Conclusion: If you want a fish eye lens or an ultra wide angle, seriously consider this one. Hundreds and hundreds of dollars less expensive than the Canon and Tamron offerings. A very, very nice lens. I've added a few quick shots, with some non-fish eye shots for comparison. I'll add some more pictures as