The Samyang 14mm f2.8 IF ED UMC Aspherical is produced in S. Korea and usually sold in the U.S. under brand names like Rokinon or Bower at budget price. The lens body has a small barrel topped with a huge bulb-like front element with built-in hood. It comes with a deep lens cap that slips over the hood securely.
It is a manual only lens, with no electronic or mechanical coupling to your camera body. Not only is focusing manual, the aperture must also be operated manually. Stopping down the aperture from f2.8 immediately closes the diaphragm and darkens the viewfinder. The proper way to operate the aperture is to focus at f2.8, then change to the desired shooting f-stop before taking a shot. This let the photographer obtain accurate focus with a bright viewfinder and shallow depth-of-field. I am lazy and usually leave the lens on the shooting f-stop, because focus is not critical with a 14mm lens.

PRO:
Very high resolution, both center and edge.
Relatively low CA, impressive for an ultra-wide angle lens.

CON:
All manual operation. No AF motor, no aperture motor. No electronic communication with the camera body. No f-stop or focal length information would be recorded in the EXIF.
Focusing scale goes beyond infinity. I have read some reviews stating that the marking for infinity does not correspond to true infinity focus. Fortunately for me, they do on my lens. Nevertheless, it is annoying not to have a physical stop at infinity. I cannot hyper-focus the lens without taking my eye away from the viewfinder.
Large barrel distortion with funny 3rd order mustache sub-frequency, enlarging the center like a blob while squeezing the edges. Fortunately, a 3rd party lens profile is available for ACR & Lightroom, making this lens usable for non-critical architectural photography. Ironically, I prefer correctable 3rd order distortion over pure 1st order barrel distortion. Less of the corners are cropped after correction, giving me the wide coverage I see in the viewfinder.

All samples shown here were shot on a full frame camera with distortion corrected in post-processing.
This lens was stolen on May 2016 along with my other gears. Since I also have the Canon 16-35 f4 LS, I have not replaced it. If I need to replace it, I will probably get the AE version that includes electronic interface and auto-diaphragm. Although the AE version is still manual focus only, I prefer its ability to record f-stop in EXIF.