Rokinon 20mm f/1.8 ED AS UMC Lens for Canon EF

When I switched from Nikon to Pentax, I knew the one focal length I would have trouble covering is wide angle... Pentax simply doesn't have any full frame wides. The only viable option is the Pentax 15-30mm which is an exceptional lens, but it's expensive and doesn't take filters.

Tested on A7III.Decently sharp at the center, just a bit softer moving to the corners, and heavy vignetting at F1.8. At F2.8, center is razor sharp, extreme corners remain similarly soft to 1.8, and vignetting is much improved.

I purchased this lens specifically for taking pictures of the stars. Traveling to Maui and during the prime Milky Way viewing season. The performed excellent and I would highly recommend this lens!

Was searching for a high quality (Zeiss, Sigma Art) Prime Wide Angle (18-21mm) for Pentax K-1 with no luck. After reading good reviews, settled for Rokinon 20mm F1.8 (K-1 shows 1.7). Lens is well made, light weight and compact.

I bought this lens for wide field astrophotography. I finally tested it with some Milky Way shots this week. The lens is great. There were comments that the lens suffers at 1.8 and 2.0 so I shot at 2.8. I intend to test the more open apertures later.

When I first received this lens, I immediately checked for any optical de-centering, which seems to be a prevalent problem in other Rokinon/Samyang lenses. I was unable to detect any problem. I then compared it to my Canon 17-40mm f/4 zoom at 20mm. At wide open (f/1.8 vs.

Summary: This lens has good build quality and my copy has even performance across the frame. Sharpness is excellent in the center but falls off towards the edges, those with an A7r may want to look elsewhere. The lens is good for astro at about f/2.8 and makes a good all-around landscape lens.

I shoot with a Sony A7R2. There's no live view with this lens. And there's a hair margin wherein to establish focus on stars. Moreover "focus tracking" on the A7R2 only sort of works with stars.

I’ve recently upgraded from the a6000 + Samyang 12mm to an a7ii + this Rokinon 20mm (I shoot mostly landscape but initially got into shooting because of my interest in astrophotography - thanks lonelyspeck!!!

Good lens for the cost.