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

I love this lens. It's so easy to focus for landscapes and doesn't nudge easily which is a plus. I used it once for astrophotography and it performed excellently. I stopped down to 2.2 for less coma on the edges. Sunsets are stunning as well. It's a keeper!

I found this lens to a big surprise. It is very sharp. I take Astro photo and at f1.8 it is very good for the stars. It also is amazing for 4 grounds when like painting. F5.6 f8 are Sigma like sharp. I'm seem us this lens alot . Ibhave a Rokinon sp 14 F2.4 which is also amazing but the 20mm focal lengths I like better . No distortion stall. I'm very happy with this products. No regrets.

Great in low light. Easy to use. It doesn™t feel like the more expensive lenses, but it seems to get the job done for the price. Check your focus, no auto here

This is my first Rokinon lens for a Nikon camera. I have two Rokinon lenses for my Sony cameras and I am very pleased with them. I purchased the Rokinon 20mm for interiors. I wanted a wide angle lens on my full frame Nikon D800 and decided after much thought about what I wanted a lens to produce to go with 20mm. I had a 24mm “ 85mm Nikkor and like it very much, but I wanted a lens to give a wider field of view for interiors but not so wide to exaggerate (or distort) the scene. I am very pleased with the lens quality and the images it produces. In the same scene, I compared images taken with it to the Nikkor 24-85 and also to my Canon lenses and found the Rokinon to be sharp and to have little to no distortion, just like the other lenses. For interiors I like the manual focus and a prime lens. I can set focus to where I want it and the focus remains set correctly throughout the house I am shooting except for small rooms, where I refocus. I blend my images so having a prime lens that stays put is preferred because any movement in focal length just causes extra work in post. For the Nikon mount, I like that I can set the aperture ring to f/22 and then adjust the aperture with my camera; this is a nice feature. In short and in my opinion, the Nikkor 24-85mm lens does not outperform the Rokinon lens and neither does my wide angle Canon lens. For an affordable price, the Rokinon 20mm lens gives me images that are deliverable and that is what counts. With 40 years of experience in photography I can say I am so far very well pleased with the Rokinon lenses I own.

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. At F4.0, most of frame is razor sharp, extreme corners are much improved and vignetting is more or less gone. It continues to improve all the way to F11 where diffraction sets in, and we know the rest of the story. I like the lens optically except for the heavy vignetting wide open, but the lens is too. flipping. bulky. Its bigger and heavier than the Sony 85mm 1.8 and really just kills the point of having a mirrorless to begin with. Im going back to the Rokinon 12mm F2.0 on my A6300 if I need to go wide for landscapes or astro.

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. f/4), the corner sharpness, though not particularly sharp, was better than the zoom. Central sharpness was not dramatically different. When compared at f/4, the Rokinon was clearly better, especially in the corners; but the Canon zoom still put up a good performance except for the extreme corners. While I didn't do a lot of comparisons at smaller apertures, I'd would say it seemed to be pretty much a horse race. Finally, despite a common complaint about the inaccurate infinity setting in other Rokinon lens, this 20mm lens seemed spot on. Now for the caveat. On both my Canon 5D MKII and Canon 5Ds, metering was not accurate. It tended to overexpose at smaller apertures and increasingly underexpose when increasing the aperture (although that behavior wasn't exactly linear). The behavior was the same in either Manual or Aperture Preferred. I found a few similar complaints on the web; but since this is a relatively new lens, there isn't much user experience out there. Also, this may only be a Canon issue. The only theory I can concoct is maybe the metering algorithm, lacking the actual f-number, gets a bit befuddled regardless that it should only care about the actual light entering. I bought this lens only for astrophotography, so the exposure issue doesn't matter to me. For that purpose, I give it a 4-star rating (less one star for the exposure issue). For general photography, the lack of autofocus and potentially an exposure issue, I recommend you spend the extra bucks for a fully automatic lens.

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!

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. It's a little too big on mirrorless but the lens makes up for it with a great overall performance. I've been in the market for an UWA landscape lens that can double as an astro lens and decided to give this one a try. This was the last lens on my short list of more affordable options, had I not liked this one I would have been looking at Zeiss. I'd like to briefly go over expectations with this lens. The MTF charts posted on Samyang's website for this lens show that it's decently sharp wide open with some astigmatism at the corners. When stopped down the lens does sharpen up but the astigmatism doesn't improve much. This results in softness at the corners stopped down as well as 'wing-tip' aberrations on high-contrast points of light at wide apertures. The 'wing-tip' aberrations disappear when the lens is slightly stopped down. The copy I received has very even performance across the frame and its performance reflects its MTF charts. I was surprised with this as Rokinon/Samyang has a history of making lenses with wild variations in optical performance. A common example is their 14mm 2.8 which has the potential for amazing resolution based on its MTF but because of high build variance it usually falls short of those claims. Of course I could have gotten lucky but I haven't read any reports of high variance with this one. Wide open the lens is very good in the center with the mid-frame and corners falling behind. Stop down to f/2.8 for an increase in contrast and sharpness. It's at this aperture that corner aberrations clear up enough for astro. Stopping down further increases sharpness across the frame but the corners never resolve razor sharp like the center/midframe does, they're at their best at f/8 - f/11. If you use 24mp A7 or 12mp A7s it won't be a huge deal, the softness is only slight and won't ruin a picture. If you're using an A7r you may not like how this lens performs and should instead consider a Zeiss option. Handling and overall build quality is great, though the size could have been smaller. I understand this is a DSLR lens with an E-Mount adapter slapped on but Samyang/Rokinon should consider making a compact line of lenses with a short flange distance for mirrorless. The infinity focus stop seems to be exact or close enough. Overall image rendering is about average - this lens won't blow you away with 3D-like images that Zeiss lenses render but it can produce some nice color. It has a good close-focus distance but it needs to be stopped down to get good sharpness at MFD. Veiling flare resistance is good while ghosting resistance is only OK - it's possible to provoke a small rainbow ghost with the sun in the frame. Sunstars are 14-pointed and are defined by f/11.