Sigma 20mm f1.8 EX DG Aspherical RF is one of several EX Series lenses. It is the first 20mm Super wide-angle lens in the world with a large aperture of F1.8 and angle of view 94.5°. It has Macro focusing capability with a minimum focusing distance of 20cm/7.9inches (reproduction ratio 1:4). The iris diaphragm has 9 diaphragm blades to obtain beautiful out of focus image. It incorporates an aspherical lens element in the front as well as rear lens groups, to minimize distortion, spherical aberration and astigmatism. The lens has non-vignetting optical construction, in order to obtain adequate peripheral brightness with open aperture. This is especially desirable for digital cameras. The lens incorporates a rear focus system eliminating front lens rotation, thus allowing the use of a Perfect Hood and easy use of polarizing filters. The lens also incorporates dual-focus mechanism. It is easy to hold the lens, since the focusing ring does not rotate during auto-focus, yet it provides adequate focusing torque of the focusing ring during manual focusing of the lens. The lens materials used in this new lens are lead and arsenic free ecological glass.
Sigma 20mm f1.8 EX DG Aspherical RF is one of several EX Series lenses. It is the first 20mm Super wide-angle lens in the world with a large aperture of F1.8 and angle of view 94.5°. It has Macro focusing capability with a minimum focusing distance of 20cm/7.9inches (reproduction ratio 1:4). The iris diaphragm has 9 diaphragm blades to obtain beautiful out of focus image. It incorporates an aspherical lens element in the front as well as rear lens groups, to minimize distortion, spherical aberration and astigmatism. The lens has non-vignetting optical construction, in order to obtain adequate peripheral brightness with open aperture. This is especially desirable for digital cameras. The lens incorporates a rear focus system eliminating front lens rotation, thus allowing the use of a Perfect Hood and easy use of polarizing filters. The lens also incorporates dual-focus mechanism. It is easy to hold the lens, since the focusing ring does not rotate during auto-focus, yet it provides adequate focusing torque of the focusing ring during manual focusing of the lens. The lens materials used in this new lens are lead and arsenic free ecological glass.
Sigma 20mm f1.8 EX DG Aspherical RF is one of several EX Series lenses. It is the first 20mm Super wide-angle lens in the world with a large aperture of F1.8 and angle of view 94.5°. It has Macro focusing capability with a minimum focusing distance of 20cm/7.9inches (reproduction ratio 1:4). The iris diaphragm has 9 diaphragm blades to obtain beautiful out of focus image. It incorporates an aspherical lens element in the front as well as rear lens groups, to minimize distortion, spherical aberration and astigmatism. The lens has non-vignetting optical construction, in order to obtain adequate peripheral brightness with open aperture. This is especially desirable for digital cameras. The lens incorporates a rear focus system eliminating front lens rotation, thus allowing the use of a Perfect Hood and easy use of polarizing filters. The lens also incorporates dual-focus mechanism. It is easy to hold the lens, since the focusing ring does not rotate during auto-focus, yet it provides adequate focusing torque of the focusing ring during manual focusing of the lens. The lens materials used in this new lens are lead and arsenic free ecological glass.
Sigma 20mm f1.8 EX DG Aspherical RF is one of several EX Series lenses. It is the first 20mm Super wide-angle lens in the world with a large aperture of F1.8 and angle of view 94.5°. It has Macro focusing capability with a minimum focusing distance of 20cm/7.9inches (reproduction ratio 1:4). The iris diaphragm has 9 diaphragm blades to obtain beautiful out of focus image. It incorporates an aspherical lens element in the front as well as rear lens groups, to minimize distortion, spherical aberration and astigmatism. The lens has non-vignetting optical construction, in order to obtain adequate peripheral brightness with open aperture. This is especially desirable for digital cameras. The lens incorporates a rear focus system eliminating front lens rotation, thus allowing the use of a Perfect Hood and easy use of polarizing filters. The lens also incorporates dual-focus mechanism. It is easy to hold the lens, since the focusing ring does not rotate during auto-focus, yet it provides adequate focusing torque of the focusing ring during manual focusing of the lens. The lens materials used in this new lens are lead and arsenic free ecological glass.
Last updated at 06/29/2026 21:21:15
Sigma 20mm f1.8 EX DG - Lens
Delivery $59
Sigma 20mm F/1.8 Ex Dg Rf Aspherical Wide Angle Prime Lens For Canon
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Sigma 20mm F1.8 Ex Dg Wide-angle Prime Lens For Nikon W/front And Rear
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Sigma 20mm F1.8 EX DG Aspherical RF Lens
Delivery $15.90
originally posted on adorama.com
This is another Sigma fast wide angle prime. I also own the 30mm and 50mm f1.4 and this has a very pleasing bokeh as well as just the right sharpness for portraits. I think the sharpness at 1.8, while not the razor sharp you'd want for a macro, is just the right sharpness for people. It is large and heavy and requires an 82mm filter but I don't consider those shortfalls, just artifacts of the design.A nice feature is that it focuses down to 6.5" which is great for getting those in your face non-flattering shots :)It doesn't have HSM but it focuses nice and fast on my D90.I have never experienced focus problems with any of my six sigma lenses and would not hesitate to buy Sigma again.
originally posted on adorama.com
I really can't think of anything good to say about this lens. After much research I decided to buy this lens. I saw a few reviews that said it was blurry, but there were considerably more good reviews. I tried the lens in a very well lit situation and it appeared to be crisp and clean on my LCD. When I downloaded the images to my computer and looked at the print size of the images they were all soft and blurry. Details like lips and eyes were undefined.The other thing I noticed was the lens had issues in auto focus, it wouldn't pick-up certain focal points and would keep searching for focal points. I should mention I am a professional photographer that has worked with a few good lenses and if you are a professional this lens will not be good enough. Stick with ... MoreI really can't think of anything good to say about this lens. After much research I decided to buy this lens. I saw a few reviews that said it was blurry, but there were considerably more good reviews. I tried the lens in a very well lit situation and it appeared to be crisp and clean on my LCD. When I downloaded the images to my computer and looked at the print size of the images they were all soft and blurry. Details like lips and eyes were undefined.The other thing I noticed was the lens had issues in auto focus, it wouldn't pick-up certain focal points and would keep searching for focal points. I should mention I am a professional photographer that has worked with a few good lenses and if you are a professional this lens will not be good enough. Stick with Canon their lenses were designed for their focusing system. I agree they are way over-priced, but I suppose that its worth it in the long run!
originally posted on ebay.com
Bought this lens for astro photography because of its' speed however the extreme coma, particularly towards the edges of the frame, made it totally unusable. This may have been a damaged example as it also showed symptoms of misaligned lens elements.
Sigma 20mm f1.8 EX DG - Lens
Delivery $59
Sigma 20mm F/1.8 Ex Dg Rf Aspherical Wide Angle Prime Lens For Canon
Free delivery
Affiliate Disclosure: We may receive a small commission for purchases made through this link at no extra cost to you. This helps support our site. Thank you!
Sigma 20mm F1.8 Ex Dg Wide-angle Prime Lens For Nikon W/front And Rear
Free delivery
Affiliate Disclosure: We may receive a small commission for purchases made through this link at no extra cost to you. This helps support our site. Thank you!
Sigma 20mm F1.8 EX DG Aspherical RF Lens
Delivery $15.90
This is another Sigma fast wide angle prime. I also own the 30mm and 50mm f1.4 and this has a very pleasing bokeh as well as just the right sharpness for portraits. I think the sharpness at 1.8, while not the razor sharp you'd want for a macro, is just the right sharpness for people. It is large and heavy and requires an 82mm filter but I don't consider those shortfalls, just artifacts of the design.A nice feature is that it focuses down to 6.5" which is great for getting those in your face non-flattering shots :)It doesn't have HSM but it focuses nice and fast on my D90.I have never experienced focus problems with any of my six sigma lenses and would not hesitate to buy Sigma again.
I really can't think of anything good to say about this lens. After much research I decided to buy this lens. I saw a few reviews that said it was blurry, but there were considerably more good reviews. I tried the lens in a very well lit situation and it appeared to be crisp and clean on my LCD. When I downloaded the images to my computer and looked at the print size of the images they were all soft and blurry. Details like lips and eyes were undefined.The other thing I noticed was the lens had issues in auto focus, it wouldn't pick-up certain focal points and would keep searching for focal points. I should mention I am a professional photographer that has worked with a few good lenses and if you are a professional this lens will not be good enough. Stick with ... MoreI really can't think of anything good to say about this lens. After much research I decided to buy this lens. I saw a few reviews that said it was blurry, but there were considerably more good reviews. I tried the lens in a very well lit situation and it appeared to be crisp and clean on my LCD. When I downloaded the images to my computer and looked at the print size of the images they were all soft and blurry. Details like lips and eyes were undefined.The other thing I noticed was the lens had issues in auto focus, it wouldn't pick-up certain focal points and would keep searching for focal points. I should mention I am a professional photographer that has worked with a few good lenses and if you are a professional this lens will not be good enough. Stick with Canon their lenses were designed for their focusing system. I agree they are way over-priced, but I suppose that its worth it in the long run!
Bought this lens for astro photography because of its' speed however the extreme coma, particularly towards the edges of the frame, made it totally unusable. This may have been a damaged example as it also showed symptoms of misaligned lens elements.
Compared to the previous review, I have been using this lens in a professional capacity for years. This is how I use it:• Wide open (F1.8) is not great, however at F2 for close focusing - AMAZING• F10 + Polariser in bright sunlight for amazing colour reproduction• Set this lens to F5 and above for ultra sharp imagesRule I go with is that if the subject I am shooting is close to you then anything below F5 - F2 is ideal, incredible DOF!
Amazing lens with great sigma quality, great bokeh and very fast autofocus. Fits Canon EF and EF-S. Very clear and sharp images for wide portrait with bokeh background!
Very Sharp lens at the optimal apetures f/8-f/16 very good at f/7 f/5.6, good at f/4...a bit soft at f/1.8-f/2.8 and f/22, better at f/3/5-f/4. It's a heavy big lens solidly built but does the job. Works using infrared with no to min. hot spot when shooting towards the light source. Good close up feature with manual override switch and large focus ring.
I'm very pleased with this prime lens after the first two months. It's been terrific for shooting in low-light without a flash, and even hand-held shots under those conditions come out nice and sharp. I am also very pleased with the boka. The only potential downside -- you can forget about using your built-in flash with this lens, because it's so broad you get that ugly arc shadow in your frame. But like I said, the great thing is you can shoot natural light even in very dim conditions. I also got some lovely video with this lens on my Canon EOS 7D.
I already own and use a heck of a lot Nikon's pro 17-35mm D lens, which is only 1.5 stops slower and whose quality is not even bettered by Nikon's own 20mm f2.8 D. So, why should I bother with this Sigma?Firstly, the 17-35mm has already been repaired/refurbished once and is old. And very heavy. I'm semi-pro and where I've had a kit that extends down to my superb 24-70mm f2.8 (another Sigma, the HSM model), I used to slip in my pocket an even older Tamron 17mm f3.5, which uses the old adaptall 2 system, and is manual focus only. The quality of the Tamron is rubbish wider than f5.6, but then on, is as good as the Nikkor 17-35mm.So, this Sigma 20mm f1.8 is also a bit rubbish at f1.8, particularly contrast. By f2.8 it's better and f4 is good (see my 1st image) and ... MoreI already own and use a heck of a lot Nikon's pro 17-35mm D lens, which is only 1.5 stops slower and whose quality is not even bettered by Nikon's own 20mm f2.8 D. So, why should I bother with this Sigma?Firstly, the 17-35mm has already been repaired/refurbished once and is old. And very heavy. I'm semi-pro and where I've had a kit that extends down to my superb 24-70mm f2.8 (another Sigma, the HSM model), I used to slip in my pocket an even older Tamron 17mm f3.5, which uses the old adaptall 2 system, and is manual focus only. The quality of the Tamron is rubbish wider than f5.6, but then on, is as good as the Nikkor 17-35mm.So, this Sigma 20mm f1.8 is also a bit rubbish at f1.8, particularly contrast. By f2.8 it's better and f4 is good (see my 1st image) and from then on, is contrasty and sharp, not better than the 17-35mm, but then, almost nothing else is! Another image I've added was taken on DX Nikon D7000 handheld at night, at f1.8. On the DX, it's equivalent to a 30mm f1.8; still a very useful spec.Unlike the lead-weight of my all metal tank-proof 17-35, the Sigma is plastic, apart from the metal mount and glass elements, of course. This makes it a lot lighter, though its dimensions are a lot bigger than my little Tamron 17mm f3.5. The 20mm f1.8 takes giant 82mm filters, which are costly and its decent lenshood has some effect reducing stray light and flare, but with that wide frontal area it is rather prone to ghosting and the multicoating is in another, lower league than the Nikon. However, careful placing of the sun behind trees and such and it does OK and stopping down helps, too.The auto-focussing is good and fairly quiet and accurate (some Sigma's back-focus, but mine's fine) but it's too old to include their hypersonic drive system (HSM). Having said that, the barrel does not rotate and the lens elements are light so they don't need much time or energy to focus from infinity through to the minimum 0.2m. This might seem a gimmick, but is great for environmental portraits - a single flower in a wide landscape, for example. One can get so close, in fact, that the petal-shaped lenshood often casts a shadow on the subject! The lens also uses a rather odd push/pull M/F to A/F mechanism, which takes some getting used to but is in effect no worse than a fiddly button somewhere. At least this falls easily to hand, unlike those switches on other lenses.Barrel distortion is low, to the point of it not being noticeable, making it a good choice for architecture. Photoshop CS distortion filters include settings for this lens and when employed, has little effect, showing the quality of the original. I expected much worse vignetting from this lens, too, especially at very wide apertures and at its FX 92 degrees angle of view, though I haven't tested it yet but it's not obvious in the viewfinder, which again, is a pleasant surprise.My main uses will be for band and music festival photography, where I want an occasional ultrawideangle but want a lighter kit load. It would be asking too much to ask it to perform superbly at f1.8, but it could get you an image at least and which might sharpen up afterward. The fact that it's fully usuable for professional use from f3.5/f4 is encouraging and I look forward to using it regularly.
This lens supposedly has great optics. Unfortunately, I never got to use it because it does not work on the Nikon D7000. Google it, and you'll see for yourself. When you attach the lens, the metering cuts in and out, and the AF will not work. I quaduple-checked all my settings, on both lens and camera, and no dice. Apparently, it's a Sigma firmware issue - you have to send the lens to Sigma in Japan for a firmware upgrade, and it takes weeks. [...] Really disappointing, as nobody else makes wide, fast lens for an affordable price.
I shoot on a nikon d800 and I used the nikon 20mm 2.8 for over a year in nightclubs and music festivals.I bought the sigma for the sole reason of having a larger aperture, however, the image quality on the sigma is FAR better than the nikon.Build quality is a little plasticy but that's too be expected these days, it's not "too" plasticy by any means. Focus ring is smooth and buttery, bokeh, amazing, image quality, sharp. All around great and better than the nikon!Autofocus is "normally" fast, nothing amazing or slow about it. Highly reccomend this over the nikon.
