Sigma 20mm f/1.8 EX DF RF Aspherical Wide Angle Lens for Nikon SLR Cameras

Other products by Sigma  | See collection 

Product Details

• Item Weight: 3 pounds
• Shipping Weight: 2 pounds (View shipping rates and policies)
• Shipping: This item can only be shipped to the 48 contiguous states. We regret it cannot be shipped to APO/FPO, Hawaii, Alaska, or Puerto Rico.
• ASIN: B00005RKSL
• Item model number: B00005RKSL
• Average Customer Review: 4.5 out of 5 stars  See all reviews (20 customer reviews)
• Date first available at Amazon.com: November 1, 2001

Product Description

Amazon.com Product Description

The Sigma 20mm super-wide-angle lens provides minimal light falloff and superior peripheral brightness, helping you take masterful landscape shots or large family portraits. The lens is equipped with a high-quality Dual-Focus (DF) mechanism. The DF system makes it easy to hold the lens, as the focusing ring doesn't rotate during autofocus. At the same time, however, the lens still provides adequate torque for manual focusing operations. By incorporating a rear focusing system, Sigma made the lens compatible with petal-type hoods, which offer superior light blocking effects. In addition, the lens offers a super multi coating that reduces the flare and ghosting that often occurs in digital cameras, along with nine diaphragm blades to help you obtain beautiful out-of-focus images in the foreground and background. Other features include a minimum focusing distance of 7.9 inches, a maximum magnification ratio of 1:4, aspherical lens elements in the front and rear lens groups to compensate for distortion and spherical aberration, and a 94.5-degree angle of view.

Specifications

• Focal length: 20mm
• Maximum aperture: f/1.8
• Lens construction: 13 elements in 11 groups
• Angle of view: 94.5 degrees
• Number of diaphragm blades: 9
• Minimum aperture: f/22
• Minimum focusing distance: 7.9 inches
• Maximum magnification: 1:4
• Filter size: 82mm
• Mount: Nikon
• Dimensions: 3.5 inches in diameter and 3.5 inches long
• Weight: 18.3 ounces
• Warranty: 1 year

Product Description

This super-wide-angle lens is ensured minimal light-fall-off with superior peripheral brightness. The iris diaphragm has 9 diaphragm blades to obtain beautiful out of focus images in the foreground and background. This is an ideal DG lens optimized Digital SLR camera.The minimum focusing distance of this lens is 20cm (7.9 inch) and it has maximum magnification of 1: 4 with fast F 1.8 maximum aperture. The minimum focusing distance of 20cm (7.9 inch) and 94.5? angle of view allow close up photography surrounding the photographic subject.The lens incorporates Dual-Focus (DF) 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 rear focus system eliminates the need for the front of the lens to rotate, thus allowing the use of a "Petal-type hood", which is superior light blocking effect.The use of aspherical lens elements in both of the front and rear lens groups effectively compensates for distortion, spherical aberration and astigmatism.

Customer Reviews

Most Helpful Customer Reviews

22 of 24 people found the following review helpful:

5.0 out of 5 stars AMAZINGLY SHARP AND FAST SUPER-WIDE ANGLE, May 7, 2006

By	GT "canon digital rocks" (N.O., LA United States) - See all my reviews

I have used this lens extensively with the 1D and the Rebel XT. Results have been excellent. My suspicion is that the previous reviewer got a defective or damaged copy of the lens. It is incredibly sharp, even at f1.8, which I did not expect - generally you expect a lens to be a bit soft wide open, especially 1.8. The degree of sharpness of this lens is quite surprising.

I have used, for example, both the Canon 50mm f1.8 and the Canon 35mm f2.0, both of which are deservedly renowned for their sharpness and contrast. I find this lens to be sharper than either of them wide open. The lens provides images which have excellent color saturation and contrast. Of course, at f1.8, depth of field is razor thin, by design, which is great for bokeh or out of focus background, but which also requires care concerning the desired focal point being in focus. Speaking of bokeh, I find it to be very attractive compared to any other lens I have used.

Its minimum distance focusing is also quite remarkable. I think it is rated at just under 8 inches, but I routinely focus at distances which seem a good bit closer than that. The lens works well as a macro for many applications, with a relatively strong multiplication factor.

Of course, given the inherent light-gathering of a 20mm focal length lens, combined with a huge aperture of f1.8, this lens is outstanding for shooting indoors or in other low-light situations with natural light and no flash.

Canon's nearest competitor to this lens is the 20mm f2.8, which is a full stop slower in terms of light collection. I consider this lens to be an extremely good value at the retail price, new. If you can get a good copy used on-line, it will be an incredible value. You may find that you never want to take the lens off the camera because of its versatility as a walkaround lens.

This lens has been extremely well-reviewed, by and large, on lens forum sites. I encourage you to check those out. Most people rate the lens 5 out of 5. A distinct minority give it 1 out of 5. I suspect that they either have defective copies which may need repair, or they have inaccurate perceptions of the lens. Also, popular photography magazine online reviewed this lens, as well as the 24 f1.8 and the 28 f1.8, very highly.

I would highly recommend this lens to anyone who wants a fast, sharp superwide angle lens.

11 of 11 people found the following review helpful:

5.0 out of 5 stars Wonderful!!!, January 8, 2007

By	Micah - See all my reviews

This is one of my all time favorite lenses. I usually just leave it mounted. It's fast max aperture and close focusing make it indispensable to me. Check it out--it focuses to within and inch of the front lens element!

I've had one issue-it recently self destructed. The iris folded over itself. It's inside the four year warranty (and damn near the end I might add) so it's been fixed and is currently on the way back to me from sigma as I type this. I'm disappointed it failed, but considering the frame count and price, I can't really complain.

I paid not much more than $300 for this lens new almost 4 years ago, and I'd gladly pay twice that for the shots this lens has gotten me. I've taken it out in the rain and snow and hail and the fact that it failed only recently attests to the build of this fine lens.

Buy it while they still make it! I may buy a backup soon for this reason.

8 of 8 people found the following review helpful:

5.0 out of 5 stars Ultra-wide lens with sharpest optics!, June 5, 2004

By	Denzil Thakur (Dubai, UAE) - See all my reviews

Sigma 20mm EX is an exceptionally well made lens. Performance is extremely satisfactory. It is almost indispensable for me to go without it when I am outdoors. Takes very good wide angle shots of buildings, parks and friends and family picnicking in the park. Shots have come very sharp and crisp with edge to edge brightness and sharpness. 20mm wide angle focal length gives you a very large depth of field which is essential for taking shots of wide open outdoors, filling your frame with a large expanse of ground/sky. Fast f1.8 aperture will let you take snaps indoors in natural light and hand-held shots of lighted buildings etc. in night time. Rear focusing feature of this lens results in fast AF and also the length of the lens remains same. Macro shots of subjects will give you convex mirror type of fascinating images and one can produce far more interesting effects depending on one's creativity.

Indoor flash photography may give rise to vignetting due to ultra wide nature of the lens as most flashes cover only 28mm span. This may probably be solved by using a wide angle attachment on the flash which to my disappointment was not available for my flash (Pentax AF-280T). Also 82mm filters may prove to be expensive. But I think a filter is essential for this lens as the front element glass is very near to the filter area.

All said this is an extremely satisfying buy (most bang for bucks) which gives you great results.