Buy Sigma 20mm f/1.8 EX DG RF Aspherical Wide Angle Lens for Canon Digital SLR CamerasSigma 20mm f/1.8 EX DG RF Aspherical Wide Angle Lens for Canon Digital SLR Cameras Product Description:
Product Description
The Sigma 20mm f/1.8 D EX DG Aspherical Lens has a clutch-like system for switch between AF and MF modes. The system is very similar to the Sigma 105mm f/2.8 EX macro lens I reviewed previously. You push the manual focus ring forward to disengage the focus ring for auto-focusing. For manual focusing, you pull it toward you to engage the clutch. When the ring is set to AF, you can rotate the focusing ring all you want, you won't change the focus on the lens. When the lens is auto-focusing, it also doesn't effect the position of the manual-focusing ring. The manual focus ring is wide so there is no chance that you'll miss it in operation.
Customer Reviews
Most helpful customer reviews
39 of 44 people found the following review helpful.
AMAZINGLY SHARP AND FAST SUPER-WIDE ANGLE
By Canon
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.
17 of 19 people found the following review helpful.Wonderful!!!
By Micah
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 an inch of the front lens element! [edit: re-checked and it's actually about 3" from the front element. For reference the Nikon 20/2.8 focuses about 9" and the 28/1.4 focuses about 11" from the end of the lens.]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. [edit: ok, maybe I can complain. It took them no less than five (5) tries to repair it properly. But in the end they did and I only had to pay the cost of shipping the first time. Works at least as good as new.]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.[edit: falling in love all over again! This thing rocks on my new d700!]
13 of 14 people found the following review helpful.Ultra-wide lens with sharpest optics!
By Denzil Thakur
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.
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More than adequate
Possibly useful for certain applications.