It makes me wonder why would Sigma create a constant f3.5 aperture lens if it is unusable at anything under f8? The Tokina is sharper at similar aperture and focal length settings, has less vignetting - even stopped down - and does not extend.

Sigma 10-20mm f/4-5.6 EX DC HSM Review - Trusted Reviews

as do all the other lenses in this comparison except the Sigma 8-16 which does not accept screw-in filters) and has a 2mm focal length advantage on the long end. Although I can't compare this to other UWA lenses I can compare it to other zoom lenses I have (such as Sigma 17-70) and this lens beats them hands down. Feel and build quality is excellent. HSM focussing is wonderful. Flare resistance is surprisingly good for a UWA. I love this lens and the perspective it allows. At f3.5 it has very good sharpness (at least in center) and I find f3.5 particularly useful for indoor shots or where you want a bit of bokeh on close ups (can only get so much on a UWA). Colours look nice too Shading or "vignetting" never gets real bad at the 10mm end, but then decreases relatively slowly as you stop down or zoom towards 20mm. The worst-case light falloff in the corners is only 0.7 EV, decreasing to just over 0.5 EV one stop down from wide open, for most focal lengths. Geometric distortion is quite interesting, in that the maximum level swings from pretty severe barrel distortion (1.3%) at 10mm to slight pincushion (0.29%) at 12mm, holding more or less constant at that level over the rest of the zoom range. What's really interesting though, is that the geometric distortion is almost entirely restricted to the very corners of the frame, so the average distortion level is actually very(!) low: Along the top and bottom of the frame, and along much of the left and right sides, the image is remarkably rectilinear. Sigma's optical engineers have done a very good job of compensating for distortion in the design of this lens! Most of my outdoor time with this lens has been on snow-covered ground and I am indeed seeing my corners go darker by a noticeable amount at common f/8 landscape apertures. Landscape photographers are of course one group that loves to find a close subject and frame it in a striking, vast, in-focus scene

Just behind the extended front element, there is a thin manual focusing ring, usable both in the autofocus (AF) and manual focus (MF) mode. For switching those modes, you must use DSLR internal menu, there is no mechanical button/switch. There a many other uses for ultra-wide angle lenses including architecture (especially interiors) and automobile photography.

Sigma 10-20mm f/3.5 EX DC HSM - Digital Cameras, Digital Sigma 10-20mm f/3.5 EX DC HSM - Digital Cameras, Digital

Canon's 10-22mm may be a comparatively old design (2004) but it still holds its own compared to the Sigma. While it doesn't offer a constant aperture, it's just as sharp and has a touch more telephoto distance to offer. CA tolerance is a bit better, distortion is about the same but there is a bit more corner shading. The lens extends a little when zooming. It's shortest at around 15 mm, slightly extended at 20 mm and at maximum length at 10 mm. The moving inner tube is very solid, there is no wobbling. The front lens does not rotate while focusing so using a polarizer is no problem. However, the front thread requires large (and expensive) 82 mm filters. Get the latest photography news straight to your inbox by signing up to our newsletter. Newsletter SignupI waited for this lens and finally entered the world of 10mm wide angle. I instantly fell in love and started using this lens as a walk-around lens. It's range of 10-20mm is much more useful than the Tokina 11-16 and the 3.5 is only marginally slower than the Tokina at 2.8, so I was pretty excited. The lens is very resistant to flare and ghosting, much better than the competitors. I compared it to various Nikon and Tokina super wide zooms.

Sigma EX 10-20mm f/3,5 DC HSM Review - Lensora Sigma EX 10-20mm f/3,5 DC HSM Review - Lensora

I compared performance and test images taken with the Sigma 10-20 f/3.5 against my Nikon 16-85 VRII, which I consider my sharpest lens. The photos were taken with a Nikon D5000, tripod mounted, no digital sharpening, of fixed targets on my living room wall at about six feet. The targets consisted of newspaper at the corners and a large US map in the center, with a variety of detail and some color. Illumination was provided by house lamps and a photo flood light. The images were compared side by side at 200% enlargement on my monitor. Typical of Sigma's EX line of lenses, this optic feels well put together and the fit and finish is excellent. Much of the lens barrel has a powder coating applied to it, which certainly looks the part when new. The section close to the the lens mount, which is different depending on the camera type it is meant to be fitted to, doesn't have the same powder coating on the sample provided for review. Although the finish on this section is acceptable, it looks a little odd next to the rest of the lens construction, as if Sigma decided not to coat this section for some reason or another.The overall shape of this lens is smooth with slightly smaller ribs on the focus ring than on the zoom ring. The Sigma 10-20 was not as sharp as the Nikon 16-85 in the very center of the image at comparable focal lengths (16mm and 20mm) and apertures, although was very close by f/5 and nearly the same at f/8. At the edges of the image however, the Sigma 10-20 was as sharp or sharper and had better contrast at f-stops tested, 3.5-8. I have no lenses to compare the Sigma 10-20 to at shorter focal lengths.

Sigma AF 10-20mm f/3.5 EX DC HSM - Review / Test Report Sigma AF 10-20mm f/3.5 EX DC HSM - Review / Test Report

A large, positive switch on the side of the lens barrel is used for changing the focus mode between auto and manual on Canon and Sigma mount variants. This is a heavier unit at 470g, with high construction values. The traditional Sigma EX finish doesn’t suit everyone’s taste, though I like its matt hammerite-like look. The rubber zoom and focus rings certainly feel secure, but there’s slightly more resistance in the zooming action than on competing models. The focus ring is slightly stiff too, though has a comforting dampened feel to it, making it feel very smooth. It isn't all roses though. You have be very careful about strong lightsources that may cause flare. This lens is easily prone to lens flare especially at night (and it isn't pretty when it does). I had a light source just left of my frame and the flare came in looking like water spots. Fortunately I could see them in my LCD viewfinder and I recomposed my image. Lenshood doesn't help much to combat this. The lenshood is pretty much pointless, and do be careful with it, for some reason the version I had was very loose and it was very easy to lose the hood in the reverse position. In the active position it wasn't so bad, but either way, it is a pointless accessory. We offer you to match any camera and lens to see if they are compatible or not. This is what the last users has tried to match. Canon EOS R100 + Sigma EX 12-24mm f/4,5-5,6 DG HSM though the center is sharp at all focal lengths and apertures it is almost useless at 10-12mm due to poor edge sharpness and very high lateral color starting about 30% out from the centersibling have the shortest focal length range aside from the Tokina 11-16, but the overall range differences are not great.