Sigma 24mm f1.8 EX DG Aspherical Macro is one of the EX Series lenses. This lens has a fast F1.8 maximum aperture with macro focusing capability of minimum focusing down to 18cm/7.1inches (reproduction ratio 1:2.7). The iris diaphragm has 9 diaphragm blades to obtain beautiful out of focus image. It incorporates the floating focus system and uses two aspherical lens elements for minimizing distortion and spherical aberration and astigmatism. Internal focus system eliminates front lens rotation, thus allowing the use of a Perfect Hood and the easy use of polarizing filters. The lens incorporates non-vignetting optical construction, in order to obtain adequate peripheral brightness even at open aperture. This is desirable for digital cameras. The lens also incorporates dual-focus mechanism. It is easy to hold the lens, since focusing ring does not rotate during auto-focus, and yet it provides adequate focusing torque of the focusing ring during manual focusing of the lens. The lens materials used in this lens are lead and arsenic free ecological glass.
The Sigma 432-109 24mm f1.8 EX DG Aspherical Macro Lens for SLR Cameras has a super multi-coating that reduces flare and ghosting that tends to occur when using digital SLR cameras. The Sigma EX DG is a large-aperture, wide-angle lens for close up photography.
This large-aperture wide-angle lens is equipped with macro focusing capability down to a minimum of 18 centimeters, or f1.8 aperture speed, which provides a reproduction ratio of 1:2.7. The use of two aspherical lens elements in a floating focus system minimizes distortion, spherical aberration and astigmatism, which provides high performance at all shooting distances, as well as superior peripheral brightness. This 24-millimeter lens has an angle of view of 84.1 degrees, which allows the capturing of high-quality images not only of your subject, but of the surrounding scenery. Not only does the advanced optical construction of this lens enable it to receive adequate peripheral brightness at open aperture, but the iris diaphragm has 9 diaphragm blades that allow it to obtain beautiful out-of-focus images in the foreground and background. For handling, this lens also incorporates a Dual-Focus (DF) mechanism that makes it easy to hold the lens, since the focusing ring does not rotate during auto-focus, yet it still provides adequate focusing torque for the focusing ring during manual focusing of the lens. This has the added benefit of allowing the use of a Petal-type hood, which is superior in its light-blocking effect.
The Sigma 432-109 macro lens is constructed with 10 elements in nine groups of diaphragm blades, and has a minimum aperture of f22. This lens allows filters that are 77-millimters in diameter, weighs 17.1 ounces, and measures 3.3 x 3.2 inches (Diameter x Length). This lens is compatible with Sigma, Canon, Nikon (D), Minolta (D), and Pentax cameras with corresponding AF mounts.