* 17 elements in 13 groups
* 110.5 to 71.6 angle of view
* 8 diaphragm blades
* Minimum focusing distance of 30cm at all focal lengths
* 1:6 maximum magnification
* 8.69cm (diameter) x 13cm (length)
* Weight: 600g
The lens has a solid feel, is somewhat large, but lightweight (a plus) considering its size. It has Sigma’s traditional black matte EX finish with the gold EX band around the focusing ring. The large, ribbed, rubber grip on both focusing and zoom rings, provide for responsive manual focusing and zooming. Also, the depth of field scale on the lens is for the 15 mm focal length.
The lens includes a non-removable petal shaped hood and a metal filter holder and lens cap protect the front element when the lens is not in use. The lens uses gelatin filters that insert in the rear of the lens. Screw in filters that attach to the front of the lens, can also be used, but only at the 30 mm focal length. At shorter focal lengths, severe vignetting will occur.
When closely focused on an object in the foreground, the extreme large angle of view of an ultra wide-angle lens, makes it possible to create dramatic landscapes that convey depth, since objects in the foreground appear larger than they really are in relation to the background. This is important to me in creating those 3-D like images in which a point of interest (such as a lizard, small mammal, or flowers), pops out in the foreground, with the background being used to depict its natural surroundings. When shooting at an ultra-wide angle, you can also capture landscapes with depth of field from the foreground of less than a foot to infinity, especially when using smaller apertures.
Given the many applications that an ultra-wide angle zoom will add to your photographic arsenal, the Sigma 15-30 f3.5-4.5 will simply stimulate your creativity. Its solid and durable construction, rich color saturation, and the versatility of the widest available zoom on the market will keep any working professional or serious hobbyist satisfied.
