Sigma Corporation is pleased to announce the launch of the new 18-125mm F3.5-5.6 DC. This zoom lens was exclusively designed for use with digital Single-Lens Reflex (SLR) cameras and has 6.9 times high magnification zoom ratio. Image circle is designed to match the size of the image sensor of digital SLR cameras. A Special Low Dispersion (SLD) and two pieces of aspherical glass elements produce high level of optical performance through the entire zoom range and also this has resulted in a compact, lightweight lens. This lens has a minimum focusing distance of 50cm (19.6in.) at all focal lengths and equipped with inner focusing system. Since the front of the lens does not rotate, "Petal Shaped Hood" and a circular polarizing filter can be easily attached and used. This lens is also equipped with "Zoom Lock Switch" that eliminates "Zoom Creep."
An image sensor element larger than those corresponding to APS-C cannot be used in digital cameras or 35mm SLR cameras. If such an element is used vignetting will occur on the picture surface.
Aspherical lenses Lens elements that are not spherical can reduce the total number of elements required in a lens design. They can deliver better performance while reducing weight and size.
Aspherical lenses maximize optical performance while minimizing lens size and weight. Aspherical lenses help reduce some of the problems usually associated with wide angles and zooms, such as lens flare and edge distortion.
They also help deliver higher quality telephoto images.
Internal Focusing For our mid-range lenses, we use an internal focusing system that moves inner lens groups to allow a shorter minimum focusing distance. All while retaining a constant physical lens barrel length.
I have acquired a collection of highly regarded lenses. Some of them are prime lens but even the zooms have relatively short zoom range - typically less than 3X. Therefore, they are not convenient as walk around lenses. I have been looking for a walk around lens for causal situations but one that covers large zoom range. I finally settled on this Sigma 18-125 because of the larger zoom range. I am still nervous of those 10X superzooms. Furthermore, the max aperture at the long end is still a manageable f/5.6.Optical performance is actually better than I can expect for the price. It is no comparison to the Tamron 17-50 f/2.8 or the Pentax 50-135 f/2.8 in terms of sharpness and resolving power. Comparing to the Sigma 70-300, the 18-125 is comparable but just a little weaker. BTW, the Sigma 70-300 is incredibly sharp. But for what I need it for, it is more than acceptable. Also, don't expect to have a soft out-of-focus background either, the aperture is too small for that.Construction is very good, far better than the Sigma 70-300. It is quite compact when zoom back to 18 mm. The lens hood is only borderline useful. It is small compared to that of the Tamron 17-50. I have not pushed the limit on flare control but I have a feeling it is not in the same league as the others.Sigma HSM is very nice and quiet. Focus is fast and accurate. It is definitely faster than the SDM in Pentax 50-135.My main complaint is the direction of zoom ring, it is opposite to every zoom I have.This is a good walk around lens. I would buy it again. I only wish the aperture is just a little larger at the long end. I guess I would have to pay a lot more for that.
Back To Top
