Sigma 18-125 comes with the unique Optical Stabilizer function, which makes use of two sensors inside the lens. It will detect the horizontal and vertical movement from the camera, and then moves the optical image-stabilizing lens to compensate for the camera shake. With this system, the users will benefit from shutter speeds that are approximately 4 stops lower than usual. With the OS, it is possible for the users to capture subjects in motion.
The Sigma 18-125 lens has been designed to be used with APS-C digital SLR cameras. It comes with a light plastic construction that is similar to most kit lenses. The lens comes with a minimum focusing distance of 35 cm at all focal lengths and a magnification ratio of 1:3:8, making it a suitable choice for close up photography.
The SLD glass, the molded glass aspherical lens and two hybrid aspherical lenses will provide an excellent correction for different types of aberration. Just like the other types of lenses from Sigma, Sigma 18-125 comes with a super multi layer coating to prevent ghosts and flares so you will get high quality images on all ranges.
On the Sigma 18-125 lens, the telephoto part of the lens is tight and does not have any imprecision at all. It has a zoom lock, although it is not necessary since the lens does not creep in any way. The build of this lens is solid.
The Sigma 18-125 comes with a nice mechanical and optical performance. It is not only compact but also more suitable for the people who do not want to carry around a lot of lenses. The sharpness is good although the corners are soft. The users will also experience one major drawback – distortion. The lens comes with a visible barrel distortion especially at the wide ends of the zoom. Fortunately, they can reduce this by going a stop or two lower from the wide ends.
With Sigma 18-125, the users will be able to capture clear and sharp hand held shots. They will also benefit from the speed and quiet focusing mechanism on this lens. The shots they take in challenging situations will still look good and will be in focus.
While the users will enjoy the quality of this lens, it is important to note that it is a heavy lens. They will also need to be prepared to charge their camera often when using this Sigma 18-125 lens for more because it drains the battery life faster due to the OS mechanism.