Sigma 18-50mm f/2.8 EX DC HSM Macro Lens

Sigma 18-50mm f/2.8 EX DC HSM Macro Lens for Nikon DSLR
Large aperture zoom lens designed specially for use with digital SLR cameras with a minimum focusing distance of 20cm (7.9"). This lens is specially designed to suit the characteristics of digital SLR cameras and provides a high level of optical performance. It has a large aperture of F2.8 throughout the entire zoom range, offers superior peripheral brightness as well as a compact and lightweight construction. A maximum magnification of 1:3, making it ideal for close-up photography.

Customer Review: Fabulous lens if not for the front-focus and random overexposure problems...

I purchased this lens in spite of the possibility of receiving one of the "faulty" lenses I'd read about in other reviews. Unfortunately I seem to have bad luck.

I kept the lens for nearly a month, hoping it was my camera (I have a Nikon D40) but I tried it on a Nikon D200 and got the same disappointing results. If one were to merely glance at the photos, they would probably not notice anything wrong. But as I looked closely at almost every picture with a narrow depth of field (pictures taken wide open at f/2.8) the area in focus was just in front of the area that should have been in focus (in a portrait, the tip of the nose would be perfectly sharp but the eyes would be a little soft and blurry).

The other frustrating malfunction was a tendency to randomly grossly overexpose. This also occurred only when the lens was wide open.

Otherwise, this would have been an awesome lens and I'm sorry that it had these problems. I still managed to take some great pictures but it required that I compensate on every shot for the front-focus problem. Total bummer.

I finally decided to just return the lens today. I think I might try Tamron's version, or just purchase the Sigma lens in a local shop so that I can try it out first.

Customer Review: Issue with connectivity

I liked the photos I took with this lens. THe macro is just fantastic. After a week I started having problems when the camera would not fire and the display would show F-- . The lens metal connectors were not sitting right on the camera connectors. It had to be twisted a little to connect with the camera body connectors otherwise it would not fire. I returned it to Amazon.

Just to make sure I have no faulty camera body I tried the original Nikon lens and it works perfect.

PS: I used this on a Nikon D50