Home Sigma Lens Sigma AF 18-200mm f/3.5-6.3 DC OS Zoom Lens
Sigma AF 18-200mm f/3.5-6.3 DC OS (Optical Stabilizer) Zoom Lens for Nikon Digital SLR Cameras
I purchased this lens for use with a new Nikon D40 and have been blown away! I really enjoy having the flexibility to go from 18mm to 200mm in a single lens, rather than swapping between my 18-55 and 55-200 lenses. I took it for a "test drive" on a hike in the mountains this weekend, and I will never go back to carrying my two other lenses again when I'm walking around! Images were crisp and the colors were great. I forgot to take my circular polarizing filter with me, but it wasn't a problem with this beauty.

The optical quality is much better than I expected. There is some barrel distortion when you're zoomed back to wide angles - it was noticeable through the viewfinder. If it bothers you, it's corrected easily enough using Capture NX or Photoshop to work on your images.

The lens is noticeably heavier than its brethren, but I don't believe that will be an issue. It's also almost an inch bigger in diameter than my 55-200mm lens, but I actually think that's good. It feels better in my hand.

I found myself switching to manual focus on several occasions, as I was shooting through trees into the valley several miles from the mountain. As others have noted, the focus ring is larger than I have come to expect on other lenses, and I did find myself grabbing it by mistake a couple of times when I meant to go for the zoom ring. I'll learn, though...I'll be using this lens almost all the time, so I know I'll get used to it.

I have noted that in extreme close-ups (macro range), the lens does a great deal of "hunting" to find the right focus. The Nikon lenses often do the same thing, but the hunting is a little louder with the Sigma lens. I wonder if the wider lens barrel partially blocks the camera's autofocus sensor. Again, this is not a big issue for me...especially in macro shots, where I prefer to focus manually anyway.

The Optical Stabilization feature worked great. I didn't have a single blurred picture from my shoot on the hike, even though I was shooting at f10 or narrower most of the time, at many zoom angles, in a variety of lighting conditions, and without a tripod.

The biggest problem I had came from the embarrassment of riches at having so wide a zoom range available to me! On many occasions, I found myself shooting the same scene from the same spot, all the way from 18mm to high zooms, and every one of the pictures had its own artistic interest and merits. How do I choose which one I like best?!

All in all, this is a great lens. I'm very happy with it and I know I'll be doing a lot more photography with it than I would have been doing without it.