Sigma AF-Zoom 70-300mm f/4-5.6 APO Macro

This is Sigma's consumer grade telephoto zoom which was introduced early 1995. I think is only a slight modification, mainly for the D-compatibility, of an earlier version: 75-300/4-5.6 APO. Note that there is different (cheaper) version without the APO designation. APO stands for apochromatic correction to reduce the color infringement at image corners. I keep this lens as a compact and light-weight 300mm lens, while praying for Nikon's 300/4 or 400/5.6 to become affordable.

The specifications include:

Mechanical construction is quite awful, with every movable part wobbles quite a bit. Its plastic feels cheap, although the rubberized finish (called "Zen finish") feel good and yet sometimes sticky. The macro switch is fiddly, and often needs several trials to set or unset it. When fully zoomed out, the lens doubles its length. But the extending part is light-weighted part, so the balance is kept quite well, just looks plain ugly: for a telephoto lens the front end is smaller than the rear end! The zoom ring is well frictioned but sometimes too rigid. Manual focusing feel OK albeit loose. AF is noisy and quite slow (due to its long throw). So far I don't have any electronic compatibility problem with either N90s or N6006 camera.

I found that the optical quality of this lens is very decent in most of its optical aspects. APO has indeed has achieved what it claims. And, one neat feature is its macros capability at the 300mm end, which can achieve a 1:2 magnification, and continuously AF-able. But I haven't yet utilized this feature since most of time I prefer to bring the Nikkor with me.

I did a test comparing this lens with Nikkor AF-Zoom ED 80-200. My observations are: Color is slightly cooler (slightly toward greenish) than the Nikkor. Contrast is also slightly lower, but not very noticeable. Color saturation is excellent. Center sharpness is well comparable, except at the short end, to the Nikkor and is very even through out apertures. Corners are soft, and improves only when well stopped down, such as f/16 marked. Almost unnoticeable light fall-off at wide open. Almost unnoticeable pincushion type distortion.

This lens does not perform well with TCs as the corners becomes unacceptable. Also, the lens wobbles quite a bit when fully zoomed, which is OK when used by itself, but becomes a serious alignment problem when used with TC. I've observed that one of the corners, not the center, has the sharpest image.

My conclusion: a decent cheap lens with fine optics. Also quite a neat 300 f/5.6 poor man' long macro lens. Well worth the money, but needs a good care.

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Last updated: July 18, 1997.