Sigma 180mm f/3.5 Macro in Nikon Mount

Concept: 3 out of 5
Execution: 3 out of 5
Yeah, but: If at first you don't succeed...

The Long Version: Sigma makes five macro lenses, and they all have the "EX" rating marking them as the best they make. In Canada, that means a 10-year warranty and a 48-hour service commitment - if they have parts in stock. I ran into that qualifier with their 150mm Macro lens in 4/3 mount, which I started reviewing over a year ago. (Parts one and two). But despite my mixed experience with the 150 macro, I was still impressed enough with its optics to buy its big brother for my Nikon D700.

Compared to the 150mm 2.8 Macro, the 180/3.5 is longer and heavier, but has fewer lens elements. The 180 does have a slightly more impressive MTF chart, and a working distance that's 8cm/3" longer, but aside from that there really doesn't seem to be much difference between them. While I own both lenses, they're in different mounts and feeding very different sensors, so there's no point in a head-to-head comparison. That isn't going to stop me from wondering why Sigma has both lenses in its lineup, but until I get a chance to play stump-the-sales-rep, I don't think I'm going to have an answer for that question.

For what it's worth, and for the three people to whom this will matter, the 180 macro has an aperture ring while the 150 does not. Otherwise I'd say that you should pick the lens you need based on their size and working distance, since any difference in sharpness or brightness is going to be inconsequential in actual use. (amended three months later: now that I'm starting to understand just what a big deal micro-4/3 cameras are, the aperture ring may be the 180's unique selling point. Putting one of these lenses on a G1 or GH1, with their dense sensors and articulating screens - via an F-to-m4/3 adapter - would make an especially awesome macro setup. I'd suggest that Nikon users should look at the 180 instead of the 150mm simply for this potential, even if they don't yet think that a m4/3 camera is in their future.)

Complaints about poor sharpness are rarely heard about any macro lens, and the Sigma 180 is at the top of this particular category. I'm not going to dwell on it too heavily; I've used the lens on a solid tripod and have absolutely no complaints. The photo above is a reduced section - not 100%, but larger than I'd use - of the area that I magnified for manual focus, and was shot at f/16 with my D700. I find it completely acceptable. Naturally, depth of field is extremely shallow, which makes a single photo just a starting place for jewellery photography. After processing many photos shot at subtly different distances, the finished result looks something like this:

The image above is very nearly the entire frame, so it shows both the amount of magnification that the D700 gets at 1:1, and gives some sense of the size of the previous sample. If you're planning a macro kit from the ground up, don't assume that a bigger sensor is a better idea. A 1:1 ratio is reality:sensor, so a bigger sensor means capturing a bigger part of the world. A reduced-frame camera's smaller sensor with denser pixels makes for a powerful combination.

But just because a lens can focus on small things doesn't mean that it shouldn't get to photograph large things. At 180mm and f/3.5, the Sigma is a useful medium-to-long telephoto. Canon and Nikon both make 180mm and 200mm prime lenses, and they alternate between f/2.8 non-macro and slightly slower macro lenses. So there is a strong precedent for macro lenses and prime lenses in this focal range, and of course the plentiful 70-200mm lenses for both major manufacturers also speak to the focal length's suitability for all kinds of photography. Telephotos are easy to shoot with, flatter most subjects, and can give the subject/background separation that Serious Photographers want to prove that they weren't shooting with a Coolpix. While the Sigma 180mm Macro isn't a small lens, I do find it very useful for general photography.

Looking at my images taken with the 180/3.5, there's a fun little game that I play called "guess the aperture". I've gotten good enough that I can usually spot the difference in vignetting between f/4 and f/5.6, which are my two favourite apertures for hand-holding this lens. A crop-sensor camera will avoid most of this - which is why they were invented - but since I'm using a camera that uses the entire image circle, I'll be building some Lightroom presets to take care of the problem. For what it's worth, the image above is shot at f/4.0, and the photo below was taken at f/5.6.

The 150mm and 180mm macro lenses both use the same tripod collar. It was one of the highlights of my experience with the shorter lens, and it's just as good on the 180. Instead of being a solid collar that slips over the back of the lens, it's split with a hinge and secured by a cam-lock. This lets it unclip from the lens without taking it off of the camera, which is great for on-again, off-again monopod sessions. A lens this long without image stabilization really does benefit from the extra support, but it's also bright enough to get away with shooting hand-held when perfection is overkill. It's nice to have the choice.

People who have read my reviews of the Sigma 150mm in 4/3 (aka "Olympus") mount might be surprised that I haven't mentioned the autofocus on the Nikon-fit 180/3.5. That's because it's simply not an issue with this lens - it's certainly not the fastest, but it is very quiet and reliable. The photo above shows a bit of camera-shake blur and a bit more Jack Russel blur, but is the only time I was able to catch the dog in motion (as if there's another state for a JRT) with anything approaching presentable sharpness. This isn't an action-photography lens, but it would be fine for normal movement, which is far more than I can say for the Olympus-mount version that inspired me to buy this one.

The Sigma 180mm f/3.5 macro lens leaves me with no complaints, except for its vignetting, which is apparently something that's not unusual for full-frame sensors and the lenses that are designed for them. I'd prefer not to see it, but it can be fixed fairly easily. But I keep coming back to my earlier question about why Sigma has both a 180mm and a 150mm macro lens in its lineup. The longer working distance of the 180mm is nice, but for my product photography it isn't as important as it would be for nature and critters. Essentially, I bought the 180 size only because I already had the 150 in 4/3 mount, and even I can't bring myself to that level of techno-redundancy.

From what I know about the 150, and after using the 180, I'm left without any strong reason to recommend one over the other, but can endorse them both. Just try them out and see which one you like best.