Sigma's 180mm f/3.5 APO EX DG HSM Macro is the only lens in its macro range with an HSM autofocusing motor - but only on the Sigma, Nikon-D and Canon mounts. Designed for use on full frame digital SLR cameras, but can also be fitted to DSLRs with smaller APS-C size sensors, where it covers a similar field of view to a 270mm lens when fitted to Nikon, Pentax and Sony cameras with 1.5x crop factors or 288mm with Canon DSLRs.
Interestingly, this lens was shifted from the ‘current' to the ‘recently discontinued' product list on Sigma Corporation's website during the review period. (It appears to have been replaced by the 150mm F2.8 EX DG HSM Macro lens.) Nevertheless, we've decided to complete the review because product is likely to remain available for a while and some readers may consider buying the lens second-hand.
The Sigma 180mm f/3.5 APO EX DG HSM Macro lens shown with the tripod collar but without the supplied cylindrical lens hood. (Source: Sigma.)
Weighing 965 grams, this lens is a substantial handful containing13 elements arranged in 10 groups - a fair amount of glass. Two special low dispersion (SLD) glass elements have been included to minimise common aberrations and the design is optimised to keep spherical aberration and astigmatism at a minimum. As in most modern lenses, there's no dedicated aperture ring; settings are controlled electronically from the camera.
Build and Ergonomics
Like the 50mm and 105mm macro lenses we've reviewed recently, the 180mm macro lens has the EX (‘Excellence') matte finish on the lens barrel and supplied cylindrical hood and comes with the same DG (‘digital') coatings that minimise the effects of internal reflections off the surface of the sensor. It's significantly larger than the 105mm lens and has some features that lens lacks.
The front element is close to the front of the lens and recessed approximately 5 mm. A 73 mm wide focusing ring is located about 15 mm back. It carries a 46 mm wide ridged rubber grip that turns through a little more than 180 degrees as you go from the closest focus (0.46 metres) to infinity.
Autofocusing is driven by an HSM (Hyper-sonic) motor, which is fast and near-silent. Full-time manual focus over-ride makes it easy to swap between auto and manual focusing in one-shot AF mode.
Behind the focusing ring is a distance scale, which is recessed into the outer barrel beneath a transparent panel. It carries distances in metres and feet from infinity to 0.46 metres. Just aft of the distance scale and a little to its left is AF limiter slider with three positions. There are two limit positions - 0.46 to 0.61 metres and 0.61 metres to infinity plus a Full position that covers the entire range. The focus limiter only works in AF mode.
Unlike its shorter siblings, the 180mm lens also features a true internal focusing (IF) design, which means its length doesn't change with the focusing distance. Two moving lens groups are used for focusing, which means the front of the lens doesn't rotate, allowing use of angle-critical attachments like graduated filters and polarisers.
The 90 mm long cylindrical lens hood supplied with the 180mm lens attaches with a bayonet mount on the front of the barrel. It can be reversed over the barrel for storage or carrying. You can also fit the lens cap when the hood is in either position.
Also supplied with the lens is a removable tripod collar with a screw nut that enables the camera body to be rotated between horizontal and vertical positions without requiring the lens to be detached from the tripod. White reference marks on the lens barrel and tripod collar allow precise alignment.
Behind the tripod collar and close to the camera body is the AF/MF switch, which is also on the left side of the barrel when the lens is mounted. (This can be inconvenient when you wish to switch from AF to manual focusing when the lens is tripod-mounted and the camera is vertically orientated.)
Although the tripod collar, lens hood and front and end caps were provided for our review, purchasers of this lens should also receive a semi-hard lens case, manual and registration card. This lens is also compatible with Sigma's 1.4x and 2x APO Tele Converters, although autofocusing is restricted with some cameras).
Handling
We conducted our Imatest tests of this lens on the EOS 5D, the standard body we use for testing all lenses of this type. We also fitted the lens to an EOS 40D body for some of our test shots. The mounting plate attached to both bodies positively and securely and the lens felt solid, nicely balanced and comfortable with each camera, although it probably wouldn't be quite as compatible with smaller camera bodies.
The working distance (from the front of the lens to the subject) at 1:1 reproduction ratio is approximately 20 cm. Attaching the lens hood reduces this to about 11 cm, which is quite good enough for photographing bees, bugs and spiders - as long as they're not moving too quickly. However, it tends to block light from built-in flash units.
As expected for an ultrasonic system, autofocusing with the review lens was fast (for a macro lens) and almost silent. However, the combination of high magnification and a very shallow depth-of-field made this lens quite susceptible to hunting, particularly with low-contrast subjects at high reproduction ratios.
The focus limiter was certainly helpful in restricting the range of this hunting but it can still take a while to get subjects sharp at 1:1 magnification. It's particularly difficult when the camera is hand-held, particularly with the EOS 40D body. This lens is much easier to work with when it's tripod-mounted.
We missed the indicators showing the different reproduction ratios. If you need this kind of information, you have to make your own calculations. The size of the lens - particularly with its hood attached - made it a bit too intimidating for portraiture. In addition the focal length was a little too long to give a pleasing perspective for head-and-shoulders shots.
Performance
Test shots taken with the review lens were quite impressive, with accurate colour reproduction and excellent edge-to-edge sharpness. Imatest confirmed the expected flatness of field of this lens and showed it to be capable of meeting expectations for the sensor in the Canon EOS 5D used for our tests.
Although we found a touch of edge softening at the f/3.5 aperture, by f/5.6 resolution had begun rising, reaching a peak at f/9 and declining slowly thereafter. Diffraction begins to cut in at around f/13 but fall-off in resolution is gradual. The graph below shows the results of our tests.
Lateral chromatic aberration wasn't quite as low as we found in the 50mm and 105mm macro lenses we tested. However, it remained within the ‘low' band at all lens apertures. In the graph below showing the results of our tests, the red line marks the boundary between ‘negligible' and ‘low' CA.
As expected from a fixed-focal-length macro lens, distortion was effectively negligible. Some vignetting could be seen at the f/3.5 aperture with focus set at infinity but it was largely resolved by f/5, another expected characteristic. Less corner darkening was found when the lens was set to focus at 46 cm.
Lens flare was particularly well controlled, although it was possible to produce veiling by pointing the lens directly towards a bright light source. Normal backlighting produced some attractive results. Bokeh was smooth and very attractive, particularly at wide aperture settings.
Conclusion
Sigma's 180mm f/3.5 APO EX DG HSM Macro is the only macro lens with a 180mm focal length for Nikon, Sony, Pentax and Four Thirds System cameras. Canon has an EF 180mm f/3.5L Macro USM lens with similar specifications to the Sigma lens. However, its RRP when this review was written was $2699, more than twice the price of the Sigma lens.
The closest Nikon equivalent is the AF micro Nikkor 200mm f/4D IF-ED lens, which was priced at $2799, when this review was written. Pentax and Sony camera owners are limited to the 100mm focal length for their macro lenses - and the Sony SAL100M28 100mm f/2.8 macro lens is currently priced at $1399.
All this goes to show the Sigma lens represents excellent value for money - as well as above-average performance in most respects. Photographers looking for a long macro lens should give this one serious consideration.
Buy this lens if:
- You want an affordable macro lens with a good working distance for photographing active insects and other small animals.
- You want fast and quiet autofocusing.
- You want a lens that remains the same length throughout its focusing range.
- You want a lens that requires no readjustment when you fit filters.
Don't buy this lens if:
- You require built-in image stabilisation.
- You're not prepared to use a tripod for critical macro work.
IMATEST GRAPHS
Based on JPEG files taken with the Canon EOS 5D:
SAMPLE IMAGES
Taken with the Canon EOS 5D unless otherwise specified:
Vignetting at f/3.5.
Vignetting at f/5.
Camera tripod-mounted; ISO 200, 1/10 second at f/2.8.
Camera tripod-mounted; ISO 800, 1/790 second at f/7. 1:1 reproduction ratio.
Taken with EOS 40D tripod-mounted; ISO 800, 1/790 second at f/4. 1:1 reproduction ratio.
Camera hand-held; ISO 800, 1/166 second at f/6.4. 1:1 reproduction ratio.
Camera hand-held; ISO 800, 1/166 second at f/6.4. 1:1 reproduction ratio.
Camera hand-held; ISO 400, 1/250 second at f/3.5. 1:1 reproduction ratio.
Camera hand-held; ISO 400, 1/49 second at f/8. 1:1 reproduction ratio.
Veiling flare with strong backlighting; ISO 200, 1/400 second at f/9.9.
Camera hand-held with moderate backlighting; ISO 800, 1/395 second at f/9.1.
Camera hand-held; ISO 400, 1/197 second at f/6.4.
Camera hand-held; ISO 400, 1/99 second at f/5. (Subject is approximately 2mm long.)
Camera hand-held; ISO 400, 1/790 second at f/5.6.
Camera hand-held; ISO 200, 1/125 second at f/3.5.
Camera hand-held; ISO 400, 1/197 second at f/5.6.
Camera hand-held; ISO 400, 1/125 second at f/8.
Camera hand-held; ISO 200, 1/1024 second at f/7.