Handling and features
ePHOTOzine's expert, Gary Wolstenholme,
gets to grips with the Sigma 70mm f/2.8 macro lens – and he is impressed.
Sigma have slotted this lens into the already crowded macro lens market, and with a focal length of 70mm, it sits comfortably between shorter 50mm or 60mm macro optics and the popular 90-105mm lenses where the slightly longer focal length will provides a more comfortable working distance. Priced at around £380, it is currently the same price as Sigma's 105mm macro offering.
Tamron currently offer a 60mm F/2 macro lens, which costs around £390 and has an internal focus mechanism and a brighter maximum aperture but is only suitable for APS-C sensor SLRs. Canon's 60mm F/2.8 is priced at around £360 and also has internal focusing, but is only compatible with Canon's EF-S cameras. Nikon currently offer three lenses around this focal length. Their venerable 60mm F/2.8D harks back to the days of film, but only costs around £320. Their other 60mm is a newer design with internal focusing priced at around £400. Finally, Nikon offer an 85mm F/3.5 macro optic priced at £420, which is only compatible with their DX sensor cameras.
Sigma 70mm f/2.8 EX DG Macro: Handling and features
Typical of Sigma's EX series of lenses, this 70mm is coated in a kind of powder coating, which looks very smart when new. A gold ring around the front of the barrel denoted that this is one of their professional quality optics. On the whole, the lens feels very solidly put together.
Although this lens does sport Sigma's Hyper Sonic focusing motor, it focuses fairly quickly at normal distances, and the focus limiter switch prevents the lens from tracking back and forth throughout the entire focus range if it can't obtain lock at the first attempt. At closer distances, the lens does tend to hunt a little during AF, but this is typical of this kind of optic. Unfortunately, there is no way to disengage the focus ring during AF, so care needs to be taken not to catch fingers on the focus ring as it moves back and forth. Focusing manually is easy enough, but the mechanism doesn't seem as well damped as I've experienced on other similar-priced lenses. The manual focus action feels a bit loose as a result.
The lens extends by almost double at its closest focus, so the front element feels quite close to your subject, which may cause some issues with getting even light in on your subject. However, it is noticeably more comfortable at close distances than say a 50mm macro lens would be.
Sigma 70mm f/2.8 EX DG Macro: Performance
For this review, the lens was tested on a 12Mp Nikon D700 using Imatest.
It seems that Sigma have put a lot of effort into the optical design of this optic. On the whole, the resolution performance can only be described as superb. Right from F/2.8, the centre resolution is already approaching excellent levels, and the sharpness towards he edges of the frame isn't far behind either. Of all the lenses I've tested, this lens gives the most uniform sharpness across the frame, which is highly commendable. Stopping down improves the resolution a little, and diffraction doesn't begin to redce performance noticeably until about F/16.
Resolution at 70mm
Chromatic Aberrations are kept to very low levels and will not be noticeable under normal picture taking conditions.
Chromatic Aberrations at 70mm
For a wide aperture lens such as this, light falloff towards the corners is kept to a minimum. At F/2.8, the far corners are only 1.1stops darker than the image centre, stopping down to F/5.6 provides even illumiination across the frame.
This lens is also very well behaved when it comes to distortion, with Imatest only being able to detect 0.39% pincushion, which will be barely noticeable, even in critical applications.
Flare and ghosting is kept well enough under control. Strong point sources of light within the frame will cause a slight loss of contrast and light flaring. The front element isn't as deeply recessed as on other similar macro lenses. As a result, strong point sources of light outside the frame will cause a nticeable loss of contrast, if they catch the front element right. The supplied hood does a great job of keeping this effect to a minimum though.
Sigma 70mm f/2.8 EX DG Macro: Verdict
When I first saw the price of this lens, I was a little surprised that it isn't cheaper than Sigma's 105mm offering. After testing, using and seeing the results this optic can produce, I now know why. Sigma haven't cut any corners when it comes to optical performance, and as a result I feel this lens is keenly priced for the performance it can deliver.
Sigma 70mm f/2.8 EX DG Macro: Pros
Excellent resolution, right from F/2.8
Very good control of colour aberrations
Good value for money
Sigma 70mm f/2.8 EX DG Macro: Cons
Manual focusing experience not as pleasant as similar optics
Focus ring rotates during AF
Sigma 70mm f/2.8 EX DG Macro: Lens specification
|VALUE FOR MONEY
||Full-frame and APS-C
||10 elements in 9 groups
|35mm equivalent focal length (on APS-C body):
||95mm x 76mm
|In the box:
||Lens hood, padded case
The Sigma 70mm f/2.8 EX DG Macro costs £373.99 and is available from Warehouse Express here:
Sigma 70mm f/2.8 EX DG Macro - Sigma Fit