Sigma EX telephoto zoom lens - 70 mm - 200 mm F/2.8

...and has the now familiar Sigma 'smooth' black crinkle finish which tends to attract dust like a magnet (in my experience) but at the same time, is easy to wipe over and keep clean. A well designed and very welcome rotating tripod bush collar is included in the package, as is a lens hood (petal type) and soft case. A nicely finished and well presented product. Even the thin gold ring around the front of the lens barrel echoes the famous red one around ...
...APS-C) or 119-340mm f/2.8 on Sigma DSLR cameras. These make interesting options on the APS-C size sensor cameras and it can be assumed the camera has a completely different set of values when used with such cameras to those when used on full-frame. Interesting?

The fast f/2.8 maximum aperture provides great fun for shallow DOF (depth-of-field) shots where particularly at the 200mm end of the zoom, depth-of-field is excitingly shallow. ... more

I am pleased to say that I won this lens in a photo magazine photography competition and didn't have to pay for it. If I had, I might have been just a little disappointed. It's not a 'bad' lens by any means, just not a really 'great' one.

This is one of Sigma's EX (Excellence) range of lenses, which implies it is intended to fit into their 'professional' range of lenses and certainly, the quality of construction and finish clearly illustrate this. It is quite heavy and has the now familiar Sigma 'smooth' black crinkle finish which tends to attract dust like a magnet (in my experience) but at the same time, is easy to wipe over and keep clean. A well designed and very welcome rotating tripod bush collar is included in the package, as is a lens hood (petal type) and soft case. A nicely finished and well presented product. Even the thin gold ring around the front of the lens barrel echoes the famous red one around those of Canon's luxury 'L' Series lenses.

With internal focusing and zooming, the lens remains a consistent size whether focusing or zooming. This is nice as it retains the balance of the lens throughout all situations. Just as pleasingly, the front element does not rotate during focusing or zooming, making it very easy to utilise polarising filters.

The included rotating tripod collar further enhances handling in that when tripod mounted, weight is evenly distributed and the camera/lens combination never feels unbalanced. Furthermore, it is very easy to switch from horizontal to vertical format simply by loosening the tripod collar's clamp and rotating the lens, quite literally, on it's own axis. Excellent! This same collar is very easily and quickly removed whenever you choose to use the lens hand-held.

Being an EX DG lens, it is suitable for use on either FF (Full-Frame) or APS-C cropped sensor cameras when it effectively behaves like a 105-300mm f/2.8 (on Nikon APS-C), 112-320mm f/2.8 (on Canon APS-C) or 119-340mm f/2.8 on Sigma DSLR cameras. These make interesting options on the APS-C size sensor cameras and it can be assumed the camera has a completely different set of values when used with such cameras to those when used on full-frame. Interesting?

The fast f/2.8 maximum aperture provides great fun for shallow DOF (depth-of-field) shots where particularly at the 200mm end of the zoom, depth-of-field is excitingly shallow. Whilst the lens is referred to as 'macro' within it's descriptive title, the term is used somewhat loosely. True macro lenses provide genuine 1 to 1 life-size reproduction, this lens doesn't! Although both the previous and latest models of this lens focus to a highly respectable 100cm (1 metre), this does not provide 1 to 1 life-size reproduction, merely 1 to 3.5 at 200mm focal length. I do wish all manufacturers would be a little more 'honest' in their description of their product's specifications?

This lens has a large maximum aperture of f/2.8 which remains consistent throughout the zoom range and is fully compatible with the Sigma EX 1.4x or 2x APO Tele Converters, both of which maintain full AF (auto focus) facilities. The lens features Sigma's HSM (Hypersonic Motor) AF and is fast, accurate and very quiet.

Construction is a combination of metal and high quality plastics, along with a fair amount of large pieces of glass. Light it isn't but considering the specification and the fact that it has no less than 18 elements (in 15 groups), including 2 ELD (Extra Low Dispersion) ones, this is no surprise. A little surprisingly perhaps for such a fast (f/2.8) lens with a range of up to 200mm focal length, Sigma have managed to constrain filter thread size to a reasonably economical (over 82mm) 77mm.

The lens has a fairly moderate 3x zoom ratio and as such, the design shouldn't have presented too many problems. Accordingly, distortions are impressively low. There is still a small amount of barrel distortion at 70mm focal length, although nothing to worry about. This changes to moderate pincushion distortion at the longer end of the zoom range. Again, nothing to get too upset about.

Vignetting is not much of a problem when using the lens on cropped APS-C cameras, due to the sensor utilising only the central 'sweet' spot of the image circle. At 70mm, it is minimal, even at f/2.8. However, at 200mm, it does become noticeable at f/2.8 although stopping down completely eradicates the problem. This is not however the case when using the lens on FF (full-frame) cameras when vignetting 'is' visible, although not too much of a problem. However, at 200mm and at f/2.8 it 'is' really quite noticeable. Stopping down does improve the situation, so it is still not a major problem.

Resolution or 'sharpness' is for me, a little disappointing. At 70mm, even at f/2.8, it's not too bad, with the central area of the frame appearing quite sharp. The edges however, are just a little soft I find. I would describe it as VERY GOOD+ in the centre, VERY GOOD at the edges and GOOD in the corners. Stopping down to f/4 improves the edges and by f/5.6 the corners too have improved to VERY GOOD- in my opinion. This performance remains intact until just about 135mm but, at 200mm there's a turn for the worse. Central performance is still VERY GOOD- but edges have dropped to GOOD - unfortunately, the corners really lose it, falling back to a plain and simple SOFT. Not 'bad' overall but certainly disappointing compared to my superb Sigma 100-300mm f/4 lens.

I have seen reviews where this lens scores quite well for CA's (Chromatic Aberrations) or 'Colour Fringing' but my example certainly doesn't bear this out. Quite strong CA's are visible, even with relatively low contrast subjects at the longer end of the zoom range, from about 135 to 200mm. When faced with higher contrast or backlit subjects, CA's are really very noticeable and quite large - around 2 pixels at 135mm and up to 3 pixels at 200mm. To make matters worse, they are kind of 'soft' which makes them particularly difficult to eliminate in software. This and the slight 'softness' of this lens, spoil the whole thing for me I'm afraid.

This should be a really useful lens, both on FF (full-frame) and APS-C cameras and one which I would truly love to be able to recommend. Unfortunately, due to my own experience, I cannot.

My only advice would be - buy one by all means, perhaps 'you' will get a good one? If you don't and, you should carry out your own tests on it as soon as you get it, then take or send it back. I had to do just this with a Sigma 12-24mm lens. It took THREE examples before I got one which did perform well! I have for some time, believed that Sigma have quality control problems. They are not alone, it has to be said. There are some really big players out there with similar problems. All should get their act together. Its' simply not good enough to permit sub-standard products to reach the consumer.

David Chamberlain 

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