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Sigma AF 70mm f/2.8 EX DG macro (Canon) - Review / Test Report |
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Lens Reviews -
Canon EOS (APS-C)
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Page 1 of 3
Review by Klaus Schroiff, published December 2007
Lens kindly provided for testing purposes by Sander Grootjes!
Introduction
The Sigma AF 70mm f/2.8 EX DG macro is the 5th and latest of the current macro lenses
made by Sigma. The local length of 70mm is a bit off the mainstream but it actually
makes sense. The Sigma is a full format lens but it is safe to state it will be mostly
used on APS-C DSLRs where its field-of-view is equivalent to ~105mm and this is actually
a quite classic perspective and it's also in the hot spot of portrait photography.
Another interesting aspect of the lens is the optical design. Unlike most other moderate
macro lenses it uses 3 SLD elements to correct optical flaws. This ambitious approach
has one obvious side effect - the lens is quite a bit more expensive than the 50mm f/2.8
macro and roughly on par here with the 105mm f/2.8 macro. Size- and weight-wise it is
also more comparable to its longer cousin.
The 70mm f/2.8 is part of Sigma's professional grade EX ("Excellence") lineup and
consequently the build quality is very good thanks to high quality materials
and quite tight tolerances. The focus ring operates pretty smooth. Unfortunately
it rotates in AF mode which is a slightly dated behavior on Canon DSLRs. As you can
see below the Sigma extends quite a bit towards close focus distances.
The metal lens hood is of the screw-in type which is a bit unusual but you can continue
to use a polarizer with attached hood. The front element does not rotate.
The Sigma has a conventional AF micro-motor which is very slow and quite noisy.
Unless you use the lens for macro photography it is a good idea to take advantage
of the focus limiter in order to avoid excessive AF hunting. The AF accuracy of
the tested sample was generally very good.
| Specifications |
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| Equiv. focal length | 112 mm (full format equivalent) |
| Equiv. aperture | f/4.5 (full format equivalent, in terms of depth-of-field) |
| Optical construction | 10 elements in 9 groups inc. 3 SLD elements |
| Number of aperture blades | 9 |
| min. focus distance | 0.257m (max. magnification ratio 1:1, ~6.5cm min. working distance) |
| Dimensions | 76x95mm |
| Weight | 525g |
| Filter size | 62mm (non-rotating) |
| Hood | Barrel shaped, screw-in type, supplied |
| Other features | focus limiter |
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