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Sigma AF 150mm f/2.8 EX DG HSM APO macro - 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 August 2005
Introduction
The Sigma AF 150mm f/2.8 EX DG HSM APO macro is one of the more interesting macro lens additions
to the market of the last few years. Upon first look the focal length looks a
little unusual but in a multi format era (35mm format, 1.3x, APS-C) things are
no longer how they used to be here anyway. Due to the intermediate focal length (between
the classic 100mm and 180/200mm macros) Sigma managed to provide a large max. aperture
(f/2.8) which is certainly a plus for portraits whereas on the other hand it offers
all capabilities of a true macro lens (1:1 magnification).
It is a designated DG ("Digital Grade") lens featuring a new coating
optimized to (shiny) reflection characteristics of today's image sensors.
However, the lens covers the full 35mm image format so it can also be used on a
film SLR. In the scope of this report the lens was tested using an APS-C DSLR
(1.6x crop factor) where the lens resembles a 240mm lens on a classic
full frame camera. As of today the lens is only available for Canon, Nikon
and in native Sigma mount.
Despite the large max. aperture the 150mm f/2.8 EX remains a very compact
with a size of just 80x137mm and the total weight is still moderate with 895g.
The filter size is 72mm. The package includes a barrel-type lens hood as well
as a soft case. The optical construction is made of 16 elements in 12 groups with
two SLD (Super Low Dispersion) elements and 9 aperture blades.
Typical for true macro lenses it features a floating system to maintain a high
performance throughout the focus range. The min. focus distance is 0.38m resulting
is a max. object magnification of 1:1. The lens is also compatible to the two
Sigma AF converters (1.4x, 2x) so it can be transformed to a 210mm f/4 or 300mm f/5.6
combination (336mm and 480mm on APS-C DSLRs) with max. magnifications
of 1.4:1 and 2:1 respectively.
The principal build quality of the lens is excellent using the typical EX ("Excellence")
finish (crinkle style), a very smooth focus ring and a solid tripod mount. The lens does not
extend during focusing nor does the front element rotate. The only very minor complaint
is the rather cheap feel of the AF-MF focus switch.
For a macro lens the speed of the near-silent HSM ("Hypersonic Motor") AF drive
is Ok but certainly not fast. Typical for macro lenses it takes some time to AF between the
extreme ends of the focus range. In order to prevent long range hunting in standard
situations Sigma has provided a focus limiter where you can choose between full-range,
0.52m-infinity and 0.38-0.52m. This set of ranges makes sense - the focus path from
0.38-0.52m is about as long as between 0.52m-infinity.
Thanks to the HSM AF drive manual focusing is always possible in (one-shot) AF mode.
It is quite interesting to note that the lenses looses between 1.5 to 2 f-stops in speed
when set to the min. focus distance. This is in line with other macro lenses featuring an
internal focusing (IF) mechanism. The focal length will also be affected here (aka reduced).
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