Sigma Sony Fit 17-50mm F2.8 EX DC HSM
Auto Focus Wide Lens
The Sigma 17–50 mm f/2.8 EX DC HSM belongs to the high-end series,
marked by the EX symbol. It starts with a metal mount inside which you
see the rear element with a diameter of 27 mm. It is placed at the level of the
mount for the 17 mm focal length and it collapses over two centimetres inside
when you pass to the focal length of 50 mm.
This lens covers a focal length from 17mm wide angle and offers a large aperture
of F2.8 throughout the entire zoom range, making it ideal for many types
of photography such as portraiture and landscapes.
It uses two elements made from Sigma's new 'FLD glass', plus two glass
mold and one hybrid aspherical elements, to reduce aberrations. The minimum
focus distance is 28cm across the entire zoom range, giving a maximum
magnification of 0.2x, and the 77mm filter thread does not rotate on focusing.
The Sigma 17–50 mm f/2.8 has some issues with the work against bright
light but fortunately they are not huge. You can catch light artifacts the
easiest at the shortest focal length and their intensity increases after the
stopping down of the lens. At 30 mm the flares are small and at the maximum
focal length they become negligible.
High image quality is assured throughout the entire zoom range. Incorporating
HSM (Hyper Sonic Motor), the lens provides fast and quiet AF. The lens
has a minimum focusing distance of 28cm (11”) throughout the entire zoom range
and a maximum magnification ratio of 1:5. The rounded 7 blade diaphragm
creates an attractive blur to the out of focus images. The inner focusing system
eliminates front lens rotation, making the lens particularly suitable for use
with the supplied petal-type lens hood and circular polarizing filters.
The 17-50mm f/2.8 EX DC HSM features the slightly simplified version
of Sigma's HSM (hypersonic AF motor). It is still fast and nearly silent but
full-time manual (FTM) override is not possible in one-shot AF mode. The AF
speed via in contrast AF (Live-View) is on the slow side. Manual focusing is
delicate due to the very short focus path - it just takes a turn of 30 degrees
to focus from infinity to the close focus limit. This approach improves the AF
speed for sure but you need to have some experts skills if you want to do it all
manual. The focus accuracy of the tested sample was fine on our test DSLR.
Please note that OS function is not available for Sony and Pentax mounts.
Specifications - Sigma Sony Fit 17-50mm F2.8 EX DC HSM Auto
Focus Wide Lens
13 groups 17 elements
• 2 FLD glass elements
Angle of view
Closest focus distance
28cm / 11in
Maximum reproduction ratio
Filter attachment size
83.5mm x 91.8.8mm (3.3in × 3.6in)
Kit Content Sigma (Sony Fit) HSM 17-50mm F2.8 EX DC OS Auto Focus Wide
Petal-type Hood (LH825-03)
For more information about, Sigma Sony Fit 17-50mm F2.8 EX DC HSM Auto Focus Wide Lens website.