Introduction The Sigma 18-50mm F2. 8 DC DN | C is the latest addition to Sigma's 'Contemporary' range of affordable lenses. The 'DN' in the name stands for 'Digital Native' and denotes that it's designed for mirrorless cameras while the 'DC' indicates that it covers and APS-C sensor.
The 18-50mm focal length range is equivalent to 27-75mm in full-frame terms, making it a useful, fast standard zoom.
It will be available for the Leica/Panasonic/Sigma L mount but it's the E-mount version we're most interested in, since there are so many APS-C Sony cameras that would benefit from a small, fast lens.
Size
And the Sigma 18-50mm F2. 8 is impressively small. It's around 75mm long at its shortest (zoomed out to the 18mm setting) and just over 65mm wide, meaning it doesn't create an overly large or unbalanced combination when mounted on the likes of the Sony a6600, as seen here.
Design
The 18-50mm uses 13 elements in 10 groups, with one 'SLD' super-low dispersion element and three aspherical elements. Sigma says it has minimized the number of elements and that this, combined with digital correction of geometric distortion and lateral chromatic aberrations, results in a lightweight lens that delivers 'superb optical quality. '
E-mount owners will need to ensure that 'Shading Comp. ' and 'Distortion Comp. ' are turned on in 'Lens Comp. ' sections of their cameras' menus, to ensure the camera applies the corrections that make up part of the lens' design.
Weight and handling
The lens's body is made from a polycarbonate that Sigma calls 'Thermally Stable Composite' that expands in a similar manner to aluminum in response to heat, to ensure the lens performs consistently across a wide temperature range. Sigma says that key internal components are made from metal, to maximize durability.
The result is a lens that weighs 290g (10. 2 oz), but doesn't feel overly light or insubstantial, in use.
Other physical details
The 18-50mm uses an internal focus design, driven by a stepper motor, which we've found to be quiet and pretty fast (though not stunningly so) in our shooting so far.
There's a rubber gasket around the lens mount to form a seal with the camera body but there's no mention of additional sealing so, like most kit zooms, it's probably worth being a little cautious when the weather turns.
The lens comes with a reversible hood, designed to reduce stray light hitting the front element. Sigma's 'Super Multi-Layer Coating' has also been applied to keep any flare under control.
The small, light design sees a relatively simple 7-blade aperture used in the lens, but the blades are rounded to keep the bokeh patterns circular as you stop the lens down. A fairly small front element means the 18-50 can accept small and affordable 55mm filters, but also increases the likelihood of bokeh taking on a cats-eye shape as you approach the edge of the frame.
Mounts
The Sigma 18-50mm F2. 8 DC DN C, pictured alongside the Sony E 16-55 F2. 8 G. The Sony lens offers a greater coverage but is appreciably larger and significantly more expensive.
In terms of L-mount, there aren't many APS-C cameras, and we doubt many Leica TL or CL users are clamoring for an affordable fast zoom. Several full-frame L-mount cameras offer 4K/60p from an APS-C region of their sensors, but we're not sure how many videographers are using Super35 mode enough to want a dedicated lens for it.
Sony users, however, have a lot to gain from the new Sigma, though. Sony makes a 16-55mm F2. 8 G, which covers an appreciably wider range than the Sigma, but it's also 12% wider, 25% longer, 70% heavier and 250% more expensive. An awful lot of people who've bought ~$500 a6000 series cameras now have a much more affordable way to replace their kit zoom, without having to spend $1400 on the Sony F2. 8 G.
For E-mount users
Perhaps our only slight disappointment is that the new Sigma doesn't offer image stabilization. Doing so would add to both size and cost, which would both risk reducing its appeal, but given that only two of the seven Sony a6000-series models (and none of the NEX cameras that preceded them) have in-body stabilization, it would have been a valuable addition.
That said, a great many of those cameras will have been sold with Sony's 16-50mm F3. 5-5. 6 retractable power zoom, which, to put it politely, prioritizes compactness and convenience over image quality. For anyone using that lens, the Sigma 18-50mm F2. 8 offers a huge increase in optical consistency, as well as the shallower depth-of-field and increased low light performance promised by the wider maximum aperture. And does so without adding unbearable amounts of size or weight.
Conclusion
The Sigma 18-50mm F2. 8 represents an attractive choice for anyone looking to replace their kit zoom which, given it's the lens many people use most often, is a step well worth taking. Along similar lines, Tamron offers a stabilized 17-70mm F2. 8, which also has a lot going for it. But, while the Tamron adds image stabilization, and extra reach at both ends of the range, it's 60% longer and 80% heavier, as well as being more expensive.
The Sigma represents an interesting and affordable addition to the E-mount lineup. Now we just have to hope that, like the DC DN prime lenses, we get to see a version for Canon's EF-M mount, too.
. dpreview.com2021-10-21 17:00
