Small but perfectly formed, the 18-50mm F2.8 is the ultimate portable standard zoom for crop-sensor mirrorless cameras. With an equivalent focal length of 27-75mm on an APS-C camera the lens is well-suited to a wide range of photo and video applications, including landscape, portrait, street and architectural photography. It can also be used for macro-style photography owing to its impressive maximum magnification ratio of 1:2.8.
A constant F2.8 aperture makes it easy to achieve blurry backgrounds, which is ideal for shooting attractive portraits and close-ups. Autofocus is exceptionally fast and quiet thanks to the lens’ stepping motor, which can be particularly useful for shooting video or for capturing fast-moving subjects.
Weighing less than 300g, the 18-50mm is easily portable enough to be carried around for casual day-to-day shooting, but thanks to its outstanding optics, fast AF and wide aperture, it is more than capable of delivering professional-quality results.
The external barrel of the 18-50mm F2.8 is constructed using a polymer called Thermally Stable Composite (TSC). This has a similar thermal expansion rate to aluminium, meaning that the metal interior of the lens and the TSC exterior behave in the same way as temperatures change. TSC is also light and strong, and has a sleek finish.
The lens has an internal focus mechanism, so the lens always remains the same length when the subject distance changes. This makes it well suited to gimbal use due to a relatively constant centre of gravity, and it also means the end of the lens doesn’t rotate when focusing – important when using filters.
The lens has a stepping motor that delivers smooth, fast and accurate AF for both stills and video. It has been designed with lighter glass elements in the focus lens group, which ensures responsive autofocus that is fully compatible with all the latest AF camera technology.
The durable brass mount is surrounded by a rubber seal to help keep out dust and moisture.
Precision brass mount with seal
Protects against dust and moisture.
With smooth, accurate action.
Despite being extremely small and light at under 300g, the 18-50mm F2.8 DC DN | C delivers outstanding optical quality at all aperture settings. Optical performance is maintained across the whole frame, meaning fine detail is rendered perfectly right into the corners.
The lens has an advanced optical design made up of 13 elements in 10 groups, including 3 aspherical elements and 1 SLD element. These ensure razor-sharp results and work with in-camera digital corrections to eliminate chromatic aberration, flare, distortion and vignetting.
The lens has advanced optical coatings which reduce flare and ghosting when working in bright direct sunlight – especially important at the wider end of the zoom range.
The 18-50mm has a maximum magnification ratio of 1:2.8, giving it a minimum working distance (sensor to the front of the lens) of just 12.1cm. This makes it well-suited to close-up photography, including food, insects, flowers and other macro-type subjects.
Thanks to its wide F2.8 aperture across the whole zoom range the 18-50mm is a good performer in low light. This is ideal for photographers who want to shoot in darker conditions without a tripod.
One of the smallest standard zooms on the market for crop sensor mirrorless cameras, the 18-50mm is a truly pocketable option that allows photographers to work light without sacrificing quality. It is almost identical in weight to the 30mm F1.4 DC DN | C, a crop-sensor prime with a wider F1.4 aperture. Both are superb options for portable day-to-day lenses.
All Sigma cameras and lenses are designed, manufactured and assembled at our sole factory at Aizu in Japan. This domestic production model is unusual in today’s industry, with most imaging companies opting to outsource to other countries to reduce costs. But SIGMA believes that keeping virtually all manufacturing, processing and assembly in Aizu is essential for creating innovative, carefully thought-out and impeccably constructed products that meet the high standards demanded by professional photographers and film-makers around the world.
Sigma chose Aizu as its main production base in the early 1970s. Situated at the base of Mount Bandai in the Fukushima Prefecture, about four hours’ drive north of Tokyo, Aizu has an abundance of very clean water from mountain streams, which is essential for grinding and polishing lenses. Sigma’s founder, Michihiro Yamaki, was also drawn to this area for its workforce, who have a reputation for their craftsmanship, work ethic and attention to detail. Mr Yamaki’s son, Kazuto Yamaki, now the owner and CEO of SIGMA Corporation, has the same unwavering commitment to keeping production in Japan.
Today Sigma’s factory is more than 50,000 square feet in size, and packed full of some of the most advanced optical manufacturing technology in existence. So when you buy a Sigma camera or lens you can be sure that virtually every single component part has been manufactured and assembled by SIGMA, in Japan, with the greatest level of care and attention. We hope you enjoy using our products.
If you want to see how a particular SIGMA lens or camera performs, why not test drive it with our SIGMA Select hire service. Available for selected SIGMA lenses, short-term loans are free of charge (including shipping), with a small fee if you want to test it for longer. Refundable deposit required. Subject to availability.
13 elements in 10 groups
Angle of view
Number of diaphragm blades
7 (rounded diaphragm)
Minimum focusing distance
Maximum magnification ratio
Dimensions (diameter x length)
ø65.4mm × 74.5mm
Corresponding AF mounts
L-Mount | Sony E | FUJIFILM X
Sony E barcode
FUJIFILM X barcode
Specifications are for L-Mount
A special coating applied to the front element to help repel water and oil.
This suppresses flare and ghosting by minimising reflections within the lens, ensuring punchy, high-contrast results. All lenses in the current Sigma range feature this technology.
This describes the degree to which a lens can magnify an in-focus subject. The ratio shows the relationship between the size of the projection of a subject on the camera’s sensor (the left number) and its actual size in reality (the right number).
Internal focus or an inner focus system means the lens configuration uses movable internal lens elements that adjust focus without changing the length of the lens barrel. This helps keep the centre of gravity of the lens more constant when changing focus.
The lens has a filter thread around the front element onto which filters and filter holders can be attached.
The mount is the part of the lens that attaches to the camera body. A coated brass mount is used for strength, and is surrounded by a rubber seal to keep out dust and moisture.
The lens has an image circle large enough to be used on a camera with an APS-C / S35 (or smaller) sensor. It can also be used on cameras with a full-frame sensor, but only in the camera’s crop mode.
The diaphragm is constructed of nine rounded blades for a circular aperture opening and round out-of-focus highlights.