This full-frame standard prime designed specifically for mirrorless systems was the first in Sigma’s I series line of lenses, and is designed as a portable day-to-day optic that balances perfectly on a modern mirrorless body. It can be used for a wide range of photographic applications, including portrait, street, wedding and travel photography, as well as general day-to-day shooting.
Optically the lens delivers outstanding results, with edge-to-edge sharpness even wide open at F2.8, with very well-controlled flare and chromatic aberration. Weighing in at just over 200g, it is Sigma’s smallest and lightest lens, despite sporting a beautifully constructed all-metal body, including a metal lens hood, a metal focus ring and a metal aperture ring. Combining style and substance, the SIGMA 45mm F2.8 is perfect for photographers or film-makers needing a high-performance standard prime with excellent build quality and an easy-to-carry design.
As with the other optics in the I series range of premium compact primes, the 45mm F2.8 has an all-metal build comprising precision-cut aluminium parts. Its robust construction and ultra-portable design make it perfect for street, travel and wedding photography, and the ideal lens for general day-to-day shooting. The lens has a rubber seal around the mount to keep out dust and moisture.
An aperture ring allows photographers to change aperture on the lens, or in Auto mode, on the camera if preferred.
The tactile knurled metal finish used for the lens hood, focus ring and aperture ring make handling the lens and changing settings extremely intuitive.
Metal mount with seal
Protects against dust and moisture.
Including metal aperture and focus rings.
Despite being extremely compact, the 45mm F2.8 does not compromise on optical quality. Its advanced optical design includes 8 elements in 7 groups, of which 2 are aspherical elements.
These help keep the lens compact while greatly reducing the appearance of chromatic aberration around areas of high contrast. Results are razor-sharp across the whole frame even when working wide open.
With its F2.8 aperture it possible to achieve a shallow depth-of-field for background fall-off. The bokeh is smooth and attractive and doesn’t distract from the in-focus subject.
The fast aperture is also useful in low light conditions, where the lens can be used hand-held with a reduced risk of camera-shake.
With a weight of 215g the 45mm is remarkably light for any lens, let alone a full-frame prime with a fast F2.8 aperture, an all-metal build and stunning image quality. It is designed so that it can be carried around anywhere without weighing you down, making it ideal for day-to-day shooting, and it pairs perfectly with smaller mirrorless camera bodies. The lens is less than a third of the length of Sigma’s 40mm F1.4 DG HSM | Art, and is just 17% of the weight, although its maximum aperture is a full two stops narrower.
The lens is part of the I series range of primes, which sit in the Contemporary line-up. They are designed to offer mirrorless photographers outstanding optical quality and premium usability in a compact package.
With similar optical character and the same sleek external design, the lenses are ideally used as a set, ensuring consistent bokeh, colour rendition, optical precision and usability.
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.
8 elements in 7 groups
Angle of view
Number of diaphragm blades
7 (rounded diaphragm)
Minimum focusing distance
Maximum magnification ratio
Dimensions (diameter x length)
ø64.0mm × 46.2mm
Corresponding AF mounts
L-Mount | Sony E
Sony E 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.
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 an image circle large enough to be used on a full-frame camera. It can also be used on cameras with a smaller ‘crop’ sensor, provided the mount is compatible.
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.
This switch toggles between autofocus and manual focus.
The diaphragm is constructed of nine rounded blades for a circular aperture opening and round out-of-focus highlights.