Over the past few years, Canon has released no less than four EOS R mirrorless cameras with APS-C sensors: R7, R10, R50 And R100—in descending order of price and performance. However, underwater photographers have fewer options when it comes to Canon’s RF mount lenses designed specifically for crop sensors. There are only two: the Canon RF-S 18–45mm f/4.5–6.3 IS STM, with a 29–72mm equivalent focal length, perfect for fish portraits and pairs well with wide-angle and macro wet lenses; and Canon RF-S 10–18mm f/4.5–6.3 IS STMhas a 16–29mm equivalent zoom range making it a solid choice for capturing reef landscapes, shipwrecks, and large animals.
Finally, today, some alternatives were announced: Sigma is now offering 18–50mm f/2.8 DC DN And 10–18mm f/2.8 DC DN Lens with Canon RF mount. In both cases, L-mount, Sony E-mount and Fujifilm X-mount versions are available. Sigma also announced four prime lenses for the RF mount: 16mm f/1.4 DC DN, 23mm f/1.4 DC DN, 30mm f/1.4 DC DN and 56mm f/1.4 DC DN. All six are designed to work with APS-C cameras—or full-frame cameras in APS-C crop mode.
Both the 18–50mm f/2.8 and 10–18mm f/2.8 are constructed using 13 elements in 10 groups and have 7 aperture blades. The 18–50mm f/2.8 lens is 2.9 inches (74.5mm) long, weighs 10.2oz (290g) and has a minimum focusing distance of just 4.8 inches (12.1cm), while the The 10–18mm f/2.8 is slightly shorter, at 2.4 inches (62mm), weighs an ounce more, at 9.2oz (260g), and focuses only slightly closer, at 4.6 inches (11.6cm). With a significant speed advantage over equivalent Canon lenses, both of these new Sigma lenses could prove to be more impressive optically.
The Sigma 10–18mm f/2.8 DC DN and 18–50mm f/2.8 DC DN are priced at $600 and $550, respectively.
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