Prior to the introduction of the Sigma 18-35mm F1.8 DC HSM ($799 direct) lens shutterbugs with APS-C D-SLR cameras had to make a choice when it came to lens functionality. You can go with a zoom lens and cover a range of focal lengths, but even top-end models only opened up to f/2.8.

Sharp; Wide aperture; Reasonable price tag; Available for several camera systems

Big; No optical stabilization; Some wide-angle barrel distortion.

The Sigma 18-35mm F1.8 DC HSM was announced to widespread excitement, if only for the company's sheer ambition in making such a fast zoom. But this inevitably came with a degree of scepticism - it's hard enough to make an F2.8 zoom that's really sharp wide open, so could an F1.8 zoom possibly work?

Super fast constant F1.8 maximum aperture; Excellent optics; even wide open; Fast; silent autofocus; Solid build quality without being over-heavy; Compatible with Sigma's USB dock and Optimization Pro software

Restricted zoom range; Needs detailed AF microadjustment for best results; Inconsistent autofocus in difficult conditions even after microadjustment; Physically rather large for a standard zoom

Ground-breaking f/1.8 maximum aperture wide-angle zoom for APS-C DSLRs gets a workout

f/1.8 maximum aperture; Excellent image quality; Full-time MF option; Very good sharpness

Not full-frame coverage; Somewhat weighty; Modest 2x zoom range

On paper the Sigma 18-35mm F1.8 DC HSM effectively replaces fast 28mm, 35mm and 50mm equivalent optics in your camera bag, saving space and money whilst offering the convenience of a zoom lens.

The Sigma lens was bought primarily for the fast aperture on a 1.6 crop Canon 80D for my daughter's indoor portrait work. This lens has a chequered history with many articles about the problems with achieving accurate auto focus.

Sharp Focus

Got this lens for my canon 80d. I noticed very soon that I was having focusing problems. I was hesitant to attempt to use the dock, so I sent the lens of to sigma together with my camera and they calibrated it for me. It now works really well and I'm very pleased.

This is my second favourite lens to use overall and my favourite lens to use for landscapes. I own a Canon 80D and I love how sharp my photos look. I'm not too technical when it comes to lens specs but as a casual photographer I usually have this and my 24-70 in my bag.

The Sigma 18-35mm f/1.8 is a true game changer. I may not be a technical guru, but I love to snap pictures. I use my camera every day, and am always looking for new, incredible equipment that enhances my ability to capture a moment.

When sigma announced that it was developing the world's first zoom lens to feature a super-fast, fixed aperture of f/1.8 throughout the focal length range, the news certainly turned some heads in the photography world.

When the announcement of Sigma's new 18–35mm lens arrived, some of our staffers chuckled upon opening the e-mail. Why? Because of what appeared to be a typo in the headline: Instead of f/2.8, it quoted f/1.8 as the maximum aperture!