Here is a Canon RF-S 18-150mm f/3.5-6.3 IS STM review by one of our favorite…
Sigma 18-35mm f/1.8 DC HSM specs:
- Aperture Range: f/1.8-16
- Fast Constant Maximum Aperture
- Designed for APS-C-Sized Sensors
- 35mm Equivalent Focal Length: 27-52.5mm
- Hyper Sonic AF Motor
- Internal Focusing and Zoom Design
- Four Aspherical & 5 SLD Glass Elements
- Super Multi-Layer Coating
- Compatible with Sigma USB Dock
One of the winning points of of the Sigma is clearly the constant f/1.8 aperture, but the reviewer also praises the excellent optics and build quality, the fast and precise auto-focus, and – last but not least – the affordable price tag of $799. In the conclusion the reviewer writes:
The Sigma 18-35mm f/1.8 zoom lens is wonderful. The optics are about as good as it gets, the bokeh is creamy delicious, the build is great, and the big f/1.8 aperture puts this lens in a class of its own. Honestly, there’s really nothing to complain about. The only issue is coming to terms with the short zoom range and making sure you have another lens available in case you need something longer. Oh yeah – I can’t forget about the price. Remember how I said that DxOMark rated the Sigma 18-35mm f/1.8 zoom higher than the Canon EF 24-70mm f/2.8L II when both were mounted on a crop-sensor camera? Now consider the Sigma’s $799 MSRP. That’s about one-third the price of the Canon 24-70mm f/2.8L, less than half the price of the Canon EF 16-35mm f/2.8L II USM […] It’s also going to perform better on your crop-sensor DSLR than any of those bigger, more expensive lenses. So if you want it, buy it. You won’t regret it.
I recommend you have a look at the review since it comes with much more information and sample pics. Even more samples shot with the Sigma can be seen here. The Sigma 18-35mm is expected to start shipping on August 15.