Most of my lenses that I've owned over the years have all been Canon brand native lenses.  However, there are two cases where I made an exception for some truly exceptional lenses that offer value comparable to native Canon options.  Those two are the 35mm f/1.4 Art and 18-35mm f/1.8 Art by Sigma.  

 

My feedback is simply "wow."  If you own an APS-C camera, regardless of brand, this should be a lens you own.  The clarity is unmatched and the image rendering rivals Canon's L lenses.  It was a better quality image than the 17-55mm f/2.8 IS, even though it lacked IS and a longer zoom range.

 

My only two complaints are that the zoom range felt a bit limited, and that it did struggle with focusing.  Numerous times I gave my camera to grab a family photo, single occurrences that happen rarely in life on a family vacation, only to get home and see that the lens back or front focused pretty substantially.  For that reason alone I decided to part ways with it.  Now an owner of the 35mm f/1.4 Art though, I can confidently say that the focusing problems are no longer an issue on my R mirrorless camera.

 

I really enjoyed the 18-35mm Art lens when I was shooting on the Canon 80D and really missed that lens after parting ways.  There's just something about the Art series lenses that appeal to me.  A lot of reviews are critical of the Art line for being focused a little too heavily on sharpness, leaving the end images a bit cold and sterile feeling.  But what I see is extremely crisp and clear images that deliver a clarity only matched by L lenses.  It easily outclasses my 85mm f/1.8 and 50mm f/1.8 primes by quite a bit.

 

In addition to the clarity of the 18-35mm Art, easily one of my sharpest lenses, it delivered a really dreamy bokeh even for the wider angles of view.  While I didn't end up keeping it very long, it has definitely made a mark as the creative tool used in some of my favorite shots!

 

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