8 out of 10 points and recommendedFairly light, practical range of focal lengths, excellent IQ, Image stabilisation, Macro modeNone really
I can only imagine that SLR Gear was unlucky enough to get THREE faulty copies of this lens. Mine (used on a full frame 1-Ds ii) is almost as sharp in the corners as in the centre, even at full aperture, and does not show the terrible corner performance of the SLR gear tests. What is more even at the 50mm FL, which is supposed to be its worst, it performs at least as well as my 50mm f/1,8 prime lens, which is widely praised for its IQ.reviewed September 19th, 2015 (purchased for $600)
It is also fairly distortion free, especially at the wide angle end, at least it is very good when compared with the alternative 24-105mm lens from Canon.
The IS and focal length range makes it a great every day lens for most photographers, and more practical at half the weight of the f/2.8 version.
The Macro mode has been criticised elsewhere as leaving insufficient working distance, but that misses the point. This lens is not supposed to be your first choice for macro work. What it does is to provide excellent macro quality when you encounter an opportunity and do not have a 100mm or 180mm macro lens with you.
9 out of 10 points and recommendedWonderful image quality, lots of detail, contrasty, subject separation, fast and accurate AF, bright viewfinder, solid construction, unobtrusive in use, ...No weather sealing, makes all my other lenses look poor (even the 'L' zooms that, when I first got them, imagined could hardly be improved on).
SIx months on from buying it this has become my favourite lens ever, beating my previous favourite (Leica's 4th version of the 35mm Summicron for its M-series rangefinders).reviewed August 2nd, 2017 (purchased for $860)
I use it for everything, landscapes, townscapes, interesting detail, portraits.
It is harder work than using a zoom lens, and some shots I just cannot get at all (cannot get close enough, or far enough way) but the shots I do get are so much nicer looking than I get with any other lens that for me and my goals it is a fair trade off.
Some reviewers have listed lack of IS as a "Con". I disagree. IS is useful in my f/4 zooms but I don't need it to hand-hold this lens. The combination of a wide aperture and very little light lost in transmission makes very high shutter speeds possible. Besides, adding IS would mean adding extra elements and that would very likely reduce the image quality.
With weather sealing this would be a 10. As it is it is earns a 9. For comparison, no other lens I know of would earn more than 8/10
8 out of 10 points and recommendedWide aperture Fast focussing Solid build Excellent IQ overall Versatile Pleasant to useCorners are not so sharp as some alternatives Quite big and heavy compared to alternatives No Image Stabilisation Not weather sealed
This is not a lens I would have considered except that I was offered it at such a bargain price that I could not refuse. I have been nicely surprised. I find that having more flexibility in aperture makes a prime lens like this more useful than a mid-range zoom such as the 24-70 f/4 that it has replaced in my bag.reviewed September 6th, 2017
The corner sharpness that all the on-line reviews mention, and that some consider to be a terrible flaw is actually irrelevant to the way I use the lens. When I am shooting at a wide aperture it is usually because I want to set a sharp subject against a blur of colour. The background is out of focus anyway so the lack of corner sharpness is irrelevant. When I am shooting a landscape or townscape or interior, and want great depth of field I would be stopped down to f/5.6, f/8, or even narrower, and at those apertures the difference between centre and corner is not significant.
Another thing the lens has been criticised for is the filter size. For me it is no disadvantage. It can share 77mm filters with my Canon 16-35.
Finally a big deal is made of green and purple fringing in front of and behind the focus point. This is so easily corrected in LightRoom (one or two points in Lens Corrections, Colour, Defringe) that it is hardly worth a mention.