Build quality is still amazing, it feels solid in the hands. For a 20mm lens, it is actually quite heavy to the 16-35mm, but they did not cheap on the quality of it. The design is so beautiful, but it comes it with some struggles i would definitely say. One is that based on the physics of the lens when you make something wides the glass will start to bend, we can tell that it gets to the point of fish-eye looking, and while to me this isn’t a problem because I do not use filters, for landscape shooters this might be a huge problem, and have yet to research it because i’ve used twice. Now, another one chink in the armor is that it only goes to f/16 compared to the native canon 24mm brother, which goes to f22, not a problem for me, but it might be for landscape shooters.
Don’t let the outside fool you though; I never thought that I would say that 20mm is a great portrait lens. I do have a 16-35mm, but as I have discussed in the past, that’s too wide. While indoors shooting with the 20mm and shooting for the first time, it felt like nothing special, but there was little distortion with a 20mm, everything else was MEH at best . Now, I went on to another photoshoot and decided to give this lens another try, and WOW; it was insane, I thought I was shooting with a 35mm for a second because there was no distortion, especially on the face it looked natural and looking around the edges, like the distortion was so minimal. This lens really made me want to shoot 20mm the whole time because I didn’t have to stand so far from my subject. I have a 16-35, but would never shoot portraits with it because of that distortion (even at 35mm my preferred focal length). I was given my words to eat,Sigma just crushed it and made me have a different look on it. One thing that is weird though, is that when I was editing and using “auto” to correct the straightness it would misread and make the faces look wider, it made a problem i guess.
Focusing - I know that in the past the sigma lenses, especially the 35mm when it first came out had a huge back focusing issue, but when I used this lens the focus was really good. I wouldn’t say it compares to a 70-200, but in terms on speed I would put it up there with the 24-70. It had to problems with focusing on the center points, which is good because that’s a majority of the points that I use, but it did start to struggle a bit when it came the outer focus points, which is common and surprisingly did not bug me because it was expected; I was surprised it picked up so fast.
Colors - The colors man, are natural and i think it’s just the combo of the canon handles colors and the way that the sigma renders. I’m fully blown away with the combo. I can’t seem to ever get those colors with the 35mm or any native canon lenses it’s odd and bugs me a bit, and I think it’s something that canon would pick up.
Contrast - I don’t know how Sigma does it, but the contrast on the lens is insane. When it comes to Canon lenses I find myself really pushing that contrast, but with the Sigma lenses the contrast is already there, it BAM !!!! Don’t worry about it, and phrase “i’ll fix in post” disperse in a good way. This lens just gets the colors right and contrast right, making it less work to fix in post.
1.4 - When it comes to 1.4. the Bokeh is really creamy and soft. One thing that I did notice with the lens and former sigma lenses is that they always handle brightness way different for some off reason I don’t have to push my ISO so high, nor lower my shutter speed so much, this might be because the t-stop on the sigma is as true as it’s 1.4. T-stops are the T-stops measuring the light that fall on your censor. f-stop front open and the length of the barrel. so it means that more light is coming in, thus it might be the reason that sigma lenses always look so bright (sigma - t1.5). But check out Tony and Chelsea for the info, they have great explanation on it and that’s where this thesis information and conclusion derives from.
Lens vignetting - I mean, I always between 1.4 and 2.8 when it came to the first two timesI used it, but it was a pretty heavy vignetting. I have always been a fan of the lens vignetting, so it was no problem and nothing a little post can’t fix.
Chromatic - None existent at this point, and if i did see any it was so minor that as a photographer you shouldn’t even care about it because untraceable unless you pixel peep, and something that your audience won’t even see depending on the way you edit.
Sharpness - It’s like a knife from hell’s kitchen and that’s all I have to say about sharpeness!
Amazing lens, all I have to say it WOW. I really am thinking about just going all sigma because of the colors and contrast. I would highly suggest picking this up.