I decided to get this lens. I checked it out in the store to see how far back and how far front it went, and I found that everything was more or less where it should be, but it did move forward quite a bit. Distortion is difficult from 17mm to 35mm, and at 50mm we get a little pillow that is not particularly powerful. The vignette is striking when viewed at 17mm, but at 40mm it becomes practically undetectable. You can notice that the subject is limping horribly in bright images taken throughout the day even if you don't look too closely. That's not a problem at all. The thing that was the most bothersome about it was that it washed the edges on all focal lengths, and it was noticeable. If you add up all of the soapy edges, you get about a quarter of the photo that is decently exposed in general. I'm not sure what caused it, but the camera's shutter speed of 1/160 second, which would sometimes be on and sometimes off, produced images that were either clear or blurry, depending on the circumstance. stub. Regardless of whether or not it functions, the stub is still nonsensical. At a shutter speed of 1/100, he was able to completely do away with the smudge, while at 1/8, he was able to take a clear picture. By the way, when set to 2.8, the camera produced photos that were more or less clear. After handing it over to the business, I collected myself and regained my composure. Never in my life will you see me buy Sigma again. Notwithstanding the fact that there might be an occasion like this.