No zoom is perfect, 24-105 has “only” F4 and harsh bokeh at times. But also bulky to what I was used to, but on the ok side. It’s also not the sharpest or most contrasty lens. But overall very good.
16-35 is a lot better in sharpness, contrast and micro contrast. Giving the image almost a 3D effect.
The 28-70 is a bit sharper / contrasty then the 24-105, certainly when both af f4 but also already wide-open. Except wide open close focus. In that area the 24-105 excels. This Sigma feels less sturdy then the other two lenses. I even like the s primes build quality better, and those are better weather sealed.
The first one I had I liked very much. But somehow, maybe because I paid a lot more for this new one, I’m a bit more demanding somehow. At least I can now look beyond this close focus issue. It’s as designed and didn’t notice it on the first one so it got me a bit by surprise. I was sitting at my desk and it was one of the first snaps I took with it.