[Zig]

I'll give you a bit more of a detailed explore now, showing you 100% crops(unsharpened) of detail at apertures of f2.8, f11 and f22.
I'll give you the same at the focal lengths of 16mm, 25mm and 35mm.

Firstly, the 16mm end going from widest to smallest aperture, bottom left corner:







Odd this: there doesn't seem a great deal in it, does there? At f2.8 it seems wonderful...but you'll have to take my word that the upper left corner is very soft indeed, which doesn't go until f5.6.
See how at f11, even in the corner at the widest focal length of this lens, there's that reach into the shadows?
You'll also see that at f22 it's gone a bit soft: the "dip" in edge quality from f16(which is good quality) to f22 is more increased than the change from f2.8 to f5.6 at bottom left.

Secondly, 16mm end, f2.8/f11/f22 as before, this time looking at centre definition







:

I mean, nice, yes? Unsharpened an' all, at 100%: but again see how f11(middle) coupes the moutarde?

Now, we'll look at the other end, the 35mm: same rules apply: we'll look at f2.8, f11 and f22.
This time we see what's happening in the top right of the frame:







As you see, the vignetting is more apparent in the top corners at f2.8..this doesn't happily shift until f4. The top corners of this lens are ineed more troublesome throughout than the bottom L+R. Thing is, are you generally going to worry about corners at f2.8 if in a situation that requires you use the extreme lengths? I'm assuming, then, that grabbable street/low-light shots will have their own parameters of success. This lens is starting to make some sense to me as both a "landscape prime" and a candid/portaiture/journo lens. Mind you, I can tell you that 35mm at f2.8 on this lens is its worst performing area in terms of corners...and see the increased vignetting over the wide end?
You may have heard reports that the 35mm end of this lens does not perform as well as the other end: I'll now show you the centre, then, of the 35mm at the same apertures of 2.8, f11 and f22, as follows:







...and this time, in the centre, you'll see that performance is maintained to a greater degree right to wide open at f2.8. You'll have to decide for yourself if you think that the 35mm end at f11 is within reach of a prime: now, I'm sure it's not within reach of the 35mm f1.4 if reviews are anything to go by...but I think it ain't bad: and there is much consistency across the apertures here.

In Part 3, we'll have a look at a bit more detail...