The Sony 13-35 F4 is a fruit of cooperation between Sony and Zeiss, is one of the earliest lenses to come out for the Sony Full Frame system and thus is also very close to the original idea of compactness of mirrorless cameras (the idea that we can now consider officially abandoned in my opinion). It is less than 10cm long, weighs about 500g and in size resembles more its APS-C equivalents rather that the DSLR cousins, as you can see form the comparison below.
As you can see from the graphic above, you don’t really gain that much even if you go for an APS-C camera. I really wonder if Sony lenses are small of Fuji’s just so big (this is completely reversed in telephoto area). When zooming, the field of view actually becomes wider as the lens becomes longer so this gives you the opportunity to shoot some candid wide angle photos while your subjects thing that you are zooming in to something in the distance. The lens is super sharp (for a zoom lens) throughout its range, giving the best results in the lower (16-25) part of the focal range. The same with aperture, photos are sharp edge to edge practically on any F setting.
Now, let’s get to the bad part. All of my sharpness claims refer only to manual focusing. The lens has a tendency to make your photos completly milky in situations any other than perfect lighting, which of course in case of wide angle, landscape lenses is almost always. Whenever you have alot shadows, harsh light or sun in your frame, the lens will simply not focus (well, it will – if you shoot 10 photos with focusing each time you will get a few sharp). And even if the situation is perfect or if you are willing to shoot many photos and look for keepers afterwards, your photos will be acceptably sharp but they will never be as sharp as when you focus manually.
Manual focusing on a lens that wide is of course very easy and fast, it is also however very strange that it is not as sharp in AF mode, especially given a fact that at those focal lengths the depth of field in enormous. I really do not understand how shifting focus by even a few meters would result in losing DoF on e.g.18mm, but that’s what it does.
I don’t know if the problems were solved with some kind of firmware update because I sold the lens and bought a Voigtländer, I however did not hear about any such update. To be honest I will be buying this lens again, mainly because 15mm on the Voigtländer is a bit too much and it is a manual lens anyway, so I don’t have much advantage over SEL1635Z. As far as IQ goes of course the Voigtländer is better, but not very much so.