Another follow-up post on where I am with the Z system:
First up, the Z 24-70mm f/4 S: I tried it again on the Z 6 a couple of times, and it basically *is* a fine lens, it's the "right" size and everything - but: It doesn't have enough of a clear advantage compared to any other option if (and that's not such a big "if", considering the overall quality of the Z lenses) the Z 24-120mm f/4 S can compete with it optically. It's neither especially small nor light (it's smallish and chunky collapsed - extended, it's more or less the same size and weight as the Z 24-200mm f/4-6.3), nor are its - very good! - optics so extraordinary as to turn it into a must-have in the context of the Z system. Moreover, the key thing I found out is that I actually *don't mind bigger lenses on the FX Z bodies as long as they're well balanced* (like the Z MC 105mm f/2.8 S or the Z 24-70mm f/2.8 S). Long story short: If the Z 24-120mm f/4 S doesn't turn out to be a failure, I'll swap the Z 24-70mm f/4 S for its more versatile, only slighty bigger and heavier sibling as soon as possible.
And now, for the Z 40mm f/2: This is a much more complex lens than I expected - one might even call it a bit controversial. First off, it's small and light as advertised, and its optics are actually pretty good. So, it turns my Z 6 into a package small enough to fit neatly into my daily bag (instead of the Z 50 or Z fc), and you can rely on it to deliver on the whole. However, there are quite a few quirks I didn't expect after the pleasant surprise the Z 28mm f/2.8 SE has been - the rendering from the Z 40mm f/2 is a bit harsh and inconsistent overall, and neither easy to predict nor to control because it changes quite a bit, depending on aperture and subject distance.
So, at a second glance, this is not a worry-free lens (like the Z 28mm f/2.8 SE or the Z 35mm f/1.8 S - both not completely flawless, but absolutely dependable). At or near its closest focusing distance, spherical aberrations are obvious, sharpness is reduced, and you get distinctly "feathered" (fuzzy, one might even say "smeared") bokeh; howeever, at twice the minimal focusing distance and beyond, things smooth out quickly, at least if there's a wide transition zone in the image, not distinct layers.
I need to mention here that this isn't the first lens that exhibits a comparable behaviour - both the Fujifilm 23mm f/2 WR and one of my favourite lenses of all time, the Sigma 45mm f/2.8 Contemporary, showed similar tendencies; however, on the Z 40mm f/2, they're far more obvious (well, at least more so than on the Sigma - the Fujifilm can have its own funk going at very close distances). You can mitigate the problems by stopping down two stops at close-up, but this means losing the subject isolation capabilities the fastish aperture offers. In all fairness, this isn't something to make everyday photography impossible or even particularily difficult - not at all. But the Z 28mm f/2.8 SE is really quite a nice performer at close distances, as is the Z 35mm f/1.8 S, so it's kind of a let-down that the Z 40mm f/2 clearly isn't. You can't just move in and expect everything to be okay.
Another word about bokeh: It can look quite harsh - because the overall rendering is bold rather than smooth, contrasty and gritty. For everyday reportage, this might actually be considered a bonus (it is for street photography!), but the lens is less of a creative tool than its f/2 aperture would suggest, at least on the Z 6 (or FX); the 60mm-e FoV on the Z 50 made for a more satisfying experience overall, as today's result with that combo clearly showed.
It's still early days for me with this lens, and the Z 40mm f/2 certainly gets a lot right: basic attributes like size, FoV and aperture, quiet and quick AF, good handling (well, it's hard to get a minimalist tool wrong, but still) and a build that's much less plasticky than looks (and facts!) might suggest. But I'm less taken than I had hoped with the lens as a "brush", so to speak.
To wrap this up, at least for now, I want to put my observations into perspective: While in the context of the Z lineup. this lens might not excel, it's *still* a technically better lens than any comparable lens in the Nikon line-up I know of; it clearly beats the Nikon 50mm f/1.8D and older, and in terms of optical problems, while it has clear and distinct ones, in reality, they're *much less obvious and intrusive* than those I put up with with "good" lenses of the past, like the 35mm f/1.8G DX or 50mm f/1.8G (the latter remains one of my favourite "cheap" lenses; I moved it on when the Z 50mm f/1.8 S came along because I wanted to keep the 60mm f/2.8G Micro, but 50mm f/1.8G was a nice tool nevertheless). So, please, take my somewhat critical view of the Z 40mm f/2 with more than a single grain of salt. My "disappointment" is rather mild - and mainly triggered by the fact that I really, really like the Z 28mm f/2.8 SE, especially on the Z fc (at 42mm-e!); I thought the Z 40mm f/2 would turn the Z 6 into a "carry all day" alternative, but it probably won't; I guess I'll continue to favour the Z fc with the Z 28mm f/2.8 SE - which isn't a bad thing at all, because I intend to keep that camera anyway, and love the combo.
The Z 40mm f/2 will become part of my Z travel kit centered around the Z 6, alongside the 24-200mm f/4-6.3; it'll play the "small carry-along" part that's simply indespensable when on the road. However, contrary to my hopes and - unreasonable! - expectations, I'm thinking about adding another, less temperamental lens as well. I'll have to see about that - because there's no obvious candidate among the lenses I currently own (curse the versatility of the 40mm FoV!
).
So, yes, the Z 40mm f/2 is a keeper, but it's not the do-all, end-all solution I wished it to be. Honestly, I would have been surprised, but also elated, had this been the case. I'll continue to explore the lens for the next couple of days - it's definitely worth getting to know it even better before deciding whether and what to pair it up with for travel.
M.