This is the perfect lens for the Zf (after years of searching).
After over a year of trying every possible option on the Zf, my journey ends with the Sigma 45mm f2.8 i + Megadap Pro adapter. It's the only lens that completes the Zf's user experience value proposition due to it's size, weight, perfect aperture ring, IQ, and AF. Not to mention it's dirt cheap (got mine for $268).
My criteria were:
- AF
- Focal length 24mm-55mm
- Satisfying aperture ring
- Balance on the Zf without an added grip
Lenses I tried that didn't quite make the cut in order of how close they were:
- TTartisan 40mm f2: The only advantage this has over the Sigma is the max aperture which is useful for indoor situation like house parties, but it's IQ is much worse (including the fact that it doesn't actually cover the full sensor and you get really nasty corner vignettes that are not fixable). It also doesn't match the Zf's build quality like the Sigma does.
- Viltrox 26mm f2.8: This lens would be the best to buy along with the Sigma for something like a travel kit. However, the IQ isn't as good, the aesthetic and build aren't as good, and the aperture ring is tiny, rotates the wrong way, and doesn't feel nearly as good. And if you want to weather seal it, you need to add the hood and a filter which makes it bigger and dumb-looking IMO. Also the AF is quite bad.
- Sigma 35mm f2 i: Fantastic lens that is just a bit too big and front-heavy. That's it. For the same reason, I've excluded the Viltrox 35 and 55 EVO lenses. I own the 85 EVO and it's the exact same size and weight as those two and it's just too uncomfortable on the Zf. These lenses also have nice aperture rings but once I tried the i-series lenses every other aperture ring just feels sub-par**.**
Note about MF lenses:
My criteria requires AF, but that didn't stop me from trying to convince myself that the Voigtlander 40mm f1.2 Nokton was my perfect lens. Even aside from being MF, it was also too heavy and unbalanced on the body. I haven't personally used the 35mm f1.4 Nokton classic or the 40mm Septon, but I believe those two would balance perfectly on the Zf and I would 100% go that direction over the 40mm.
Note about non-aperture ring lenses:
The best of this bunch includes the Nikon 28 or 40 SE lenses of course. The 24-50 is also fantastic on the Zf and I would highly recommend it. All the Viltrox AIR lenses balance perfectly as well. Lenses that I tried to make work included the Nikon 24-70 f4S and the Tamron 16-30mm f2.8 which were both too big and heavy.
I hope this helps someone else with their journey. Happy to answer any questions you have!