Nightscape/astro lens for Z6

Ernie Misner wrote:

EricTheAstroJunkie wrote:

BasilG wrote:

EricTheAstroJunkie wrote:

Jwmachon123 wrote:

Would the sigma 20mm 1.4 art be a rival to the 1.8s or is that still the better option

Thanks

No, the Sigma 20mm has terrible coma and some LoCA, it's sharp centrally, but that falls off to the edges/corners on full frame. The Z20mm is substantially better in every aspect.

I've used most lenses you can imagine for astrophotography (hence the user name), IMO your best options for astro as a beginner are:

Nikon Lenses:

24mmS (you must get a good copy, be prepared to exchange your copy due to decentering issues), it is sharper with less coma and roughly equal LoCA than the:

20mmS, very good lens, sharp to the edges, suffers from distortion that is better left uncorrected in post processing (RAWTherapee), slight amounts of coma and LoCA

50mmS, excellent lens for astro, very sharp with minimal coma and LoCA, suffers from copy variation however and you might have to exchange yours if you find decentering

24-70mm f2.8S, hulking monster with a slower aperture, very sharp except for at the widest focal length, expensive.

Sony lenses (requires adapter)

24mm GM, extraordinarily sharp, slight amounts of LoCA, almost no coma, better than the Nikon 24mmS, but requires the adapter and is more expensive (but with a faster aperture)

20mm G, I'd say my copy is slightly better than the 20mmS copies I used, some people have complained about coma/decentering and triangular stars, mine doesn't have this issue.

Sigma Lenses:

Art 40mm, there isn't a lens better than this for astro (wider than 100mm) currently on the market, it is the sharpest, most well corrected hunk of glass you can put on your camera. It can be shot wide open with no issues, but it is massive, it is expensive, and can be cumbersome, needs the ftz adapter.

Art 28mm, trumps all of these lenses in the sharpness, coma, and LoCA department, but is big, heavy, expensive and requires the ftz adapter.

Art 14mm, sharp, but suffers from coma wide open, doesn't accept filters, big and heavy, expensive and needs the ftz adapter.

Do you have any thoughts on 20/1.8 Z vs. 14-24/2.8 Z for astro-landscapes?

I haven't used the 14-24mm f2.8S for astro yet, so I can't really comment on the quality of that lens. The 20mm is a really good lens and I generally prefer primes with the extra stop of light vs f2.8 zooms, fwiw. Zooms tend to be weaker on each end of the range, so more of a "jack of all trades, master of one scenario" when nightscapes really require a master tool to execute at a high level (IMO).

Hi Eric! The F mount 14-24 f2.8 seemed to be the go-to astro lens for quite a few years. That makes me think the Z version will probably be even better for astro, but not quite as good as a dedicated prime like you said.

Actually the 14-24mm f2.8G was a pretty mediocre performer for astro, inflated by Nikon's pretty dedicated fanbase who wouldn't ever venture into the third party offerings from Sigma, Rokinon and others. The 14-24mm is fairly sharp centrally, which fell off somewhat strongly to the full frame edges, but still not as sharp across the frame as the Sigma Art 14-24mm. The Nikon had pretty average to poor coma control and noticeable LoCA, compared to its competitors it fared quite a bit worse in those two areas. Honestly other than the 28mm Nikon really failed to make an above average f-mount lens for astro wider than 35mm, pretty much all of them have really bad coma, average to poor LoCA, and poor edge sharpness. Luckily the Z-mount offerings seem to be a lot better, the 20mmS and 24mmS are great, from the few reviews I've seen the 14-24mm f2.8S seems to be very good. I think Nikon finally woke up to the Night Photography community and realized that Sigma, Rokinon, and Canon were all beating the pants off them for these uses.