TL;DR: I stopped chasing “widest + fastest” and got cleaner stacks by prioritizing low coma + predictable infinity focus, then shooting a touch stopped down.

Hey, been there… on my Z body I found ultra-wide zooms were awesome for composition, but the corners got messy (coma + stretching) unless I nudged to ~f/2.8–f/3.2. With a mid-wide prime, even at f/2-ish, stars stayed tighter and stacking was way easier cuz vignetting/gradients were more consistent frame-to-frame. Also, I basically ignore the 500-rule now—use NPF-ish times, nail focus with 10x zoom on a bright star, then tape the ring. idk but that was the BIG upgrade for me. gl!

TL;DR: I stopped chasing “widest + fastest” and got cleaner stacks by prioritizing low coma + predictable infinity focus, then shooting a touch stopped down.

Hey, been there… on my Z body I found ultra-wide zooms were awesome for composition, but the corners got messy (coma + stretching) unless I nudged to ~f/2.8–f/3.2. With a mid-wide prime, even at f/2-ish, stars stayed tighter and stacking was way easier cuz vignetting/gradients were more consistent frame-to-frame. Also, I basically ignore the 500-rule now—use NPF-ish times, nail focus with 10x zoom on a bright star, then tape the ring. idk but that was the BIG upgrade for me. gl!

Quick question — are you stacking like ten+ frames, or mostly single-shot? That kinda decides f/1.8 vs f/2.8 imo. For Z-mount, Nikon NIKKOR Z 20mm f/1.8 S is the “safe” astro pick (coma’s decent, corners clean-ish stopped to f/2.2). If you want wider + budget, Viltrox AF 16mm f/1.8 Z is shockingly good for the money, but vignetting wide open is a thing. For adapted, Sigma 14-24mm f/2.8 DG HSM Art for Nikon F-mount is solid if you can live with f/2.8 + size

- For your situation, I’d go Nikon NIKKOR Z 20mm f/1.8 S — I’ve used it for years on Z bodies and I’m honestly super satisfied: sharp corners stopped down a hair, low coma, and it actually nails infinity focus without drama.
- If you want wider, Nikon NIKKOR Z 14-24mm f/2.8 S is the clean “no complaints” choice, but for pure Milky Way light-gathering the 20/1.8 is hard to beat for your budget, you know? gl!

TL;DR: I stopped chasing “widest + fastest” and got cleaner stacks by prioritizing low coma + predictable infinity focus, then shooting a touch stopped down.

Hey, been there… on my Z body I found ultra-wide zooms were awesome for composition, but the corners got messy (coma + stretching) unless I nudged to ~f/2.8–f/3.2. With a mid-wide prime, even at f/2-ish, stars stayed tighter and stacking was way easier cuz vignetting/gradients were more consistent frame-to-frame. Also, I basically ignore the 500-rule now—use NPF-ish times, nail focus with 10x zoom on a bright star, then tape the ring. idk but that was the BIG upgrade for me. gl!

This ^

Ok so before you drop $$800–1500$$… two quick qs: are you mostly doing *single-frame* shots, or are you stacking like 10–30 frames and fixing foreground separately? And what’s your usual sky quality (Bortle-ish, or “suburb glow”)? That changes whether ultra-wide at f/2.8 is “enough” vs needing f/1.8.

You might find this useful: the “lens coma / star performance” lists on sites like Lenstip and Photons to Photos-style data (esp vignetting + transmission) are clutch, plus user samples on DPReview forums. Also grab a phone app like PhotoPills or PlanIt Pro for exposure limits and Milky Way timing—saves soooo much trial/error lol. cheers

Quick reply while I have a sec - if youre looking for reliability and want to stay under budget, I'd honestly look at fully manual glass. Focus-by-wire on native Z lenses can be a headache because you lose your *exact* infinity position every time the camera sleeps. Here are a few professional-grade resources and budget-friendly routes that haven't been mentioned: - **Lonely Speck** and **Ian Norman's** reviews are basically the industry standard for testing sagittal coma flare and transmission. They have a massive database for wide-angle performance.
- **AstroBin** is the best place to see real-world stacks. Filter by the Z6 II sensor to see how much vignetting people are actually dealing with in post-processing.
- The Laowa 15mm f/2 Zero-D for Nikon Z is a dark horse here. It's well under your $1500 limit, and since it's a mechanical manual focus, it has a hard stop at infinity. It’s way more reliable for consistency across a 30-frame stack than an AF lens that might shift. - If you don't mind the FTZ adapter, the Tamron SP 35mm f/1.4 Di USD is technically one of the most corrected lenses ever built for coma. Using a 35mm for mosaics gives you *way* more detail than a single 14mm shot. Tbh, whatever you buy, just make sure to test for de-centering immediately. High-end wide-angle glass is sensitive to shipping shocks, and you want those corners to be symmetrical for clean stacking.

TL;DR: Consider the Sigma 20mm f/1.4 DG DN Art adapted with a Megadap ETZ21 Pro—f/1.4 is a total game changer for noise. Honestly, I’m still a beginner but I’ve been diving deep into the specs lately. I started using the Sigma 20mm f/1.4 DG DN Art on my Z6 II with a Megadap adapter and the extra light gathering compared to f/2.8 is just wild. It makes stacking 10 frames look like 30 in terms of signal-to-noise ratio. Technically, the coma control is reallyyy solid too, so stars stay round even near the edges instead of looking like little seagulls. It’s definitely a heavy lens and the adapter adds a bit of bulk, but for the performance you get, it’s hard to beat if you want the cleanest raw files possible. Does the extra weight bother you for your tripod setup? Anyway, f/1.4 basically feels like a cheat code for astro, but that's just my two cents!

Works great for me

Wow ok that changes things. Gonna have to rethink my approach now.

Yep, this is the way

Ok adding this to my list of things to try. Thanks for the tip!