Originally posted by John Hales ...I want either the K3ii or K1 for the astro photography benefits. Otherwise I am a landscape photographer...
The K-5 used to be my main camera until I upgraded to the K-1. The K-1 excels at astro and landscape. The K-3ii can certainly do astro and landscape, but it tends to be better for action and wildlife.
The K-1, compared to the K-3, offers less noise, higher dynamic range, more resolution for wide targets, and the minor feature of on-body lights but I still prefer to use a headlamp to see. The K-3ii provides higher resolution for small targets because the 24mp are concentrated into a smaller area than on the K-1, faster burst speed, and a more compact body.
Lens choice for the K-1: f2.8 or faster doesn't get used for many landscapes but it is important for astro. Your options for astro and landscape usage include:
- Just 24-70: Get that as your all purpose lens if you don't expect to ever need wider than 24mm. 24/2.8 is an okay combination for the Milky Way.
- 28-105 plus 15-30. The 15-30 lets you go way wider than just the 24-70, and provides the f2.8 for astro.
- 28-105 plus a prime like Samyang/Rokinon 24/1.4 or 20/1.8. The Samyang primes are even faster than f2.8. Compared to the 15-30, the Milky Way will be brighter, but you lose the flexibility of zoom and autofocus. These primes and others offer more affordable filters than the 15-30.
(By "astro" I assume you mean relatively wide shots of the Milky Way, constellations, etc. using typical camera lenses. DSLRs do well with that. If you want to photograph small targets such as planets, star clusters, or galaxies through a large telescope, consider a dedicated astro camera rather than DSLR or mirrorless.)
---------- Post added 06-25-18 at 05:08 PM ----------
Originally posted by John Hales So then the debate is which lens the 24-70 or the 28-105
Your 16-85 plus K-5 acts like a 24-130 in K-1 terms. If 16mm on your K-5 is adequately wide, and you don't need the 85 end much, then the 24-70 sounds great for you. If you want wider, or need the full 16-85 today, you will likely need 2 or more lenses. That's how LBA (lens buying addiction) progresses