My plans were to stay with the crop body, and just continue shooting my K5IIs, waiting for the K3II replacement. I really like my K5IIs for most everything. However, I retired a couple of years ago, and was somewhat frustrated with getting better/more star color in my Milky Way over landscape shots. With a lot of contemplation, I thought that if I was driving anywhere from 1 to 3 hours one way out to get to a location to shoot, and with the new crop body no where in sight - and counting up what was in the piggy bank for a new body - I decided on upgrading to the K1 (this was before the mark II was announced). I needed more light collection with better dynamic range. I really only shoot at ISO 800 for my astro stuff (I don't need to go any higher). So, now I'm able to capture the star colors in the Milky Way - and satisfied.
The full frame lenses I had acquired over time all had varying amounts of coma (for astro use) or were not fast enough, so with some looking I found a 15-30/f2.8 to pick-up about 2 years ago. This last Christmas, I sprung for the 28-105 "kit" lens, which has some really excellent image quality. I want to mod my 60-250 for the rear light baffle - and that these three will be my main lens set. I do have some good primes, but I'm set.
I don't need higher ISO, or shallow DoF, but did need some better dynamic range at lower ISO (for better color), and just a larger sensor area for more light collection. I will say that the articulating rear screen is really nice to use for astro, and the built in GPS makes things much nicer.
I have one of the old K shift (perspective correction) 28mm lenses (that when fully shifted and stitched provide a 15mm shifted stitched image), that now captures full frame and is pretty nice to use, to get better architecture shots. I also have two converted older Contax Zeiss primes (28 and 85) that now have the full sensor projection, that provide some really excellent image quality.
Last edited by interested_observer; 02-15-2020 at 05:36 PM.