Originally posted by Emirena I'm just a hobbyist but would like the capability to shoot more pet, birding, and night shots - the areas where my k70's limitations were the most severe. I had evident noise well below 6400 iso, and difficulty with missed focus on moving subjects. Nothing else about the camera was any less than perfect in my opinion.
Originally posted by Emirena I'm very excited for the k1 mkII... I'm curious to test its performance on autofocus speed/accuracy and high iso noise.
Originally posted by Emirena jesus christ I totally meant the k3 mkIII. I KNEW it was APS-C!
I'm confused. Are you asking about the K-1ii (full frame sensor) or the K-3iii (APS-C sensor, like the K-70)?
If your only concerns about the K-70 were its low light performance and AF for moving targets, those are the very issues that are addressed with the K-3iii. If you get a K-3iii, the only lens you need right away is a replacement for the DA 18-135. The obvious answer to that is the DA 16-85 or the new DA*16-50 f2.8, although you might also consider a combination of the DA 15 Limited and DA 20-40 Limited. If that's out of budget, get another 18-135 or Sigma 17-70 C.
As for the full frame option, you are not too heavily invested in APS-C and you have some nice FF lenses, so the switch need not be too expensive. You could sell off the lenses that would not perform well on FF (see this article for advice on FF compatibility:
https://www.pentaxforums.com/articles/gear-guides/full-frame-coverage-of-da-lenses.html), like the DA 35 f2.8. (Are you talking about the DA 35mm f2.8 Limited macro, not the DA 35mm f2.4?) But if you are otherwise happy with APS-C, and have an interest in telephoto, what will you really gain from the switch? To put it another way, how is APS-C holding you back?
A cheaper option than either of these would be to get a KP (new if you can find one, otherwise second hand). I find its low light performance to be very good (shooting RAW and using decent software). Better tracking would be nice, but TBH developing your skills is a more effective way to get better results.
Originally posted by Emirena I want to buy a 400+ telephoto for birding but it's not a priority due to cost
For a longer AF wildlife lens, see the many other threads discussing the alternatives. Short answer: best option is either a 300mm prime (DA*300 f4 or F/FA*300 f4.5) and DA 1.4x TC, or DFA 150-450. A cheaper option would be a Sigma 150-500, 50-500 or 400 f5.6 tele macro. See the long lens thread (
https://www.pentaxforums.com/forums/122-lens-clubs/55946-300mm-plus-lens-clu...ng-lenses.html) for discussion and samples of the contenders.