I have a quick update on the 35 ART vs. 31 Ltd; I rented both lenses, and they just arrived about an hour ago. Some initial impressions:
1. Both are better lenses than I am a photographer
2. The AF in both is more precise than my 18-55 (noticed I may have a very slight front or back focus issue with the split-prism focus screen I installed)
3. The AF in the Pentax seems faster, but the silent AF in the Sigma is pretty cool
4. Edit: The quick shift feature on the sigma is nice.
5. The size difference is real, but I was expecting the Sigma to be a lot bigger. I've been shooting birds with an SMC 300m f/4, so both lenses seem manageable in comparison.
6. The 4mm focal length difference is more noticeable than I'd expected (not good or bad, just there)
I'll need to spend some more time playing with them this week.
Last edited by BugsDogsAndSunsets; 03-23-2019 at 07:46 AM.