Sigma PK 70-210 f2.8
September last year (though it doesn't feel that long ago) I got myself a new lens. Well, actually quite an old lens that was new to me. A Sigma Pentax-K mount 70-210mm f2.8. It was surprisingly cheap for an f2.8 tele-zoom: £120. I have a 135mm prime that I quite like, but often find I'm too lazy to swap to other lenses and end up with all my pictures being a bit samey. I figured having a zoom that crossed that 135mm might let me introduce a bit more variation.
I've now taken it out a few times and did get some pictures I'm happy with (and a lot that where the focus isn't even close).
All of those were with adaptor that just connects the different mounts. I have now got a .72x focal reducer that will make it a bit wider and faster. On my GX80 it'll be roughly equivalent of a 100-300mm f2 on 35mm. So far I've only had a few minutes to play with it, looking forward to getting out with it to have a longer play.
This takes me up to a dozen lenses that I can use with me GX80 - and only the kit lens that came with it has autofocus.
I have been thinking about getting a better camera. Micro 4/3 mostly haven't really moved on enough from the GX80 to be much of an upgrade. The GH6 would be a nice step up, but I don't much like the form factor. Or the price. I'm still hopeful Panasonic might make a GX camera with the sensor from the GH6, but there would probably be a fairly long wait before any would be available at a price I'd be willing to pay. Considering moving to another mount top of my list would be Fujifilm X-something or Sony A6000 series. There seems to be fewer options for adapting weird old lenses to Fujifilm X-mount than Sony E (or micro 4/3) - e.g. I couldn't find an equivalent of the Pentax-K focal reducer I just got for Fujifilm X, but there are a few options for Sony E. That has me leaning towards A6000 series - some of them are even old enough to be available at price I might be willing to pay..