So, just to be sure, you made this with the PL12-60 2.8 or the P12-60 3.5?In an earlier post mention was made of the Zomei 0.45x converter on the PL12-60mm, and the amount of vignetting seen in the RAW file when used at the 12mm end. I tried the 0.45x as well, but ended up settling on the Digital King 58mm 0.7x instead. That eliminated any issues with step up rings. There is still a small amount of vignetting in the RAW file, which is not there in the jpg. I suspect that it is because the jpg file (as seen in the file info on my GX8) is slightly narrower than the RAW file in terms of pixels. I am impressed with what can be achieved with the Digital King 0.7x. Especially since it still produces a sharp image at the long end of the 12-60mm, which gives you 42mm with the converter attached. Out of interest, the same converter used on the PL 14-140mm f3.5 is only good up to about 25mm on the zoom ring. After that the image becomes blurry. It's however worth walking with the converter to use on the 14-140mm in case you do need to go wider than 14mm but don't have a 7-14mm or similar wide angle zoom.
This is the jpg version of a shot of the PL 12-60mm with the Digital King 0.7x fitted. I posted the full image instead of a crop in case anyone wants to inspect it to see if the Digital King 0.7x would be a welcome addition to their kit.
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