I got an Ultra Wide-Heliar 12mm f/5.6 Lens and a filter adapter and I tested this lens this lens last weekend. M-mount of Ultra Wide-Heliar 12mm f/5.6 has been released, but my lens is screw mount version. The screw mount version does not have a rangefinder coupling so I have to rely on eye measurement. However, the closest focusing distance of the screw mount version is 0.3m. M-mount version is 0.5m. This 20cm of difference is significant for such a super wide angle lens.
I got an Ultra Wide-Heliar 12mm f/5.6 Lens and a filter adapter and I tested this lens this lens last weekend. M-mount of Ultra Wide-Heliar 12mm f/5.6 has been released, but my lens is screw mount version. The screw mount version does not have a rangefinder coupling so I have to rely on eye measurement. However, the closest focusing distance of the screw mount version is 0.3m. M-mount version is 0.5m. This 20cm of difference is significant for such a super wide angle lens.
I did not buy this lens to cover wide area of view. That will be done panorama head. Instead, I bought this lens to enjoy its stretched perspective.

About 25cm awat from this horse Don’t lick my lens!

I did not want to lie down on ground so I just approached my camera to the closest flowers about 25cm away. I did not use a finder.