Is this an uncroped APS-C frame? The Heligon seems to perform marvelously on the relatively large sensor and at distance.
Yes. The field is very flat and apart from some mild blue fringing on high-contrast transitions, the rendition is very smooth with high sharpness.
The 100 Rodenstock will almost cover the 24x36 FX format at infinity focus, but the corners disclose the format exceeds the circle of acceptable image quality. On the Z fc, there is no such issue. The focusing helicoid I put on the 100 Rodenstock allows focus from approx. 80 cm to infinity with the Z cameras, but of course I can add extension if closer focus is desired.