I thought, and may well be wrong that the HCD 24mm, HCD 28mm and the HCD 35-90mm lenses could not be used on the H1 for example with a film back because of coverage. Now apparently the H5X allows those lenses on a film back.
Was the limitation physical or firm/software and what has changed in the H5X that can't be changed in the H1 to allow those lenses?
HC
D lenses cannot be used on the H1 camera, the camera will lock up. On a H3D, which was the only H camera that took digital and film backs until recently, they cannot be used with a film back, but can be used with a digital back. The reason is that the HC
D lenses are computed for a reduced image circle, the "D" stands in for digital. Other lenses are called HC, without the "D".
From the H4D-60, Hasselblad has had a back with a frame size as big as the film back window. The H4D-60 will automatically crop the area with HC
D lenses, but that function can be disabled. Then Hasselblad warns you that you may get vignetting and fuzzy corners from the smaller image circle of these "D" lenses.
Then Hasselblad introduced the H4x and, now, the H5x models. On these cameras, the HC
D lenses can be used. They will obviously exhibit a bit of vignetting and fuzzy corners, as they did on the H4D-60. It is not a big deal, simply crop to the image circle. Photographers actually using the lenses (as opposed as people simply reading about them on the Internet...) find them to be great even under these conditions. The HCD28 in particular is really, really good. The HCD24 is quite useful on the HTS system. The HCD35-90 zoom image circle will extend to film size from about 40mm onwards, compare that to the Schneider 40-80mm...