If changing the position of the image circle mattered, you would have to refocus after shift and rise too, which you definitely don't (assuming a lens with a fairly flat field).
You're going to make me setup the camera to try now aren't you. :rolleyes:
Won't enough rise/shift change the distance between the film plane and the lens? Shouldn't that require a change in focus?
What's important for the rear standards is whether the axis of rotation lies on the film plane. If it doesn't, then any tilt or shift will require refocusing. Some center tilts, for example, do not pivot on the film plane. These will require more refocusing than others. Regarding front focus, I assume that this needs to be at the nodal point of the lens, and this will be slightly different with different lenses. On my Sinar P, though, I don't need to refocus when I tilt the lens, but maybe I my lenses have a similar nodal point. For example, I don't own any telephoto LF lenses, which is different from long focal length lenses.
You're going to make me setup the camera to try now aren't you. :rolleyes:
Won't enough rise/shift change the distance between the film plane and the lens? Shouldn't that require a change in focus?
No, it won't. The on-axis distance is constant (assuming your standards are straight - and a reasonably flat-field lens), and the rest is taken care of by the (aforementioned) flat field.
Just last week I took a shot with a 210mm Angulon on 8x10" film: First I focused on the subject, then I decided I wanted the framing a bit different and shifted the lens up by 20cm (on vertical 8x10" film, 20x25cm). The very top was soft since the lens isn't entirely flat-field outside of about 480mm image circle, but the rest was just as sharp.
Since I also happen to own that greatest of all "toys" for playing with shifts, swings, tilts, axis placements and internodal distances (the Carbon Infinity), I've played around with just about any conceivable movement and combination of movements, including changing the distance between pivot pint and lens nodes.