Most (all?) old tele designs shared that "feature".
They can be a cheap solution, if you want to take portraits, but you'll get just a hint of softness, don't expect the "glow" shown by true soft-focus lenses, or the "swirliness" shown by petzvals (and some projection triplets) used beyond the intended format.
phfitz, do you want a shuttered lens?
If you can do without a shutter, or use a front-mounted one, there is some choice.
If you want a modern shutter, check first the dimension of a Betax No.5 flange. If it fits, shop for a Velostigmat Series II or an Ilex Paragon Series A, WITH soft-focus adjustment (most of them don't have it).
MOST "soft" and "portrait" lenses have no modern shutter AND are too big for your lensboard.
The solution could be a "landscape" meniscus of the right focal, which can be separated from its diaphragm.
You will have the choice to use the lens as-is, or wide open, and the size of the flange would be a perfect fit for a small lensboard.
If you want, you can supplement the lens with a small (= cheap) front shutter, like a Zettor, Luc, Silens, etc.
If you are patient, and shop carefully, you would spend 1/3 the cost of the most affordable soft-focus lens.
If you need more details, feel free to send me a PM.
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