Curator Mary Child’s cousin from Sweden is familiar with the lens on John Tillman’s Home Portrait camera. He had this to say about it:
Wollensak’s Velostigmat Series II is a Tessar formula lens introduced about 1909 and were manufactured until just after WWII. There are three lens elements of which one consists of two glasses glued together according to the Tessar patent. It is sharp and seems has a diffusion attachment for soft focus which is used especially in portrait photography. The optics are for 5 x 7 and 5 x 8 negative plates. The lens is fast and modern. Today’s lenses are no faster.