Rod writes up the SP 70-150 Soft Focus on ‘Couv’ Camera.
Many moons ago Tamron made a zoom lens with soft focus control and it was quite the lens. They were not the first soft focus lens and they certainly were not the last, but they are the only quality zoom lens with the creative soft focus control I have ever seen. The lens is quite rare as Tamron only produced the lens from 1979-83 and it was a low production unit.
I spent a few years ‘Jonesing’ for the lens bidding on them at ebay and searching tables at camera shows like PhotoFair. I never found one I could justify the price on until I ran into a Canadian who had one that was broken. The soft focus actuation ring was stuck and the aperture diaphragm was a little wonky. So I picked it up on the cheap and promptly had it repaired. These things routinely fetch north of $400 and now I know why.
The lens is a Tamron Adaptall-2 SP 70-150/2.8 Soft Focus. With the soft focus turned off it is a very sharp lens wide open, throughout the focal range. It has three variable softness settings each getting stronger. Even on the third setting it doesn’t feel overdone like some soft focus lenses. My biggest complaint about the lens is the weight, it is heavy beast. Tamron SP lenses in the Adaptall era were pretty stoutly built and this lens is no exception.