Originally posted by jatrax It is under non-SMC lenses: ...There are actually 3 versions of one of these lenses showing the changes and development over time:...At one time I had all three of the 28-80's together. I did a lens test and the SMC version was clearly the winner.
Thanks for that info. Looking more closely, here and on Ebay, it looks to me as if the main tell-tale is that the Takumars have a green aperture number scale and the SMCs have white. The SMC ones also seem to have "SMC" on the nameplate, but not all sellers' photo angles show that nameplate, while the aperture scale is more likely to be visible simply because it wraps round more.
It does look like the vast majority of the 28-80mm on Ebay are Takumars, I guess because they were often supplied in a kit than the SMCs. It is also obvious that most sellers (and buyers?) would not know the difference, as I did not until today.