The fourth 24 2.8 was an impulse buy... I had the opportunity to get a Tokina 24 2.8 for 14 dollars shipped so I just jumped on it!
It's identical and construction to the Vivitar (Cosina) so I wonder if it's a collaboration between Cosina and Tokina, like the 19-35 3.5-4.5 lenses from both that seem to have identical optical formula and just have different lens casing. But in these 24 2.8 lenses, even the fonts used to write on the lens bodies were the same!
The Tokina does focus closer though, and for some reason, even though they render very similarly and the Vivitar/Cosina might be hair sharper, I just enjoy shooting with the Tokina a bit more.
The fact that it looked unused (NOS) didn't hurt, either. What did hurt a bit is that it had a Ricoh pin and when I removed it, by accident I made it a declicked lens and couldn't find the tiny plastic pieces that would have made the aperture cling click again. Oh well, the A setting still works fine!
MFD, uncropped.