>>42820172:30 - i doubt this lens is that bad, i suspect he just has one with element separation, which is very common in some brands of this age. In some cases it's essentially impossible to find one that hasnt delaminated.
Figuring out how to look into a very-long-focallenght-very-short-physical-lenght lens isnt trivial, so almost nobody ever inspects the front element: and thats the mirror that usually delaminates.
Also; if the lens has drop-in filters (seen on the green sigma here) and it's not installed... the optics arent complete, and wont focus.
6:20 the sigma looks to be the ~60mm diameter version of the same lens I owned with a ~120mm diameter. They look so similar it can be difficult to differentiate them till you have them in-hand. (as i discovered when i bought the smaller version off ebay trying to find parts for my larger version) I imagine the smaller version was 'better' but darker; this means you need full, strong sun to use them at all or you cant really see through them well enough to focus. Either way they are a cheap lens, the design is like the roxon (iirc) et al, so not very good. Very light though.
The large diameter version, compared to a 1000mm
