I could have chosen the Olympus OM-1 camera together with the M.Zuiko ED 300mm ƒ4 IS PRO which also is a 600 mm lens - and 1.3 stops brighter. It should have given me same or (theoretically) slightly better quality (if i would been able to exactly set the focus manually) I've used this combination before.

However I chose wanting to go with flexibility, so i chose the big Sigma zoom instead. Plus as i mentioned earlier; i wanted to use that lens outdoors, because I have never done that.

(Yeah, I sometimes tend to be late with things I have planned or bought... Quite some time can pass until i actually use them). Same thing happened for example with the M.Zuiko ED 90 mm [180 mm] ƒ3.5 IS PRO Macro lens. But once I use a lens (or other photographic tool), i really use them quite a lot.

I am not sure, if a different lens (in my arsenal) would have made better sense. I could have used the Canon EF 300/4 L IS lens, or why not that manual old Russian mirror lens whose name i don't know; it is a 500mm ƒ6.3 lens. However, I don't have any T2 adapter to use it on a EOS RF mount camera. It is surprisingly sharp - but like as with any other super telephoto lens; manual focus is always tricky in darkness / with dark subjects during twilight.

Sharpness of the Sigma Sport 60-600 mm lens

It ain't super telephoto quality - but it is still damn sharp, especially given that this is a pretty extreme zoom lens. It also a tiny notch better than the Tamron or the Sigma 150-600 mm. At 60mm however you can spot some color fingring. I see the 60 mm focal length just as a nice way, being able to catch a wider images, without having to switch lens. And then go all the way up to 600 mm - which is pretty cool when I think about it.

Now i do apply slight AI sharpening - and the fine details chisel out excellently. So, i do recommend that treatment - because it really pulls out even the finest details in distant objects - pretty much close to the level of the best top-notch super telephoto lenses !