Originally posted by Smolk Yes, but that's not keeping up like for like, that means being at a disadvantage. A sharp lens that costs 200 or 1000 makes a difference. Although it depends on the full specs, and character, of the lens in the end.
True but optically speaking, I think DSLR lenses can keep up nicely. The latest Star Pentax lenses are quality.
That said, once you factor in size and weight it becomes another story, as I mentioned. And it becomes difficult physically to go below f/1.4 it seems on DSLRs where as with a larger mount diameter and shorter flange, we'll see the addition of much faster glass (at the expense of size, weight, and price!).
But how many really need sub f/1.4 glass? It becomes a niche within a niche for most imo.
Price, as you also mention, is the other big factor. Even if I could warrant 8 grand for a 58 f/0.95 I'm not sure I'd buy it. The difference between it and the photos at f/1.2 or f/1.4 are fairly minimal. And it becomes more difficult to focus at such shallow depths. Seems more like status symbol lens for most applications.
I want to see more lenses like the Tamron 70-180 f/2.8 lens. It's as small and light as a DSLR 70-200 f/4 style lens but a stop faster.
Maybe something such as a 50-105 f/2.0 would be nice. I hope lens makers get more creative with their designs, taking functionality and dimensions in mind.