[Brightcolours]

f/1.2 is half stop faster, I thought. f/1, 1.4, 2, 2.8 is the row I have I mind. But of course, difference is tiny and marginal, and can easily be eaten up by different transmission values. SLR land really offers faster glass than f/1.2 at least in my mind: Canon 50/1.0 (so they CAN do faster lenses, lots of them...)

http://photo.stackexchange.com/questions...for-a-dslr
http://www.thephoblographer.com/2013/08/...l2kRsTGurU


And here is one f/0.95 for FF: http://www.meyer-optik-goerlitz.de/nocturnus-f095-50mm/ currently in production.


Don't want to split hair, but the choices are a bit more. And of course, all of them very exotic and only good for saying "it"s more fast glass around" 8)


Now, I agree, the 35L II is really a nice thing of glass and surely capapble to resolve far more than "only" 50 MP. In centre. The sheer numbers "35/1.4” to me remain asking "nice, but what IS better on it than on others of the same specs?"


And I don't only have Sigma 35/1.4 since two years or longer? But also replaced the Nikkor 24/1.4 against the Sigma art version which still gives more crisp and crunch. Depending of the distance and aperture, I also like the bokeh better. But that's predictable to read from my side.

f1, f1.4, f2, f2.8.. that row should teach you that indeed f1.2 is not exactly half a stop faster.  If f1.2 was half a stop faster than f1, and f1.4 a whole stop faster than f1, two stops faster would be f1.8.  and 3 stops faster would be f2.2. But things are clearly not linear.

F1.2 is not 1/3rd stop, nor half a stop. It is almost some arbitrary number, given to lenses a bit faster than f1.4. In practice, f-numbers are rounded, and at these low numbers the rounding error/margin has a relatively big impact. Most f1.2 lenses are not anywhere near half a stop faster, due to their too narrow mount losing a lot of light.

 

Rover points out that in the 35mm range f1.4 is about as fast as it gets for FF. It then makes little sense giving links to lenses not for FF, or lenses of a different focal length than 35mm on FF.