jeffa4444 said:
In terms of a constant maximum aperture set of lenses Canon has fallen behind Sigma and one has to wonder why.
This is Canon current offering:-
EF 24mm f1.4L II
EF 35mm f1.4L II
EF 50mm f1.4 (A lens not up to the newer 5D MKIV, 5DS / R cameras resolution)
we have a rumoured EF 85mm f1.4L
Now lets look at a constant maximum aperture selection from Sigma Art series
20mm f1.4 DG HSM A
24mm f1.4 DG HSM A
35mm f1.4 DG HSM A
50mm f1.4 DG HSM A
85mm f1.4 DG HSM A
Sigma has the 135mm f1.8 DG HSM A which obviously is not a constant maximum aperture lens and is missing a 100mm from the Art series. Nikon recently produced a 105mm f1.4E ED so its plausible to make a lens in numbers at this aperture and maintain high quality. In cinematography a number of companies make fast primes with constant maximum apertures and for the video shooters among Canon clients this is a holy grail they are yet to realise from Canon current portfolio.
The mystery is the lack of EF 50mm f1.4L, this is the easiest focal length to design and would sell in greater numbers yet to date Canon has not delivered. Moreover its unlikely to unseat the 50mm f1.2L because they can be designed with different criteria (i.e. soft & creamy at max aperture for the 1.2 and crisp & contrast for the 1.4).
Sigma has taken their 1.4 lenses and repurposed them for cinematography to a part of the market that cannot afford Zeiss, Cookes, Schneider, Leica etc. Canon fixed cinematography primes are a mixed bag with good & bad lenses and not widely popular as a result.
So Canon where is the EF 50mm f1.4L and the EF 85mm f1.4L and what else beyond that because that would still only give you four focal lengths you would need either a 18 / 20mm and a 100mm
What exactly are you meaning by "
constant maximum aperture" by which a 135A does not count? Do you really mean "f/1.4"? Because primes are constant maximum aperture by default and definition: they don't have a zoom range over which maximum aperture can change. I assume "at least f/1.4" is what you mean, because Canon has a ton more primes than you listed, and the only reason I can think of you've excluded them is they aren't f/1.4.
I would say that, as a strategy, Sigma has done a great job of identifying weak spots in the Canon lineup and focusing their efforts there. A full library of f/1.4 primes (plus the 24-70/2.8OS), is a soft spot in Canon's lineup. The 24-105A is much less of an unserved market, so whatever people say about the Sigma being better than the old 24-105L, I'd be really curious what the sales numbers have been for the Art, and how it's worked out for them as an investment.