You can vote anonymously.
Needless to say, feel free to elaborate your choice in the comment section!
Sigma has been rumored to have a 24-70mm f/2 DG design in the works since the early days of the Global Vision line.
Here are a few words about the ins and outs of such a lens.
Naturally the goal is to have a reasonably sharp lens wide open at all focal lengths and throughout the frame, which for a full-frame 24-70mm f/2 requires huge design efforts. Issues like field curvature would be very hard to keep at low levels. If high wide-open performance can only be achieved with 2 kg of glass, the lens is unlikely to see the light of day.
The pair of 150-600mm f/5-6.3 lenses offers a good example of size increase (and price increase, subsequently) due to a higher-performing design… while the aperture is the same for both lenses!
Reducing the range would put much less stress on the optics − and on the engineers. Thing is, a shorter range would be less appealing, especially compared to f/1.4 primes.
Eat the sales of the primes?
The main point for a 24-70mm f/2 lens is the versatility. One stop of extra light versus the primes (35mm f/1.4, 50mm f/1.4, and the future 24mm f/1.4) won’t be enough for some users to keep considering them. Carrying a single lens instead of three is attractive.
Of course there are reasons to favor one or several f/1.4 prime lenses over a 24-70mm f/2, including the better optics (to some degree: less field curvature, less distortion, less CA, better bokeh…), the need/want for f/1.4, the need/habit to use a certain focal length… But I’m not sure this would be enough not to cannibalize sales of the fixed-focal-length lenses in this range, at least to some extent.
A regular 24-70mm f/2.8 design would keep the primes safe, and is the safest solution for Sigma. Actually, it is the most likely option.
A rumor has it that the lens could be priced below the Canon 24-70mm f/2.8L II USM. This sounds unrealistic, to say the least.
See the price gap between the two Canon 24-70mm lenses. The 24-70mm f/2.8L II USM (regular price $2,099) is more than twice as expensive as the one-stop-slower 24-70mm f/4L IS USM ($999.99), and the latter would cost less without image stabilization… So how much for a 24-70mm f/2? Even if we’re talking Sigma, I can’t imagine the lens to sell for less than $2k.
In the end, a good balance between all the aforementioned factors has to be found, to make sure the market does not reject the product. Tough task.
So could it be the very unique lens that was talked about recently? I doubt it, but there is room for speculation.
Fake Sigma 24-70mm f/2 DG HSM Art