More Sigma Primes Coming? [CR1]

[neuroanatomist]

Yes. In practice you'll end up with a 77 mm filter.
Canon's 135/2 has a filter size of 72 mm. Same as the 200/2.8

135 divided by 2 is only 67.5mm, with the barrel thickness, they end up with 72mm filter size
135 divided by 1.8 is already 75mm of opening, + barrel thickness, i don't think 77mm (+2mm) can do, thats diameter, not radius

It probably could, the barrel is not thicker than 1 mm (so 2 mm added to the diameter). But it depends more on the optical design of the lens - my guess is that a larger diameter front element will be used to reduce vignetting, and an 82mm filter will be the result. More lenses are coming with 82mm filters these days (Canon 16-35mm II, which I'll point out increased in diameter from the 77mm filter used on the MkI version of that lens), the TS-E 24mm II (and the MkI version of that lens used only a 72mm filter!).

In that regard, I really hope B+W comes out with an 82mm ND 3.0 (10-stops) - well, I've been told that they will not, but their parent company, Schneider Optics, might...

 

[Bob Howland]

... and I think Sigma would do well to spec a 135 mm prime at f/1.8

that would require filter size in the 8xmm size

Wouldn't 75mm suffice ?

Yes. In practice you'll end up with a 77 mm filter.

Canon's 135/2 has a filter size of 72 mm. Same as the 200/2.8

135 divided by 2 is only 67.5mm, with the barrel thickness, they end up with 72mm filter size
135 divided by 1.8 is already 75mm of opening, + barrel thickness, i don't think 77mm (+2mm) can do, thats diameter, not radius

Nice try but 200 divided by 2.8 is 71.4mm and, as previously stated, the Canon version uses a 72mm filter

 

[nounours18200]

I hope Sigma update their 500mm f4.5 to be a true f4. The additonal OS system would be sweet but the real fun with a 500mm begins with a 1.4x TC...which would still AF well with an f4 design.

Me too: a supertele at a good price would be a best seller, but only if it is at a similar level of quality than the Canon 500/4... And this is maybe not a (so) easy challenge, because the level of quality to be reached is high, and the volume of sales not as high as for a basic 50mm...

The current Sigma 500/4.5 has two "problems" compared with the Canon 500/4 IS (not talking about the recent II version): it offers only f/4.5 so no AF when used with a x1.4TC and a non 1D body, and secondly its quality is not as high as the Canon... Despite its lower price, it is not enough to seriously challenge Canon on this top-class telephoto market .