Sigma 24-70 F2 OS

I think the "make it or brake it" for this lens would be whether or not it's decently sharp from F2 to F2.8 if it is then a lot of shooters won't mind the added weight for the extra stop of light, If it'll be not so sharp (for pros) then it'll be just a pain to drag it around
Just my 0.2$

Hopefully, with how Sigma has been doing with it's new releases, we will see an incredibly sharp lens if this lens comes to fruition. A bit heavy and might force people to buy some new gigantic filters, but I think the stop of light would be incredible.

As long as I can get laid more with this lens I'm down.

For me, i dont care about the size and weight. As long as its cheaper than canons offering and is atleast as sharp as canons lens when stopped down to 2.8, i am definately eyeing this one with eager eyes.

shinksma wrote in post #16165156
Scanning through the Tables of Lenses PDF files, I would hazard a guess that it is actually a good rule of thumb. In the cases where Canon has a pair of lenses at a given FL or FL zoom range but at different apertures, the weight gain from 2.8 -> 2.0 or 4.0 -> 2.8 is about double.

e.g. the 70-200 IS 4.0 760g, the 70-200 IS 2.8 II 1490g.

or the 300 IS 4.0 1190g, 300 IS 2.8 II 2350g.

or the 135 Soft-Focus 2.8 390g, 135 2.0 750g.

or 85 1.8 425g, 85 1.2 1025g.

And that doesn't even take into account the addition of IS/OS.

A slightly different comparison:

24-70 4.0 IS 600g, 24-70 2.8 II (non-IS) 805g. Without the IS the new 24-70 4.0 would probably have weighed 450g or so, in my estimation.

Anyway, IMHO the comparison is valid, and the rumored Sigma 24-70 2.0 OS would weight about 1400g to 1500g. And I'd probably buy one, assuming optics were close to Canon's 24-70 2.8 II, and price was south of $2K.

shinksma

frankchn wrote in post #16165295
Yup. Some more examples:

Canon 35mm f/2 IS USM - 335g, Canon 35mm f/1.4L - 580g
Canon 200mm f/2.8L - 765g, Canon 200mm f/2L IS - 2520g
Canon 400mm f/4 DO - 1940g, Canon 400mm f/2.8L IS II - 3850g

Of course, there is probably a base amount of material needed that won't change - explaining the smaller differences you see between the 24-70 f/4L and the f/2.8L. That said, I would be very surprised if the lens (if indeed real) is less than 1.2 kg or has a filter size of 86mm or lens with the same IQ is the Tamron 24-70 or the 24-70II.

You've picked lenses that support your claim, but omitted others that don't. You've also included some lenses that don't support your own claim. I wasn't trying to start an argument, just trying to point out that such a simple statement doesn't account for all the variables that go into the final weight of a lens. Your rule of doubling isn't universal enough to be a rule.

Nightdiver13 wrote in post #16165459
You've picked lenses that support your claim, but omitted others that don't. You've also included some lenses that don't support your own claim. I wasn't trying to start an argument, just trying to point out that such a simple statement doesn't account for all the variables that go into the final weight of a lens. Your rule of doubling isn't universal enough to be a rule.

Well, a rule of thumb isn't going to be strictly accurate or reliable in every situation under every tradeoff made by each of the lens manufacturers. However, it is a good approximation in a lot of cases -- including some zoom lenses of similar construction and in similar focal ranges. I will concede that the rule of thumb does work better than telephoto lenses than wide-angles such as the 17-40mm vs 16-35mm (telephotos have glass elements that scale with the aperture opening [I.e. Focal Length / Aperture] much better than wide angles).

I agree that there are a lot of variables -- build quality, the presence of IS, USM, etc... that go into the final lens weight. However, assuming that Sigma is targeting consumers who would otherwise buy the 24-70L, I personally don't think too much weight can be saved before the lens starts to feel cheap or compromised. Remember, bigger glass elements requires more structural support and bigger motors to move around as well.

That said, even if we assume that Sigma managed to only increase the weight by 35% (the difference between the 2.8 and 4 IS versions of Canon's 24-70), it will still put it at approximately 1,100g, which is pretty heavy for a standard zoom.

AND image stabilization? Take my money nao!

If this lens checks all the boxes I'll be in line on release day.

^^^
indeed a promising rumor - if it is true.
and if we aren't talking about a $4k lens!
i am not sure that I "buy" that the lens will come in at a price point under the canon version II

Sounds like absolute bull.

One stop bigger requires 1.4 times in linear dimension (diameter) for the aperture. Assuming all else equal (assume the 77mm front filter size of the 24-70 mark I), we are taking about a front filter size around 110cm? Really? For a walkaround? We haven't even think about the weight!

Sigma achieved this on the APS-C only because of the smaller sensor size and by severely restricting the focal range (making that almost like a pseudo-zoom or pseudo-prime). That thing is already huge!

For now I am assuming this is the wild imagination of someone jealous of the 18-35 for crop camera.

frankchn wrote in post #16165512
Well, a rule of thumb isn't going to be strictly accurate or reliable in every situation under every tradeoff made by each of the lens manufacturers. However, it is a good approximation in a lot of cases -- including some zoom lenses of similar construction and in similar focal ranges. I will concede that the rule of thumb does work better than telephoto lenses than wide-angles such as the 17-40mm vs 16-35mm (telephotos have glass elements that scale with the aperture opening [I.e. Focal Length / Aperture] much better than wide angles).

I agree that there are a lot of variables -- build quality, the presence of IS, USM, etc... that go into the final lens weight. However, assuming that Sigma is targeting consumers who would otherwise buy the 24-70L, I personally don't think too much weight can be saved before the lens starts to feel cheap or compromised. Remember, bigger glass elements requires more structural support and bigger motors to move around as well.

That said, even if we assume that Sigma managed to only increase the weight by 35% (the difference between the 2.8 and 4 IS versions of Canon's 24-70), it will still put it at approximately 1,100g, which is pretty heavy for a standard zoom.

I think this rule of thumb makes perfect sense. If you think about the key components being used in a lens, most of them are proportional to the surface area of the cross section. I can think of the barrel, the glass elements etc. Assuming there is no increase in the lens complexity, meaning no substantial change in the number of required elements or the length of the lens, then a doubling of the aperture -> doubling of surface area of each element -> doubling of the weight of each element -> doubling of the lens weight.

Nightdiver13 wrote in post #16165459
You've picked lenses that support your claim, but omitted others that don't. You've also included some lenses that don't support your own claim. I wasn't trying to start an argument, just trying to point out that such a simple statement doesn't account for all the variables that go into the final weight of a lens. Your rule of doubling isn't universal enough to be a rule.

I honestly started with your opinion of the matter, looking at the Tables of Lenses to find the "typical" example and expecting it would show maybe a 25-40% increase. The only time weights are similar or within 40% is when the lenses are from different manufacturers and the should-be-heavier lens is made by a not-exactly L-quality manufacturer (e.g. Vivitar), or if the lenses are a different beast - the 100mm 2.0 vs the 100mm f/2.8 macro - the macro capability seems to add weight to every example I could find.

So I'm not trying to start/continue anything either, just data mining, and finding that the rule of thumb does indeed reflect the data, and it makes sense based on the physics of the matter - bigger glass, heavier motors, etc, as pointed out.

If you have some alternative examples I'd appreciate it - might be interesting.

shinksma

I can't see a f/2 zoom lens with a 3X zoom range...

SMP_Homer wrote in post #16166455
I can't see a f/2 zoom lens with a 3X zoom range...

I can't see the logic at all, 24-70mm is a 100% walk around focal length range, but the lens will likely be huge and heavy, so who's it for? Would anyone really honestly take a 1.5kg standard zoom along for whatever?

It better be super sharp at f/2 as well, or again there is no point, when I could just use a prime instead, or use a smaller aperture (and thus may as well use a smaller lens altogether).

Enough people complained about the Brick's weight as it is.

A friend of mine who works at NASA, his boy has a friend on his baseball team who gets babysitted by this lady who has a nephew in florida that does top secret testing for the Sigma antartica team. He has been using this very lens for the past 4 years. It only weighs 5.3lbs but is filled with helium to reduce the "realistic weight" making it the same as a 40mm pancake.

Ya, this is more accurate lol.

Kolor-Pikker wrote in post #16167016
I can't see the logic at all

the reason I can't see a f/2 with a 3x zoom is you don't see much in the way of a 2.8 zoom with more than 3x range
I always assumed technical reasons for lack of anything substantially more than 3x in a 2.8, and whatever those tech reasons are, will be magnified in a 2.0 zoom... i would be happy with a 24-48 (or call it 24-50 or whatever) in 2.0, but I really doubt we will see long 2.0 zooms...