unfocused said:
privatebydesign said:
...Again, as I keep saying, I see no reason why Canon couldn't make a lens to compete with Tamron and Sigma for price in the 150/200-600 zoom range (the 100-400 MkII already does for the IQ), but if they do it will not be an L lens and it won't be f5.6, and both of those attributes have been stated in the rumour.
I'm not sure we are that far apart.
It sounds like we are both very skeptical that this lens will materialize as predicted.
You seem absolutely certain that Canon cannot (or perhaps will not) produce an affordable f5.6 200-600mm zoom because the front element would need to be 107mm (your number, correct?) I note that the Sigma sport is just 2mm smaller at 105mm and sells for $2,000 MSRP. I am not sure I understand why you feel so strongly about the size of the front element, especially since Sigma has produced two nearly identical lenses with the same zoom range and maximum aperture -- one using a 105mm filter and the other using a 95mm filter. This makes me suspect that the front element diameter might not be as rigid as you believe. Nor, do I understand why you feel this front element diameter is the deciding factor in the cost of a lens. Still, I'll happily yield to your technical knowledge on this as I am no lens designer.
On the other point, that it will not be an "L" lens, I don't understand your reasoning at all. It's not as though the "L" designation has any real world meaning. An "L" lens is simply whatever Canon chooses it to be. It does not need to be weathersealed. It does not need to be a constant aperture. It does not have to meet any objective standards for sharpness or anything else. It simply has to have a red ring around the front of the lens and if it is a telephoto, it must be painted white-ish.
It seems to me that my logic on the "L" designation is much more solid -- Canon can charge more for a lens if they call it an "L" and since this is not going to be a cheap lens anyway, they will call it "L" and take advantage of the perceived value that comes with that designation.
Alternatively, I am certainly willing to believe that a 200-600 "L" f5.6 would not be slotted in as a competitor to the Sigma Sports Zoom or the Nikon 500 zoom. It is entirely possible that instead it would be offered as an alternative to the 200-400 f4 with 1.4 extender zoom and priced accordingly. I don't take that personally and don't feel as those Canon would somehow be slighting me if that occurred. In fact, from a purely selfish standpoint, it would save me a considerable amount of money and keep me content with the 100-400 II and the Sigma Contemporary 150-600 zooms.
My wife will probably send Canon a thank you note for not producing an affordable 200-600 zoom.
I am no lens designer, I am just looking at the current and historical price point of Canon lenses with a similar or scalable specs. The FD 150-600 f5.6 L lens was a very expensive lens at the time and even now isn't cheap, why should a current version be cheap when no data supports that hope.
The entry pupil of a lens, that is the apparent size of the aperture, is determined by the focal length divided by the aperture, the front element must be bigger than that as the apparent aperture can't be bigger than the tube it is contained in, ergo, a 600mm f5.6 = 600/5.6 = 107mm. That is the diameter of the actual clear glass, not the size of the front of the lens.
The Sigma's are 600mm f6.3 = 600/6.3 = 95mm, the C lens isn't a true 600 and it isn't a true f6.3, the S lens does a little better, but I'd bet it isn't a true 600mm lens either.
As for the "L" designation, Canon have previously made some claims for them though as you say, it truthfully is more a marketing term. But previously they have stated that L lenses must have some exotic glass and or ground aspheric elements, since the introduction of weatherproofing they are supposed to include
"the most rugged and high quality build and weathersealing" and they have to fit and work on every EOS camera ever made, I got this from one of the Canon Lensworks books but can't remember which one.
Sure they could slip in a low end L lens, but what marketing value would that have in the longer term? Canon have no problem selling various $8,000 - $12,000 lenses for EOS cameras, and many considerably more expensive lenses for video users, why would they turn that all around to make a complex lens for a niche market? To me that makes no business sense.
If Canon make a 150-600 f5.6 L lens it will cost in the $10,000 region. Why would they do that when they have the 200-400 f4? Video, the 200-400 has to slot in the TC to get it to 560 and f5.6, don't forget that 200-400 f4 is, effectively, a 280-560 f5.6 that costs nearly $10,000, how are they going to do that for 20% of the price?
I am quite sure that if they make a $2,500 150-600 it will be an f6.3 max and won't be an "L" lens.
But, apart from the physics, I could be wrong, it's just that nothing in the present or past support the notion of a 150-600 f5.6 L being anything other than a premium priced lens.