Patent: Canon EF 28-560mm f/2.8-5.6
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Small is relative, but it has been possibile to minimize lens size for consumer lenses where they were not built like a tank. The patent refers over and over to small lens size, below are a couple of quotes.
So... I could just leave it attached to a SL-1 and carry it around in my camera bag ;D
From the Patent
"In recent years, the imaging optical system used for an imaging device is required to be a highly efficient zoom lens by the high zooming ratio, though the whole system is small. It is requested that a focus is made to these zoom lenses at high speed and with high precision etc."
"The present invention aims at offer of the imaging device which has the small zoom lens and it from which a quick focus is easy, and it is a high zooming ratio, and high optical performance is obtained covering the object distance all the zoom ranges and at large."
And --- Its a Macro Lens too:
"the miniaturization of the whole lens system becomes easy. Close photographing, especially pole close photographing become easy. Since the small lightweight lens group is moved, the driving force of a lens group is small, and ends, and there are the characteristics, like a quick focus is made."
So... I could just leave it attached to a SL-1 and carry it around in my camera bag ;D
From the Patent
"In recent years, the imaging optical system used for an imaging device is required to be a highly efficient zoom lens by the high zooming ratio, though the whole system is small. It is requested that a focus is made to these zoom lenses at high speed and with high precision etc."
"The present invention aims at offer of the imaging device which has the small zoom lens and it from which a quick focus is easy, and it is a high zooming ratio, and high optical performance is obtained covering the object distance all the zoom ranges and at large."
And --- Its a Macro Lens too:
"the miniaturization of the whole lens system becomes easy. Close photographing, especially pole close photographing become easy. Since the small lightweight lens group is moved, the driving force of a lens group is small, and ends, and there are the characteristics, like a quick focus is made."
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Jack Douglas said:
The diameter of the front element is (approximately) the focal length divided by the aperture.
Thus a 560 / 5.6 = 100mm. A 300 /2.8 ~ 100mm. Same diameter.
The definition of the F stop is the focal length of the lens divided by the maximum diameter of the aperture when opened fully.
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sjprg said:
You are assuming a "L" lens. Its likely a consumer lens to compete with the Tamron and Sigma lenses.
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RGF said:
Not exactly. The f stop is the focal length over the entrance pupil diameter, not the actual aperture diameter. The entrance pupil is the image of the aperture from the objective side; it is the image of the opening that can be magnified by the optics.
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Wizardly said:
I'd argue the f stop is the focal length over the apparent size of the entrance pupil diameter. But even if we quibble over technicalities the optical fact remains that the aperture can't be larger than the front element because it can't appear to be bigger than that, ergo the focal length divided by aperture will give you a minimum front element size.
If you can point me to a lens that has a front element smaller than its focal length divided by its actual fastest aperture I'd like to see it.
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I see no reason for such a lens to exist unless Canon has found a magical new design method to ensure superb image quality throughout this zoom range. And if that really did happen, this lens would cost too much. The old 28-300 was a dud. Will this be any better? We'll have to see.
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Why are only the zoom updated? :'(
With such a lens you just carry around more kilos.
Common canon.
I would like to see much more the update of 300mm 4l IS or 400mm 5.6L to IS.
With such a lens you just carry around more kilos.
Common canon.
I would like to see much more the update of 300mm 4l IS or 400mm 5.6L to IS.
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neuroanatomist said:
A 28-300 is a 10.7X zoom
Are you trying to demonstrate that you can't do math Come on Neuro..... this is overkill.... You don't have to pick on everything he posts.... you are better than this.
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L
Loswr
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Don Haines said:neuroanatomist said:
A 28-300 is a 10.7X zoom
And a 28-560mm is a 20x zoom.
Are you trying to demonstrate the definition of the word 'sometimes'? Actually, a 50% correct rate is better than average in this case.
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Tamron makes a 16-300mm (18.8X) zoom lens for crop cameras. It is a very popular lens and sells quite well. Although the image quality suffers with such a wide range, for many people the convenience of just having the single lens seems to out-weigh the drop in IQ.
Now a 20X zoom? ? ? about the same ratio so it can obviously be done without killing the IQ..... but here we are talking about 560mm at the far end instead of 300m, and we are talking about F5.6 instead of F6.3. This will be a large heavy beast and that is going to mitigate a lot of the convenience of having a single lens. For example, I have the Tamron 150-600 and that should be roughly the physical size of this lens (actually a touch smaller) and as an 188cm tall person who carries canoes through the woods I find it to be a heavy and awkward lens. This isn't a walk-around-all-day-with-it-hanging-off-the-camera-strap kind of lens, and that is going to limit the market of potential buyers....
In the end, I think that this is a "look what I can do" type of product and will never see the mass market.
Now a 20X zoom? ? ? about the same ratio so it can obviously be done without killing the IQ..... but here we are talking about 560mm at the far end instead of 300m, and we are talking about F5.6 instead of F6.3. This will be a large heavy beast and that is going to mitigate a lot of the convenience of having a single lens. For example, I have the Tamron 150-600 and that should be roughly the physical size of this lens (actually a touch smaller) and as an 188cm tall person who carries canoes through the woods I find it to be a heavy and awkward lens. This isn't a walk-around-all-day-with-it-hanging-off-the-camera-strap kind of lens, and that is going to limit the market of potential buyers....
In the end, I think that this is a "look what I can do" type of product and will never see the mass market.
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and a 50% correct rate beats weather forecasters, who are wrong 117% of the time.....neuroanatomist said:Don Haines said:neuroanatomist said:
A 28-300 is a 10.7X zoom
And a 28-560mm is a 20x zoom.
Actually, a 50% correct rate is better than average in this case.
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Not to mention the global climate forecasters?
Neuro, I'm curious if this is a gradual long term disdain or has there been a specific issue. In roughly a couple years plus, I get the gist of the problem, but why so persistent? It would strike me that a response is a waste of energy that could be directed elsewhere. The correction of misguided information is valuable but .....
Jack
Neuro, I'm curious if this is a gradual long term disdain or has there been a specific issue. In roughly a couple years plus, I get the gist of the problem, but why so persistent? It would strike me that a response is a waste of energy that could be directed elsewhere. The correction of misguided information is valuable but .....
Jack
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RGF said:
Yes it's a general rule which I use too...but this isn't a 560mm...the patent is for a 540mm. Which brings the objective lens down a bit to 96mm.
If we are looking at a lens with an approximate from element of say 100mm...this lens isn't going to be much cheaper than the current 300mm f2.8 LIS II. I also don't understand the need for another 200-400 +integrated 1.4x TC lens...that's already covered very well with the 200-400 LIS.
I suspect that this is a 28-540mm f5.6-f8 lens. Giving a front optic of around 67mm and making it squarely in the consumer market.
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privatebydesign said:
The patent gave the dimensions of the front element. 1.9 mm thick with curvature radii of 114 mm on the front and 230 mm on the back. The front element should only be 60mm, no?
I'm trying to understand this phenomenon myself, but conceptually I understand it to mean that the elements in front of the aperture are causing the rays to converge towards the aperture so that the image of the aperture is larger than the front element; if you were trying to see the aperture you would have to angle the lens away from your eye to see the edge.
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