# EF 300 f/4L IS II Patent



## Canon Rumors Guy (Feb 14, 2011)

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A patent for a 300 f/4L IS II has been filed in Japan. Remember, patents donâ€™t always become real products.</p>
<p><strong>Patent Publication No. 2011-27864</strong></p>
<ul>
<li>published 2011/02/10</li>
<li>filled 2009/07/23</li>
<li>Embodiment 1</li>
<li>focal distance f = 294.00mm</li>
<li>Fno = 4.14</li>
<li>angle of view 8.24 degrees</li>
<li>image circle 43.28mm</li>
<li>lens length 245.03mm</li>
<li>back focus 86.14mm</li>
</ul>
<p><strong>The Camera Shake:</strong></p>
<ul>
<li>The shake by a human is around 0.1-10Hz (low frequency).</li>
<li>The shake by a tripod is around 4-35Hz.</li>
<li>The shake by an in-vehicle camera is several Hz â€“ around several hundred Hz (high frequency).</li>
<li>The conventional camera shake revision cannot revise a shake of the high frequency.</li>
<li>Because the shake revision revise a shake by mechanical movement.</li>
<li>The electro-optic effect supports movement of 100Hz or more kHz.</li>
</ul>
<p>  </p>
<p><!--more--></p>
<div id="attachment_5947" class="wp-caption aligncenter" style="width: 578px"><img class="size-full wp-image-5947" title="2011_27864_fig02" src="http://www.canonrumors.com/wp-content/uploads/2011/02/2011_27864_fig02.png" alt="" width="568" height="234" /><p class="wp-caption-text">EF 300 f/4L IS II</p></div>
<div id="attachment_5948" class="wp-caption aligncenter" style="width: 410px"><img class="size-full wp-image-5948" title="ef300_4l_is_usm" src="http://www.canonrumors.com/wp-content/uploads/2011/02/ef300_4l_is_usm.png" alt="" width="400" height="270" /><p class="wp-caption-text">EF 300 f/4L IS (1997)</p></div>
<p><strong><span style="color: #ff0000;">c</span>r</strong>
```


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## KWSW (Feb 15, 2011)

Nice... and there I was thinking about picking up the current 300 f/4L for my 7D to shoot the local football/soccer league from the stands...


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## DJL329 (Feb 15, 2011)

KWSW said:


> Nice... and there I was thinking about picking up the current 300 f/4L for my 7D to shoot the local football/soccer league from the stands...



Like CR said, just because there's a patent, it doesn't mean it will ever become real. Even if it does, it could take years before it's released.

If you are serious about this lens, get a used one. Try the Buy & Sell forum on fredmiranda.com. I've seen them going for $900.


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## Justin (Feb 15, 2011)

Sure, why not. It's due for a refresh along with the 400 5.6.


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## Admin US West (Feb 15, 2011)

This lens has elements whos refractive index is controlled electrically. Its not a conventional lens by any means. I have no idea as to the practicality of mass producing them, but, it is a very interesting idea, one that we all have hoped would come.

Although it gives a 300mm f/4 lens as a example, it is a new type of IS that might appear in any lone telephoto lens. Perhaps one of the new super teles.

http://www4.ipdl.inpit.go.jp/Tokujitu/tjsogodbenk.ipdl


* NOTICES * 

JPO and INPIT are not responsible for any 
damages caused by the use of this translation. 

1.This document has been translated by computer. So the translation may not reflect the original precisely. 
2.**** shows the word which can not be translated. 
3.In the drawings, any words are not translated. 


--------------------------------------------------------------------------------
CLAIMS 

--------------------------------------------------------------------------------
[Claim(s)] 
[Claim 1] 
It is an optical instrument which has an optical system, 
A shake detection means which detects deflection, 
*An electro optics element which constitutes said a part of optical system and from which internal refractive index distribution changes with the electro optic effects according to voltage impressed,  * An optical instrument having a driving means which impresses voltage to said electro optics element so that an image shake by deflection detected by said shake detection means may be reduced. 
[Claim 2] 
The optical instrument according to claim 1, wherein refractive index distribution inside said electro optics element is unsymmetrical to an optic axis of said optical system. 
[Claim 3] 
The optical instrument according to claim 1 or 2, wherein said electro optics element shows the secondary more than electro optic effect. 
[Claim 4] 
An optical instrument of any one description of three from Claim 1, wherein this optical instrument has a vibration control means for reducing an image shake by deflection detected by said shake detection means apart from said electro optics element. 
[Claim 5] 
An optical instrument of any one description of four from Claim 1 having a photosensitive element which records an object image formed of said optical system. 


--------------------------------------------------------------------------------
[Translation done.]

â€¢Patent publication number 2011-27864 
◦Publishing, Feb 10, 2011
◦Filing, Jul 23, 2009
â€¢Implementation example 1 
◦Focal length f=294.00mm
◦Fno=4.14
◦8. 24 Â° Angle of view
◦Image circle 43. 28 mm
◦Lens length 245 mm
◦Back focus 86. 2 mm
â€¢When shooting in runout 
◦Human image stabilizer is approximately 0.1 to 10 Hz (low frequency)
◦Of a tripod is 4-35 Hz
◦Number of Hz etc vehicle camera-several hundred Hz (high frequency)
â€¢For the image stabilizer of the conventional correction technology in mechanical movement, high-frequency fluctuations and cannot compensate
â€¢Electro-optic effect if 100 Hz-kHz up to meet
â€¢Patent technology 
◦High-frequency blur to correction
◦Using electric Optics (electro-optic crystals)
◦Vary depending on voltage (electric) refractive index (electro-optical effect)
◦Asymmetric distribution of refractive optical axis.


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## /dev/null (Feb 15, 2011)

It is possible that they have found a material where the Kerr effect or Pockels effect is large enough to be useful.

http://en.wikipedia.org/wiki/Kerr_effect

http://en.wikipedia.org/wiki/Pockels_effect

However, chances are that such an IS will be very very power hungry. 

God only knows how to avoid CA in such a system.


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## GMCPhotographics (Feb 15, 2011)

Like CR said, just because there's a patent, it doesn't mean it will ever become real. Even if it does, it could take years before it's released.
[/quote]

True, but this patent was filled over a year and a half ago. It's only just become public, which is how we know about it.

From the optical block diagram, its looking very simular to the existing model except for this new EIOS system.


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## kubelik (Feb 15, 2011)

whether or not we see the electronic gizmos, this lens would be a good one to update in the next couple of years. given the optical quality of the existing 300 f/4 L IS, I have no doubt its successor will be frighteningly sharp


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## neuroanatomist (Feb 15, 2011)

Personally, I hope the 400mm f/5.6L gets updated first...


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## kubelik (Feb 15, 2011)

neuroanatomist said:


> Personally, I hope the 400mm f/5.6L gets updated first...



I really hope they change that one to a 500 f/5.6 L IS ... that would be a hotter item than a themos full of lava


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## kubelik (Feb 15, 2011)

dilbert said:


> kubelik said:
> 
> 
> > neuroanatomist said:
> ...



yes, but not prohibitively so. adding IS to the 400 f/5.6 is bound to up its weight already anyway. meanwhile there are Sigma zooms that go to 500mm featuring OS that weigh in under 2 kilos; I don't think there's any reason a canon 500 f/5.6 L IS prime lens should be any heavier. 1900g for a tack-sharp 500mm lens would be very exciting for a lot of people. the new 500mm f/4 L IS II, despite its major weight reduction, still comes in at over 3 kilos. it's a world of difference


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## lol (Feb 15, 2011)

I'll be really interested to see what the electro-optical component does! Just hope is it more affordable and useful than diffractive optics proved to be in practice.



kubelik said:


> meanwhile there are Sigma zooms that go to 500mm featuring OS that weigh in under 2 kilos; I don't think there's any reason a canon 500 f/5.6 L IS prime lens should be any heavier.


Sigma uses a trick of making their 50-500 and 150-500 zooms f/6.3 at the long end. That smaller aperture does help bring the size, and consequently cost down too. Then throw in the usual build quality considerations.


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## kubelik (Feb 15, 2011)

lol said:


> I'll be really interested to see what the electro-optical component does! Just hope is it more affordable and useful than diffractive optics proved to be in practice.



I'm actually more than a little wary of having all that gadgetry in the lens; it just seems like something that has a higher chance of failing mechanically. my doubts may be totally unfounded (after all, there are already quite a number of mechanical and electrical moving parts in lenses these days) but it just sounds like the lens might not hold up to the same rigorous knocking-about that other lenses can withstand. I wouldn't mind being told I'm wrong by some of the engineers here on the forums



lol said:


> Sigma uses a trick of making their 50-500 and 150-500 zooms f/6.3 at the long end. That smaller aperture does help bring the size, and consequently cost down too. Then throw in the usual build quality considerations.



that's a good point. in thinking about it, I decided to look at it from the standpoint of weight reductions in current lenses as a point of comparison. I started with a prime focal length and then looked at the weight ratio when measured against an equal max focal length lens with reduced max aperture. I believe Bob Howland noted elsewhere on the forum that it is the longest focal length that typically defines a lens's size and weight characteristics, so there are times I use zooms due to a lack of compatible prime lens to compare against.

200 f/2 IS (~2500g) -> 70-200 f/2.8 L IS II (~1500g)
1 stop - 40% reduction in weight

300 f/2.8 L IS II (~2350g) -> 300 f/4 L IS (~1200g)
1 stop - 49% reduction in weight

400 f/2.8 L IS II (~3850g) -> 100-400 f/4.5-5.6 L IS (~1400g)
2 stop - 63% reduction in weight

based on these, it looks like each time we come down one stop we are seeing approximately a 45% reduction in weight. so for a 500mm f/5.6 L IS, we could look at the 500 f/4 and extrapolate:

500 f/4 L IS II: 3190g
45% reduction: 1435g
*500 f/5.6 L IS: 1755g*

again, this is very ballpark guesstimation, but I think I have just cause to believe it could be done at least in the sub-2 kilo range


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## Admin US West (Feb 15, 2011)

I respect your thoughts, I was looking at reliability in just the opposite way. 

A pizoelectric crystal is extremely reliable, and if the moving lens group in the IS were eliminated, the reliability might be greatly increased. One of the big hits lenses took in reliability was with the introduction of the moving IS elements. This is not to say that they are horribly unreliable, but they are a weak link.

I really do not expect to see a lens that uses the principle soon, but it would be interesting to see what actually happens to reliability. We do not have enough information about the actual construction to do a accurate analysis, and early implementations will likely be improved on later.


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## /dev/null (Feb 15, 2011)

scalesusa said:


> A pizoelectric crystal is extremely reliable, and if the moving lens group in the IS were eliminated, the reliability might be greatly increased. One of the big hits lenses took in reliability was with the introduction of the moving IS elements. This is not to say that they are horribly unreliable, but they are a weak link.



Fully agree. Each moving element less can only mean better shock resistance and less wear and tear.



> I really do not expect to see a lens that uses the principle soon, but it would be interesting to see what actually happens to reliability. We do not have enough information about the actual construction to do a accurate analysis, and early implementations will likely be improved on later.



We are still waiting for significant improvements of the DO principle. There are some patents out there, but no products...


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## Admin US West (Feb 16, 2011)

Canon still includes examples with pellicle mirrors in some of their patents, and they haven't released one for many years. Many patents are filed to protect a technology and prevent someone doing something clever with it.

Companies are often blind to inventors ideas, the company I worked for turned down a patent by a employee that covered a method to deal with the Y2K situation. They signed over the rights to him, and he had it patented. When it became a very popular solution, he popped up with his patent and cleaned up.


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## GMCPhotographics (Feb 16, 2011)

kubelik said:


> dilbert said:
> 
> 
> > kubelik said:
> ...



The front element alone would make this a hugh ticket, high weight item. The current 400mm f5.6 can get away with a 77mm front filter. A 500mm f5.6 would need a front element of around 90mm....which is quite close to the size of front element in a 300mm f2.8. So it'll be in that kind of price / weigth bracket.


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