Patent: A Pellicle Mirror by Canon
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For those of you who think that mirrorless cameras are the future and Canon does not know what it's doing, think again.
Look at CIPA worldwide camera shipment numbers from http://www.cipa.jp/english/data/dizital.html
a) In 2012, for every unit of MILC shipped, 4.1 units of DSLR are shipped.
From Jan-Aug 2013, for every unit MILC shipped, 4.9 units of DSLR are shipped.
b) When the numbers (shipment ratio of DSLR:MILC) are analyzed on a regional level:
Japan 1.25 (2012), 1.8 (till Aug 2013)
Americas 6.75 (2012), 9.9 (till Aug 2013)
Europe 5.5 (2012), 9.6 (till Aug 2013)
Asia 3.44 (2012), 3.37 (till Aug 2013)
The rest 2.3 (2012), 3.8 (till Aug 2013)
Appears that sales of MILCs are losing steam quite rapidly in America and Europe. Even within Japan, there is a loss of interest in MILCs!
Clearly, the masses are not buying into this silly EVF thing. My one year of experience with OMD taught me the same thing.
Hence, I think a pellicle mirror with electronically adjusted reflectivity/transmittivity is excellent! Combined that with on-sensor PDAF and we have a possible winner. My only concern is whether viewfinder blackout still occurs with this electronic adjustment of pellicle mirror reflectivity. In principle, it should be possible to switch this reflectivity quickly enough to minimize viewfinder blackout.
Look at CIPA worldwide camera shipment numbers from http://www.cipa.jp/english/data/dizital.html
a) In 2012, for every unit of MILC shipped, 4.1 units of DSLR are shipped.
From Jan-Aug 2013, for every unit MILC shipped, 4.9 units of DSLR are shipped.
b) When the numbers (shipment ratio of DSLR:MILC) are analyzed on a regional level:
Japan 1.25 (2012), 1.8 (till Aug 2013)
Americas 6.75 (2012), 9.9 (till Aug 2013)
Europe 5.5 (2012), 9.6 (till Aug 2013)
Asia 3.44 (2012), 3.37 (till Aug 2013)
The rest 2.3 (2012), 3.8 (till Aug 2013)
Appears that sales of MILCs are losing steam quite rapidly in America and Europe. Even within Japan, there is a loss of interest in MILCs!
Clearly, the masses are not buying into this silly EVF thing. My one year of experience with OMD taught me the same thing.
Hence, I think a pellicle mirror with electronically adjusted reflectivity/transmittivity is excellent! Combined that with on-sensor PDAF and we have a possible winner. My only concern is whether viewfinder blackout still occurs with this electronic adjustment of pellicle mirror reflectivity. In principle, it should be possible to switch this reflectivity quickly enough to minimize viewfinder blackout.
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Please explain to me how adding a partially reflective surface into the optical path, and at an angle to boot, is going to improve image quality?
This is a bad idea. Period.
And to those of you saying how bad mirrorless is because sales suck compared to DSLR, just remember a few short years ago when people were saying that digital would never be replace film.....
Time marches on..... but how much progress have we seen in shutters and mirrors? My first SLR, an Olympus OM-1, bought used in 1975, has pretty much the same shutter as a 1DX.... yes, the shutter speed is faster and we now have "silent shutters" but it really has not changed in those 38 years...
Mirrorless offers the potential for no shutters.... and no mirrors (duh!)... a truly electronic camera... no separate focus sensors that need calibration (AFMA vanishes and the nightmare ends), a view that adjusts to conditions, zooms in to check on manual focus, and is customizable to what each user wants..... flexibility that an optical system can never have.... Are they there yet? No! But they are getting closer and how long will it be until EVF is superior to optical....
You should look a bit outside of the DSLR world to see what else is happening, particularly in low light... The latest version of night-vision goggles are staggering! Aerial surveillance platforms where you can auto-track a person walking on a dark street at night from 20,000+ feet from a plane bouncing around so much that half the crew got airsick.... I have a p/s camera that recognizes people and can auto-tag names to faces.... and in "cat mode" will take pictures of a cat, yet will not trigger on a dog ( and the opposite for dog-mode).... these are not trivial tasks.... that p/s camera has about 100 times the computing power of a 5D. That p/s camera is vastly superior to the NASA computing center that sent Apollo to the moon!
My money is on mirrorless.....
This is a bad idea. Period.
And to those of you saying how bad mirrorless is because sales suck compared to DSLR, just remember a few short years ago when people were saying that digital would never be replace film.....
Time marches on..... but how much progress have we seen in shutters and mirrors? My first SLR, an Olympus OM-1, bought used in 1975, has pretty much the same shutter as a 1DX.... yes, the shutter speed is faster and we now have "silent shutters" but it really has not changed in those 38 years...
Mirrorless offers the potential for no shutters.... and no mirrors (duh!)... a truly electronic camera... no separate focus sensors that need calibration (AFMA vanishes and the nightmare ends), a view that adjusts to conditions, zooms in to check on manual focus, and is customizable to what each user wants..... flexibility that an optical system can never have.... Are they there yet? No! But they are getting closer and how long will it be until EVF is superior to optical....
You should look a bit outside of the DSLR world to see what else is happening, particularly in low light... The latest version of night-vision goggles are staggering! Aerial surveillance platforms where you can auto-track a person walking on a dark street at night from 20,000+ feet from a plane bouncing around so much that half the crew got airsick.... I have a p/s camera that recognizes people and can auto-tag names to faces.... and in "cat mode" will take pictures of a cat, yet will not trigger on a dog ( and the opposite for dog-mode).... these are not trivial tasks.... that p/s camera has about 100 times the computing power of a 5D. That p/s camera is vastly superior to the NASA computing center that sent Apollo to the moon!
My money is on mirrorless.....
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Canon had another patent a couple of years ago that made a mirror film that was thinner and not subject to ghosting.
The patent is the result of research done 3-4 years ago, some seem to think it was done yesterday. It takes years for research to turn into a patent.
The dual pixel tech has worked out pretty well, if Canon can improve the next generation of it, maybe the mirror will go away. However, the lenses won't get any smaller, and there is still the EVF that many do not like. EVF's are improving, but are still far from ideal, particularly with moving subjects.
Then, as noted, MILC are fading out. Nikon says it overestimated the market and will concentrate on DSLR's, while Canon is still wanting a breakthrough technology before committing hundreds of millions of dollars.
Sony seems to drop camera lines after 2-3 years to try something new. I'm not sure this inspires confidence in their long term viability.
The patent is the result of research done 3-4 years ago, some seem to think it was done yesterday. It takes years for research to turn into a patent.
The dual pixel tech has worked out pretty well, if Canon can improve the next generation of it, maybe the mirror will go away. However, the lenses won't get any smaller, and there is still the EVF that many do not like. EVF's are improving, but are still far from ideal, particularly with moving subjects.
Then, as noted, MILC are fading out. Nikon says it overestimated the market and will concentrate on DSLR's, while Canon is still wanting a breakthrough technology before committing hundreds of millions of dollars.
Sony seems to drop camera lines after 2-3 years to try something new. I'm not sure this inspires confidence in their long term viability.
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Don Haines said:
I am not aware of anyone saying digital would never replace film. If there were, those folks definitely belonged to the 0.001% minority. In fact, the day digital cameras appeared in the market, many folks already knew film was dead.
The landscape of interchangeable lens cameras will certainly change. But no one knows what the future is going to bring. Current MILC technology is certainly not good enough. The masses have spoken with their wallets and that is louder and far more convincing than anything you and I have to say on the web.
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Now I think I see all this coming together.
A translucent mirror on its own makes something like the sony dslr possible, but they don't have OVF.
In the "classic" canon dslr there is the secondary mirror reflecting light down towards the AF-sensor, so just a translucent mirror would not be possible in connecting with the current AF-systems. (The secondary mirror would be in the lightpath towards the sensor)
But in connection with the new dual-pixel AF it all makes sense!
The variable translucent mirror provides light for the OVF and Sensor ( with its ability for good phase-detection AF).
An can when necessary provide more or less light for one of them by cutting the light towards the other.
Outdoor sports cenario: 50% OVF 50% Sensor 1 stop light loos for Sensor but that us not a problem with good light (or today's ISO ability )
Super fast frame rate ( not limited by the mirror system) and no viewfinder darkening at all.
Low light cenario: for the capture the mirror directs all light towards the sensor or for a short time for better AF or towards the OVF for MF
A translucent mirror on its own makes something like the sony dslr possible, but they don't have OVF.
In the "classic" canon dslr there is the secondary mirror reflecting light down towards the AF-sensor, so just a translucent mirror would not be possible in connecting with the current AF-systems. (The secondary mirror would be in the lightpath towards the sensor)
But in connection with the new dual-pixel AF it all makes sense!
The variable translucent mirror provides light for the OVF and Sensor ( with its ability for good phase-detection AF).
An can when necessary provide more or less light for one of them by cutting the light towards the other.
Outdoor sports cenario: 50% OVF 50% Sensor 1 stop light loos for Sensor but that us not a problem with good light (or today's ISO ability )
Super fast frame rate ( not limited by the mirror system) and no viewfinder darkening at all.
Low light cenario: for the capture the mirror directs all light towards the sensor or for a short time for better AF or towards the OVF for MF
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This is a compromise to reduce size, it probably will reduce image quality a bit though not much. However, the target market for smaller cameras generally does not have paramount quality as the #1 concern, size is the #1 concern for said market. The advantage is that it could use existing EF-S lenses, so this could be a replacement to the Rebel SL1 for instance.
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A few years ago, buyers were flocking to digital and sales proved it. Its true, some entrenched individuals at Kodak did not believe it would happen, they refused to believe in the sales figures. They put their money on film.Don Haines said:
Check the sales figures, its a fact, mirrorless sales have tanked! Once buyers find that they have the same large lens and the little bitty camera with lousy EVF, they go for a DSLR.
That does not mean they are bad cameras, just that they are not ready to take over the market from DSLR's , and the hype turns out to be over stated.
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P
pharp
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I think there is a common misconception that the only reason for making a MILC is to decrease the size - WRONG! As noted by others, there are many good reasons for ditching the mirror/pentaprism - inevitable IMHO. The problem to date, as I see it, there just haven't been any really compelling 'system' cameras available. If canon made a mirrorless 6D - size, etc being the same with a really good EVF - I think it would sell in droves. I'd buy one tommorrow.
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Have been surveying the machine translation of JP2013-218241 from Japanese into English as provided by JPO a bit...
In terms of prior art JP2013-218241 initially references JP2002-182268 which deals with a DSLR having a 45deg fixed half mirror. This patent does not deal with the half mirror as such but with the fact that a fixed half mirror does not exhibit a “mirror slab” and combined with a low noise shutter the photo taking can be made less intrusive. JP2013-218241 however uses said patent as an example of the inherent light sharing compromise between the OVF and the image sensor and states that a “modulated” mirror is a solution for this problem. As for an example of a modulated mirror JP2013-218241A refers to JP2007-102197 aka US75541551 which deals with electrochromic thin film/multilayer constructs, aimed at controlling heat transfer trough windows in houses and vehicles - in other words sun filters. By applying voltages of different polarity to the appropriate layers, the optical properties of the construct can be changed between a state with transmittance/reflectance of 0%/27% and another state with 48%/6% respectively - with one caveat though, the switch from low to high transmissivity takes about 40secs @ λ = 670nm (red/NIR) and the other from high to low transmissivity about 15secs.
JP2013-218241 in its embodiment goes on to state that since light measurement is made on the OVF path and to ensure adequate OVF brightness at low light levels the reflection towards the finder should not be less than 60% (40% left for phase detection on the image sensor). An interesting aspect of the patent app is that the modulated mirror not only removes the mirror slab but also replaces the shutter – thus constituting a virtually noise free DSLR. The patent mentions both a still and an “animated” mode with up to 15 frames/sec.
For those interested there is also the Canon patent app US20130002925 which also deals with a modulated mirror, or in this case referred to as “variable translucency” mirror. The technology used to achieve any level of translucency/reflectance between 100%/0% and 0%/100% respectively is based on so called “Micro blinds”, aimed at windows and automotive use as detailed in US7684105.
Surely, - only Canon knows what is going on in their “skunkworks”, but I see some substantial challenges for this type of modulated mirror technology that need to be overcome before a camera using this principle will materialize. For JP2013-218241 would include optical state switching speed, transmissivity, durability (i.e. lifetime), environmental sensitivity, and color casts and for US20130002925 the most obvious ones would include durability (i.e. lifetime), diffraction (even though this is considered US7684105), light incident angles when applied to a 45 deg mirror.
I personally would therfore not bet on seeing a camera based on either of these patents anytime soon, and view this mostly as a “possibly applications of technologies not initially intended for use in cameras and hence preventing others from doing it first” type of patent apps..
But as we all know however, prediction is a skilled art, especially when it comes to the future..
In terms of prior art JP2013-218241 initially references JP2002-182268 which deals with a DSLR having a 45deg fixed half mirror. This patent does not deal with the half mirror as such but with the fact that a fixed half mirror does not exhibit a “mirror slab” and combined with a low noise shutter the photo taking can be made less intrusive. JP2013-218241 however uses said patent as an example of the inherent light sharing compromise between the OVF and the image sensor and states that a “modulated” mirror is a solution for this problem. As for an example of a modulated mirror JP2013-218241A refers to JP2007-102197 aka US75541551 which deals with electrochromic thin film/multilayer constructs, aimed at controlling heat transfer trough windows in houses and vehicles - in other words sun filters. By applying voltages of different polarity to the appropriate layers, the optical properties of the construct can be changed between a state with transmittance/reflectance of 0%/27% and another state with 48%/6% respectively - with one caveat though, the switch from low to high transmissivity takes about 40secs @ λ = 670nm (red/NIR) and the other from high to low transmissivity about 15secs.
JP2013-218241 in its embodiment goes on to state that since light measurement is made on the OVF path and to ensure adequate OVF brightness at low light levels the reflection towards the finder should not be less than 60% (40% left for phase detection on the image sensor). An interesting aspect of the patent app is that the modulated mirror not only removes the mirror slab but also replaces the shutter – thus constituting a virtually noise free DSLR. The patent mentions both a still and an “animated” mode with up to 15 frames/sec.
For those interested there is also the Canon patent app US20130002925 which also deals with a modulated mirror, or in this case referred to as “variable translucency” mirror. The technology used to achieve any level of translucency/reflectance between 100%/0% and 0%/100% respectively is based on so called “Micro blinds”, aimed at windows and automotive use as detailed in US7684105.
Surely, - only Canon knows what is going on in their “skunkworks”, but I see some substantial challenges for this type of modulated mirror technology that need to be overcome before a camera using this principle will materialize. For JP2013-218241 would include optical state switching speed, transmissivity, durability (i.e. lifetime), environmental sensitivity, and color casts and for US20130002925 the most obvious ones would include durability (i.e. lifetime), diffraction (even though this is considered US7684105), light incident angles when applied to a 45 deg mirror.
I personally would therfore not bet on seeing a camera based on either of these patents anytime soon, and view this mostly as a “possibly applications of technologies not initially intended for use in cameras and hence preventing others from doing it first” type of patent apps..
But as we all know however, prediction is a skilled art, especially when it comes to the future..
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MILC sales numbers are low due to one reason only: rather unattractive MILCS so far. EOS-M ... Nikon 1 ... or mFT.
As soon as really good MILCs are availbale, DSLR sales will fall, MILC sales will rise. As simple as that.
Sony A7/R are the turning point, even if their sales should turn out to be disappointing. Why? Because it has been proven, that cameras with large and good sensors don't need to be large, clunky and heavy.
As afra as lenses are concerned: probably 90% of all images are captured at focal lengths that can be build into small and light lenses. Only a small minority of photographers really NEED to use longer focal length lenses that will be large and heavy as long as glass-based optics are not replaced by something better.
As far as the "variable transmission tech" is concerned: I would prefer Canon to look into this NOT for pellicle mirrors but for fully electronic shutters and possibly also for fully electronic lens apertures, perfgeclty round at any opening - instead of mechanical iris / blades.
I'd love to finally get a 100% digital, electronic camera, devoid of any pre-historic mechanical ballast from the phtographic stone-age. No mirror slap. No shutter-cracking, no shutter-cocking/re-winding. No vibrations. No noise. That is my idea of "pure photography" [ (c) Nikon ;-)] ... in "pure silence".
Imaging with light. Arranging incoming photons. Rather than wielding mechanical and chemical contraptions. Luckily we got rid of the chemical stuff. Now it's time to unload the mechanical stuff too.
As soon as really good MILCs are availbale, DSLR sales will fall, MILC sales will rise. As simple as that.
Sony A7/R are the turning point, even if their sales should turn out to be disappointing. Why? Because it has been proven, that cameras with large and good sensors don't need to be large, clunky and heavy.
As afra as lenses are concerned: probably 90% of all images are captured at focal lengths that can be build into small and light lenses. Only a small minority of photographers really NEED to use longer focal length lenses that will be large and heavy as long as glass-based optics are not replaced by something better.
As far as the "variable transmission tech" is concerned: I would prefer Canon to look into this NOT for pellicle mirrors but for fully electronic shutters and possibly also for fully electronic lens apertures, perfgeclty round at any opening - instead of mechanical iris / blades.
I'd love to finally get a 100% digital, electronic camera, devoid of any pre-historic mechanical ballast from the phtographic stone-age. No mirror slap. No shutter-cracking, no shutter-cocking/re-winding. No vibrations. No noise. That is my idea of "pure photography" [ (c) Nikon ;-)] ... in "pure silence".
Imaging with light. Arranging incoming photons. Rather than wielding mechanical and chemical contraptions. Luckily we got rid of the chemical stuff. Now it's time to unload the mechanical stuff too.
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Don Haines said:
AFAIK, there's no reason you couldn't do a shutterless traditional DSLR. Honestly, I'm surprised DSLRs even still have a shutter. It's a vestigial organ that can be made completely unnecessary by proper buffering (which is also the way you fix the rolling shutter problem in video mode).
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Don Haines said:
Um.. Technology Improvement?
Partially reflective surface: When light hits an object part of it is reflected, transmitted, and absorb by the object. You ask how adding an object into optical path improve image quality, isn't it longer lens got more elements on it than a prime lens, but we never question its optical transmission quality.
Similarly with this scenario, adding an high light transmittivity material wont affect image quality much. if we can possible vary the reflectivity/transmittivity of material in a high quality, then i dont see any problem.
I hope I got a point. But cheers.
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Done right it could be a perfectly good idea where the gains far, far outweigh the loss of a little bit of light. Even the Sony SLTs weren't that bad imo.
Some people go anal over 1/3 stop of light. OK I obviously understand the significance of light in general, but if a camera this mirror thing improved ISO to compensate, I'd gladly take the very high FPS, no "mirror blackout" and if armed with a (very fast and hi-res) EVF it'd also have a live view of the exposure.
And all the above will improve, because technology always does ...
As for that bit of light loss, different lenses, different brands already can vary by 1/3 stop if not more of light anyway in their native designs. So you better check all your lenses if you're that paranoid losing light
(cue usual elitist posts on how such "features" are a crutch and not real photography)
Some people go anal over 1/3 stop of light. OK I obviously understand the significance of light in general, but if a camera this mirror thing improved ISO to compensate, I'd gladly take the very high FPS, no "mirror blackout" and if armed with a (very fast and hi-res) EVF it'd also have a live view of the exposure.
And all the above will improve, because technology always does ...
As for that bit of light loss, different lenses, different brands already can vary by 1/3 stop if not more of light anyway in their native designs. So you better check all your lenses if you're that paranoid losing light
(cue usual elitist posts on how such "features" are a crutch and not real photography)
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dufflover said:
No. Pellicle-mirrored = does nothing, a mirrorless camera will not do much better.
Mirrorless actually combines EVF (considered as a disadvantage by many DSLR users) and all the bulk of a DSLR. Plus light loss and possible degradation of IQ due to reflections on top. That's one of the reasons, why Sony is quitting their SLT line of cameras. Dead end!
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privatebydesign said:
Totally agree. Some kind of piezoelectric pellicle mirror would certainly tickle my fancy! I'd pick up one of those, for almost any cost, before even looking at a mirrorless with an EVF. I wonder if it is possible, though...to use some kind of electrostatically activated mirror that doesn't result in any light loss when deactivated for exposure...
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Don Haines said:
Regarding the emphasized part above...I would say never. I think an EVF could get very close to being "as good as" an OVF, but an optical viewfinder is ultimately only going to be limited by the viewers eyes. There is going to be no limit on dynamic range, only the lens will limit resolving power, it will always work in any light level (i.e. I use my OVF to find stars when doing astrophotography...stars, which have about 0.0020-0.0025 lux), and always updates instantaneously when your scene changes. No matter how you slice it...an EVF will never be "superior" to those things.
Given that an EVF is ultimately dependent upon the sensor for low-light sensitivity, barring some unbelievably radical change in how low light sensitivity is achieved, I don't foresee an EVF ever supporting astrophotography...even with 100% Q.E., more than half the stars in the night sky that are visible with an OVF are going to be lost to noise with an EVF. Dynamic range will never be infinite with an EVF, as the sensor's DR will never be infinite. For an EVF's pixels to be invisible to an eye with 20/20 vision, they would need to be so small that they would filter out a moderate amount of red light, and to be invisible to an eye with 20/10 vision, they would need pixels so small that they would filter out most red light.
I'll probably have no choice, at some point in the future, but to switch to mirrorless. When that day comes, I'll do it as begrudgingly as a human being can begrudge...as from a technical standpoint I do not see how an EVF will ever even be as good as an OVF, let alone superior to one. Personally, I am hoping the classic slap-happy, noisy DSLR lasts for another 50 years...after which point I'll probably be dead, and will no longer care.
;D
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