Selective Light Conducting Material
-
I hope I can explain what I am looking for, as should you (hope that is.) I need a piece of transparent material that can be gradually made opaque but not as a whole, rather individual segments of the material. So I can say upper left corner go 50% opaque, a circular middle section go 75% and the rest be transparent. It involves obviously some controller unit to tell the material where to opaque and where to remain transparent. The segments need to be quite small as well, able to define fine graded edges and not be visible to the naked eye up close. Is there such a material? I was thinking something like what LCD screens are made of, but I have no idea wether those let light through or that they consist of billions of light emitting segments, which is not what I would need. Also the least amount of light loss through the transparent sections the better. i.e. 100% transparent. Though this is not critical. I know there are plenty of engineers on CP so I reckon someone must have an idea of what I am looking for. Thanks chaps :)
Paul Watson
Bluegrass
Cape Town, South AfricaMacbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Shog9: Paul "The human happy pill" Watson
-
I hope I can explain what I am looking for, as should you (hope that is.) I need a piece of transparent material that can be gradually made opaque but not as a whole, rather individual segments of the material. So I can say upper left corner go 50% opaque, a circular middle section go 75% and the rest be transparent. It involves obviously some controller unit to tell the material where to opaque and where to remain transparent. The segments need to be quite small as well, able to define fine graded edges and not be visible to the naked eye up close. Is there such a material? I was thinking something like what LCD screens are made of, but I have no idea wether those let light through or that they consist of billions of light emitting segments, which is not what I would need. Also the least amount of light loss through the transparent sections the better. i.e. 100% transparent. Though this is not critical. I know there are plenty of engineers on CP so I reckon someone must have an idea of what I am looking for. Thanks chaps :)
Paul Watson
Bluegrass
Cape Town, South AfricaMacbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Shog9: Paul "The human happy pill" Watson
Sounds awfully complicated. Why do you need this? Perhaps there is some other way of achieving the same results? J
"You can get anything you want at Alice's Restaurant."
-
I hope I can explain what I am looking for, as should you (hope that is.) I need a piece of transparent material that can be gradually made opaque but not as a whole, rather individual segments of the material. So I can say upper left corner go 50% opaque, a circular middle section go 75% and the rest be transparent. It involves obviously some controller unit to tell the material where to opaque and where to remain transparent. The segments need to be quite small as well, able to define fine graded edges and not be visible to the naked eye up close. Is there such a material? I was thinking something like what LCD screens are made of, but I have no idea wether those let light through or that they consist of billions of light emitting segments, which is not what I would need. Also the least amount of light loss through the transparent sections the better. i.e. 100% transparent. Though this is not critical. I know there are plenty of engineers on CP so I reckon someone must have an idea of what I am looking for. Thanks chaps :)
Paul Watson
Bluegrass
Cape Town, South AfricaMacbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Shog9: Paul "The human happy pill" Watson
LCDs are exactly what you are looking for. An LCD is a long molecule which is sufficiently polar to be aligned by an electric field. Suspended between plates on which electrodes have been deposited they can be addressed by segment. When the molecules are in an unaligned state their positions are unordered, and they transmit light between the plates. When they are aligned by the application of a voltage, the regions so aligned become oriented like a polarizing filter, and can be used to block or reflect light depending on the configuration. A transmissivity of 100% is not acheivable, but with properly polarized plates and strong backlighting you can do well enough. Would I be correct in assuming that you have a photographic accessory in mind?:) Real-time electronic cropping and vignetting, perhaps? "Please don't put cigarette butts in the urinal. It makes them soggy and hard to light" - Sign in a Bullhead City, AZ Restroom
-
I hope I can explain what I am looking for, as should you (hope that is.) I need a piece of transparent material that can be gradually made opaque but not as a whole, rather individual segments of the material. So I can say upper left corner go 50% opaque, a circular middle section go 75% and the rest be transparent. It involves obviously some controller unit to tell the material where to opaque and where to remain transparent. The segments need to be quite small as well, able to define fine graded edges and not be visible to the naked eye up close. Is there such a material? I was thinking something like what LCD screens are made of, but I have no idea wether those let light through or that they consist of billions of light emitting segments, which is not what I would need. Also the least amount of light loss through the transparent sections the better. i.e. 100% transparent. Though this is not critical. I know there are plenty of engineers on CP so I reckon someone must have an idea of what I am looking for. Thanks chaps :)
Paul Watson
Bluegrass
Cape Town, South AfricaMacbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Shog9: Paul "The human happy pill" Watson
Yes, they let light through. Think overhead projectors. For example: http://www.v-lyte.com/benefits_tr.htmhttp://www.v-lyte.com/benefits_tr.htm[^] Here's a web site with cute pictures on how front light vs. back lighted LCD's work: http://www.minebea-ele.com/en/product/lighting/E_1000/E_1001.html[^] Now, I don't think anybody has done this as a camera lense adapter. Sure would be interesting. What about two or more polizared pieces of glass rotated at various angles to control the light density? Though I haven't heard of anyone doing this for regions of the field of view. Marc Help! I'm an AI running around in someone's f*cked up universe simulator.
Sensitivity and ethnic diversity means celebrating difference, not hiding from it. - Christian Graus
Every line of code is a liability - Taka Muraoka
Microsoft deliberately adds arbitrary layers of complexity to make it difficult to deliver Windows features on non-Windows platforms--Microsoft's "Halloween files" -
Sounds awfully complicated. Why do you need this? Perhaps there is some other way of achieving the same results? J
"You can get anything you want at Alice's Restaurant."
Jamie Hale wrote: Why do you need this? Perhaps there is some other way of achieving the same results? There very well maybe, but I have racked my brain and cannot think of it. Ok it is for photography, you all guessed that already, and basically what I want to do is create an active neural density filter. Photographers strap these filters onto the front of their lenses which have a graded density glass. So at the top of the glass it would be 50% opaque and then it would slowly fade towards halfway until it was transparent and the other half of the glass would be totally transparent. The idea is that there are scenes which are too contrasty to capture on film without either blowing out the bright area or silohuetting the dark area. e.g. a sunset. So they then place the filter so that the sunlit sky part is behind the opaque area and the foreground which is not as bright is behind the transparent area. That way you get a less contrasty scene falling onto the film. All very nifty. The thing is that only works well for horizons and straight edged scenes where you can easily lay the transition line of the graded glass along the horizon. What happens if you have a lighthouse sticking up in the middle? Then the top of your lighthouse is underexposed as it is covered by the opaque glass and the bottom is fine, which is not good. You would want the filter to basically do a magic wand around the lighthouse, going totally transparent for it but not for the sky behind it. So my idea is simple enough; Have this "active" filter on the end of your glass connected to a tablet PC or laptop. On the laptop would be the image feed from the digital camera and then with a pen you could trace out the areas you want and assign transparency values to them. That then goes back to the filter material and darkens or lightens the sections you have defined. Simple idea, probably a bitch to implement. I can't think of anything but (just got an email from Roger now) something like a LCD being able to do the trick. Physical slides would be hard to control and how do you make them selectively opaque?
Paul Watson
Bluegrass
Cape Town, South AfricaMacbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returnin
-
I hope I can explain what I am looking for, as should you (hope that is.) I need a piece of transparent material that can be gradually made opaque but not as a whole, rather individual segments of the material. So I can say upper left corner go 50% opaque, a circular middle section go 75% and the rest be transparent. It involves obviously some controller unit to tell the material where to opaque and where to remain transparent. The segments need to be quite small as well, able to define fine graded edges and not be visible to the naked eye up close. Is there such a material? I was thinking something like what LCD screens are made of, but I have no idea wether those let light through or that they consist of billions of light emitting segments, which is not what I would need. Also the least amount of light loss through the transparent sections the better. i.e. 100% transparent. Though this is not critical. I know there are plenty of engineers on CP so I reckon someone must have an idea of what I am looking for. Thanks chaps :)
Paul Watson
Bluegrass
Cape Town, South AfricaMacbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Shog9: Paul "The human happy pill" Watson
BTW, by using such a device on an "anolog", or film camera, you are essentially turning it into a digital camera by the nature of the LCD--specific point sources. Therefore, you're better off doing this natively with a digital camera. I think I've seen this kind of adaptive light metering on some of the fancy digital cameras. Marc Help! I'm an AI running around in someone's f*cked up universe simulator.
Sensitivity and ethnic diversity means celebrating difference, not hiding from it. - Christian Graus
Every line of code is a liability - Taka Muraoka
Microsoft deliberately adds arbitrary layers of complexity to make it difficult to deliver Windows features on non-Windows platforms--Microsoft's "Halloween files" -
Jamie Hale wrote: Why do you need this? Perhaps there is some other way of achieving the same results? There very well maybe, but I have racked my brain and cannot think of it. Ok it is for photography, you all guessed that already, and basically what I want to do is create an active neural density filter. Photographers strap these filters onto the front of their lenses which have a graded density glass. So at the top of the glass it would be 50% opaque and then it would slowly fade towards halfway until it was transparent and the other half of the glass would be totally transparent. The idea is that there are scenes which are too contrasty to capture on film without either blowing out the bright area or silohuetting the dark area. e.g. a sunset. So they then place the filter so that the sunlit sky part is behind the opaque area and the foreground which is not as bright is behind the transparent area. That way you get a less contrasty scene falling onto the film. All very nifty. The thing is that only works well for horizons and straight edged scenes where you can easily lay the transition line of the graded glass along the horizon. What happens if you have a lighthouse sticking up in the middle? Then the top of your lighthouse is underexposed as it is covered by the opaque glass and the bottom is fine, which is not good. You would want the filter to basically do a magic wand around the lighthouse, going totally transparent for it but not for the sky behind it. So my idea is simple enough; Have this "active" filter on the end of your glass connected to a tablet PC or laptop. On the laptop would be the image feed from the digital camera and then with a pen you could trace out the areas you want and assign transparency values to them. That then goes back to the filter material and darkens or lightens the sections you have defined. Simple idea, probably a bitch to implement. I can't think of anything but (just got an email from Roger now) something like a LCD being able to do the trick. Physical slides would be hard to control and how do you make them selectively opaque?
Paul Watson
Bluegrass
Cape Town, South AfricaMacbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returnin
I figured it was something like that. Paul, you have to start developing your own film. :) You have all kinds of control when you're the one exposing the photo paper. I did a bit of fiddling with stuff like that back in university. Dodging and burning - just like Photoshop. Of course if you want fancy tech-toys, I have no solutions for you. :)
-
BTW, by using such a device on an "anolog", or film camera, you are essentially turning it into a digital camera by the nature of the LCD--specific point sources. Therefore, you're better off doing this natively with a digital camera. I think I've seen this kind of adaptive light metering on some of the fancy digital cameras. Marc Help! I'm an AI running around in someone's f*cked up universe simulator.
Sensitivity and ethnic diversity means celebrating difference, not hiding from it. - Christian Graus
Every line of code is a liability - Taka Muraoka
Microsoft deliberately adds arbitrary layers of complexity to make it difficult to deliver Windows features on non-Windows platforms--Microsoft's "Halloween files"Marc Clifton wrote: you are essentially turning it into a digital camera by the nature of the LCD Shit not what I want then. Are you saying the LCD "segments" basically "pixelise" the light coming through? Actually I don't get what you mean? Marc Clifton wrote: I think I've seen this kind of adaptive light metering on some of the fancy digital cameras. None of even the top-end public digital cameras do that. I have seen it though on scientific cameras running into the millions where the receptivity of the pixels in the CCD/CMOS/Whatever can be individually changed, resulting in the same affect. Awesome stuff. Though I still like film, and an "active" ND grad filter would be something quite awesome in a photographers bag of tricks.
Paul Watson
Bluegrass
Cape Town, South AfricaMacbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Shog9: Paul "The human happy pill" Watson
-
I hope I can explain what I am looking for, as should you (hope that is.) I need a piece of transparent material that can be gradually made opaque but not as a whole, rather individual segments of the material. So I can say upper left corner go 50% opaque, a circular middle section go 75% and the rest be transparent. It involves obviously some controller unit to tell the material where to opaque and where to remain transparent. The segments need to be quite small as well, able to define fine graded edges and not be visible to the naked eye up close. Is there such a material? I was thinking something like what LCD screens are made of, but I have no idea wether those let light through or that they consist of billions of light emitting segments, which is not what I would need. Also the least amount of light loss through the transparent sections the better. i.e. 100% transparent. Though this is not critical. I know there are plenty of engineers on CP so I reckon someone must have an idea of what I am looking for. Thanks chaps :)
Paul Watson
Bluegrass
Cape Town, South AfricaMacbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Shog9: Paul "The human happy pill" Watson
It should be possible to get LCD panels that can be selectively darkened. As to light loss, you are looking at a maximum of 50% transmission when it is set to transparent. This is because LCDs work only with polarized light and to polarize ambient light, you have to throw out (i.e., absorb) the 50% with the wrong polarization. LCDs can also show chromatic behavior where the attenuation varies with wavelength. There are materials that can become selectively absorptive or reflective, but these are generally somewhat exotic and quite expensive. One question would be how fast you need to switch. If switching speed is not critical, I would think about something microfluidic, where you would flow liquid dye of different concentrations into different cells in the device. Switching speed would be excrucuatingly slow, but you could get arbitrary transmissions between 0% and 100% with good achromatic behavior and a much better contrast ratio than LCDs could provide. I don’t think nation-building missions are worthwhile. George W. Bush
-
Marc Clifton wrote: you are essentially turning it into a digital camera by the nature of the LCD Shit not what I want then. Are you saying the LCD "segments" basically "pixelise" the light coming through? Actually I don't get what you mean? Marc Clifton wrote: I think I've seen this kind of adaptive light metering on some of the fancy digital cameras. None of even the top-end public digital cameras do that. I have seen it though on scientific cameras running into the millions where the receptivity of the pixels in the CCD/CMOS/Whatever can be individually changed, resulting in the same affect. Awesome stuff. Though I still like film, and an "active" ND grad filter would be something quite awesome in a photographers bag of tricks.
Paul Watson
Bluegrass
Cape Town, South AfricaMacbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Shog9: Paul "The human happy pill" Watson
Paul Watson wrote: Are you saying the LCD "segments" basically "pixelise" the light coming through? Yes. They're made up of tiny transistors. Marc Help! I'm an AI running around in someone's f*cked up universe simulator.
Sensitivity and ethnic diversity means celebrating difference, not hiding from it. - Christian Graus
Every line of code is a liability - Taka Muraoka
Microsoft deliberately adds arbitrary layers of complexity to make it difficult to deliver Windows features on non-Windows platforms--Microsoft's "Halloween files" -
I figured it was something like that. Paul, you have to start developing your own film. :) You have all kinds of control when you're the one exposing the photo paper. I did a bit of fiddling with stuff like that back in university. Dodging and burning - just like Photoshop. Of course if you want fancy tech-toys, I have no solutions for you. :)
Anonymous wrote: I figured it was something like that. I am very transparent *groan* Anonymous wrote: Paul, you have to start developing your own film. You have all kinds of control when you're the one exposing the photo paper. I did a bit of fiddling with stuff like that back in university. Dodging and burning - just like Photoshop. I know, I know. That will come for sure. I am shooting B&W (Ilford) at the moment. First I want to get a bit more confident with exposure control, then I am going to venture into chemicals and darkroom magic. Photoshop is grand but there are things it cannot do which can be done in the darkroom. I even want to give the Zone system a serious bash, which means my own darkroom. However an "active" ND grad filter would be a kiff thing. Once the film has recorded a scene there is only so much playing you can do; so much dodging, burning etc. Eventually you run into the fact that the film simply did not record any light in that one area, or recorded so much that it blocked up. With a filter like that though you get to make sure the light falling on the film is within those unplayable limits, then you are free in the darkroom to do all sorts with that base information at your fingertips. Anonymous wrote: Of course if you want fancy tech-toys, I have no solutions for you. I think there is an incredible opportunity for a synergy of digital and analog in the photographic world. For instance a simple example; Why the hell are us film photographers still looking through analog viewfinders? It is patently obvious that a digital sensor in front of the film plane (instead of the normal prism) feeding to a LCD on the back of the camera and into the viewfinder would be a fantastic idea. Then you get all the cool tech that comes with a digital sensor, but the quality and wonder of film for the final recording. Expensive at first, but then all of these ideas are expensive at first and then work their way down. There are numerous other areas where film cameras can benefit from digital technology without going anywhere near the film plane. I don't want any digital tech touching my film, but it sure would help getting the right light to fall onto the film :)
Paul Watson
-
Anonymous wrote: I figured it was something like that. I am very transparent *groan* Anonymous wrote: Paul, you have to start developing your own film. You have all kinds of control when you're the one exposing the photo paper. I did a bit of fiddling with stuff like that back in university. Dodging and burning - just like Photoshop. I know, I know. That will come for sure. I am shooting B&W (Ilford) at the moment. First I want to get a bit more confident with exposure control, then I am going to venture into chemicals and darkroom magic. Photoshop is grand but there are things it cannot do which can be done in the darkroom. I even want to give the Zone system a serious bash, which means my own darkroom. However an "active" ND grad filter would be a kiff thing. Once the film has recorded a scene there is only so much playing you can do; so much dodging, burning etc. Eventually you run into the fact that the film simply did not record any light in that one area, or recorded so much that it blocked up. With a filter like that though you get to make sure the light falling on the film is within those unplayable limits, then you are free in the darkroom to do all sorts with that base information at your fingertips. Anonymous wrote: Of course if you want fancy tech-toys, I have no solutions for you. I think there is an incredible opportunity for a synergy of digital and analog in the photographic world. For instance a simple example; Why the hell are us film photographers still looking through analog viewfinders? It is patently obvious that a digital sensor in front of the film plane (instead of the normal prism) feeding to a LCD on the back of the camera and into the viewfinder would be a fantastic idea. Then you get all the cool tech that comes with a digital sensor, but the quality and wonder of film for the final recording. Expensive at first, but then all of these ideas are expensive at first and then work their way down. There are numerous other areas where film cameras can benefit from digital technology without going anywhere near the film plane. I don't want any digital tech touching my film, but it sure would help getting the right light to fall onto the film :)
Paul Watson
Paul Watson wrote: Why the hell are us film photographers still looking through analog viewfinders? Because LCD lies. It hasn't the resolution, it hasn't the luminensce range, and it hasn't the color accuracy. You're eye (which lies to you too) is the most sensitive device. Putting an LCD display between the image and your eye degrades the quality of the image that you are perceiving. The only advantage would be IR illumination for night shots. Marc Help! I'm an AI running around in someone's f*cked up universe simulator.
Sensitivity and ethnic diversity means celebrating difference, not hiding from it. - Christian Graus
Every line of code is a liability - Taka Muraoka
Microsoft deliberately adds arbitrary layers of complexity to make it difficult to deliver Windows features on non-Windows platforms--Microsoft's "Halloween files" -
Jamie Hale wrote: Why do you need this? Perhaps there is some other way of achieving the same results? There very well maybe, but I have racked my brain and cannot think of it. Ok it is for photography, you all guessed that already, and basically what I want to do is create an active neural density filter. Photographers strap these filters onto the front of their lenses which have a graded density glass. So at the top of the glass it would be 50% opaque and then it would slowly fade towards halfway until it was transparent and the other half of the glass would be totally transparent. The idea is that there are scenes which are too contrasty to capture on film without either blowing out the bright area or silohuetting the dark area. e.g. a sunset. So they then place the filter so that the sunlit sky part is behind the opaque area and the foreground which is not as bright is behind the transparent area. That way you get a less contrasty scene falling onto the film. All very nifty. The thing is that only works well for horizons and straight edged scenes where you can easily lay the transition line of the graded glass along the horizon. What happens if you have a lighthouse sticking up in the middle? Then the top of your lighthouse is underexposed as it is covered by the opaque glass and the bottom is fine, which is not good. You would want the filter to basically do a magic wand around the lighthouse, going totally transparent for it but not for the sky behind it. So my idea is simple enough; Have this "active" filter on the end of your glass connected to a tablet PC or laptop. On the laptop would be the image feed from the digital camera and then with a pen you could trace out the areas you want and assign transparency values to them. That then goes back to the filter material and darkens or lightens the sections you have defined. Simple idea, probably a bitch to implement. I can't think of anything but (just got an email from Roger now) something like a LCD being able to do the trick. Physical slides would be hard to control and how do you make them selectively opaque?
Paul Watson
Bluegrass
Cape Town, South AfricaMacbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returnin
Sounds like an idea that I had once for a dynamic sunshade in a car. Build the windshield so that it could position a variably sized opaque circle right over where the bright center of the sun was coming through the window. Track the position of the drivers head so that it would move with them and always be between their face and the sun. Could never figure out a way to do it.
Paul Watson wrote: "At the end of the day it is what you produce that counts, not how many doctorates you have on the wall." George Carlin wrote: "Don't sweat the petty things, and don't pet the sweaty things." Jörgen Sigvardsson wrote: If the physicists find a universal theory describing the laws of universe, I'm sure the asshole constant will be an integral part of that theory.
-
Paul Watson wrote: Why the hell are us film photographers still looking through analog viewfinders? Because LCD lies. It hasn't the resolution, it hasn't the luminensce range, and it hasn't the color accuracy. You're eye (which lies to you too) is the most sensitive device. Putting an LCD display between the image and your eye degrades the quality of the image that you are perceiving. The only advantage would be IR illumination for night shots. Marc Help! I'm an AI running around in someone's f*cked up universe simulator.
Sensitivity and ethnic diversity means celebrating difference, not hiding from it. - Christian Graus
Every line of code is a liability - Taka Muraoka
Microsoft deliberately adds arbitrary layers of complexity to make it difficult to deliver Windows features on non-Windows platforms--Microsoft's "Halloween files"(It says I am anonymous, but no, I am Mighty Mouse! err I mean Paul Watson) Marc Clifton wrote: It hasn't the resolution, it hasn't the luminensce range, and it hasn't the color accuracy No, you are right. I certainly would not want what passes for the screens of current digital cameras as a replacement for my viewfinder. But there must be better technology out there than LCD for small displays, right? I was quite shocked to find out how much light is distorted even through the best SLR camera systems. I was reading SLRs Finding The View on photo.NET and was amazed how there was a trade off between one aspect and the other, both desirable but neither can be had at 100% together. The Canon guy who came around to my camera club the other night showed how the back panel that is on my Canon EOS 300v is a change meant to ween film photographers off film bodies towards digital bodies which have the LCDs on the back. I think it is pretty useful having a LCD on the back of a camera. For one it helps you visualise a shot as to how it will look when printed. Through a viewfinder you can be fooled as to how the shot will actually look with borders. Do forgive me, I am just a rather encourageable and enthusiastic chap. :)
-
I hope I can explain what I am looking for, as should you (hope that is.) I need a piece of transparent material that can be gradually made opaque but not as a whole, rather individual segments of the material. So I can say upper left corner go 50% opaque, a circular middle section go 75% and the rest be transparent. It involves obviously some controller unit to tell the material where to opaque and where to remain transparent. The segments need to be quite small as well, able to define fine graded edges and not be visible to the naked eye up close. Is there such a material? I was thinking something like what LCD screens are made of, but I have no idea wether those let light through or that they consist of billions of light emitting segments, which is not what I would need. Also the least amount of light loss through the transparent sections the better. i.e. 100% transparent. Though this is not critical. I know there are plenty of engineers on CP so I reckon someone must have an idea of what I am looking for. Thanks chaps :)
Paul Watson
Bluegrass
Cape Town, South AfricaMacbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Shog9: Paul "The human happy pill" Watson
I know this isn't what you are looking for, but some specialized video cameras have logrithmic light sensitivity. With then you can do such tricks as viewing the filament of a light bulb and the markings on the light bulb at the same time. You might find a Russian army surplus rig that does this kind of thing.
-
It should be possible to get LCD panels that can be selectively darkened. As to light loss, you are looking at a maximum of 50% transmission when it is set to transparent. This is because LCDs work only with polarized light and to polarize ambient light, you have to throw out (i.e., absorb) the 50% with the wrong polarization. LCDs can also show chromatic behavior where the attenuation varies with wavelength. There are materials that can become selectively absorptive or reflective, but these are generally somewhat exotic and quite expensive. One question would be how fast you need to switch. If switching speed is not critical, I would think about something microfluidic, where you would flow liquid dye of different concentrations into different cells in the device. Switching speed would be excrucuatingly slow, but you could get arbitrary transmissions between 0% and 100% with good achromatic behavior and a much better contrast ratio than LCDs could provide. I don’t think nation-building missions are worthwhile. George W. Bush
Jonathan Gilligan wrote: One question would be how fast you need to switch. If switching speed is not critical, I would think about something microfluidic, where you would flow liquid dye of different concentrations into different cells in the device. Switching speed would be excrucuatingly slow By excrutiatingly slow do you mean seconds, minutes... ...hours? The kind of photographer who uses a ND grad filter generally takes hours to setup a shot. They can definitley make do with a system that takes a few minutes to get into "position." No problem there. Sure maybe 50 years from now a super fast active ND grad filter would be viable for action photography, but in the short term only landscape type photographers would find it really useful. Jonathan Gilligan wrote: but you could get arbitrary transmissions between 0% and 100% with good achromatic behavior and a much better contrast ratio than LCDs could provide. That is good to hear. No matter how useful the system could be if it added more aberation to the light already coming through five filters and ten glass elements a serious photographer would not use it (I have only read the term achromatic before and am still coming to grips with how different lenses can have different contrast ratios. They just don't tell you this stuff in Photography 101. :) ) Thanks for the answer Jonathan.
Paul Watson
Bluegrass
Cape Town, South AfricaMacbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Shog9: Paul "The human happy pill" Watson
-
I know this isn't what you are looking for, but some specialized video cameras have logrithmic light sensitivity. With then you can do such tricks as viewing the filament of a light bulb and the markings on the light bulb at the same time. You might find a Russian army surplus rig that does this kind of thing.
Stuart van Weele wrote: viewing the filament of a light bulb and the markings on the light bulb at the same time Crumbs, that is good, film could never handle that without an intermediary. Stuart van Weele wrote: You might find a Russian army surplus rig that does this kind of thing. *Paul pops down to his local friendly eastern europe black market... hmmm WMDs, WMDs, tanks, WMDs, APCs, WMDs, more WMDs, aaahh, a logrithmic light sensor, perfect, oh and throw in the AK, thanks.* ;) Thanks Stuart. I left the word "logrithmic" back in my failed math career but will dredge it up to figure out what the heck you mean. :)
Paul Watson
Bluegrass
Cape Town, South AfricaMacbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Shog9: Paul "The human happy pill" Watson
-
Sounds like an idea that I had once for a dynamic sunshade in a car. Build the windshield so that it could position a variably sized opaque circle right over where the bright center of the sun was coming through the window. Track the position of the drivers head so that it would move with them and always be between their face and the sun. Could never figure out a way to do it.
Paul Watson wrote: "At the end of the day it is what you produce that counts, not how many doctorates you have on the wall." George Carlin wrote: "Don't sweat the petty things, and don't pet the sweaty things." Jörgen Sigvardsson wrote: If the physicists find a universal theory describing the laws of universe, I'm sure the asshole constant will be an integral part of that theory.
Ray Cassick wrote: dynamic sunshade in a car. Dude I had such a similar idea awhile back. I am sure we are not the only ones though and by this it is obvious that eyeglass sunshade makers are supressing the idea (much like Wilkinson Sword have supressed the life-time razor blade) to ensure we actually still have a use for sunshades :-D My idea was that light sensitive material which some glasses use. It is spread out across the top of the windscreen and goes darker in the most directly bright spots (though how it knows that is beyond me! :-D ) I got the idea when I noticed my dads Toyota Corolla had a shaded strip along the top of the glass. Not many cars have it and it is a life saver in bright sunlight.
Paul Watson
Bluegrass
Cape Town, South AfricaMacbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Shog9: Paul "The human happy pill" Watson
-
Ray Cassick wrote: dynamic sunshade in a car. Dude I had such a similar idea awhile back. I am sure we are not the only ones though and by this it is obvious that eyeglass sunshade makers are supressing the idea (much like Wilkinson Sword have supressed the life-time razor blade) to ensure we actually still have a use for sunshades :-D My idea was that light sensitive material which some glasses use. It is spread out across the top of the windscreen and goes darker in the most directly bright spots (though how it knows that is beyond me! :-D ) I got the idea when I noticed my dads Toyota Corolla had a shaded strip along the top of the glass. Not many cars have it and it is a life saver in bright sunlight.
Paul Watson
Bluegrass
Cape Town, South AfricaMacbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Shog9: Paul "The human happy pill" Watson
Paul Watson wrote: My idea was that light sensitive material which some glasses use. Even better would be something like those auto-darkening welding masks, since they react more quickly. But as Ray mentioned, you'd still need a way to track the driver's head, else the whole thing would go dark...
- Shog9 -
Fat and soft, pink and weak / Foot and thigh, tongue and cheek You know I'm told they swallow you whole / Skin and bone. - Queens of the Stone Age, Mosquito Song
-
Yes, they let light through. Think overhead projectors. For example: http://www.v-lyte.com/benefits_tr.htmhttp://www.v-lyte.com/benefits_tr.htm[^] Here's a web site with cute pictures on how front light vs. back lighted LCD's work: http://www.minebea-ele.com/en/product/lighting/E_1000/E_1001.html[^] Now, I don't think anybody has done this as a camera lense adapter. Sure would be interesting. What about two or more polizared pieces of glass rotated at various angles to control the light density? Though I haven't heard of anyone doing this for regions of the field of view. Marc Help! I'm an AI running around in someone's f*cked up universe simulator.
Sensitivity and ethnic diversity means celebrating difference, not hiding from it. - Christian Graus
Every line of code is a liability - Taka Muraoka
Microsoft deliberately adds arbitrary layers of complexity to make it difficult to deliver Windows features on non-Windows platforms--Microsoft's "Halloween files"Marc Clifton wrote: What about two or more polizared pieces of glass rotated at various angles to control the light density? The thing I am looking for is variable edges. Light density can be controlled by stacking filters and other tricks. But so far any edge filters have static edges and areas, nothing you can adapt to each scene as needed. Thanks for the those links. Obviously I should have thought about projectors, thanks :)
Paul Watson
Bluegrass
Cape Town, South AfricaMacbeth muttered: I am in blood / Stepped in so far, that should I wade no more, / Returning were as tedious as go o'er Shog9: Paul "The human happy pill" Watson