(Still) Keeping the 'X' in 'Xmas'

 

By Ctein

Once again, a Salubrious Solstice to one and all, and my best wishes to you and hopes that you are enjoying this holiday season, for whatever definition of "holiday" works for you.

Last year, I described the wonders of "X" in a somewhat rarefied way. This year I'm going to be more down-to-Earth in my talk of the unknown. Namely, what sorts of digital camera improvements you may expect to find the [semi-mythical gift-giver of choice] putting in your [personal gift receptacle of choice] in the next double-handful of years.

This is not a wish list. Every one of these goodies is sufficiently mainline and part of the normal manufacturing track that I am certain they will all show up in your digital camera...unless current technology improves so much that it makes some of them unnecessary. That's the unknown part—either you'll get these goodies or you'll get something even better. It's horrible living with uncertainty, isn't it?

Here's the shape of shinies to come:

Back-illuminated thinned sensors: These have twice the collection efficiency of standard sensors, and they've been in common use in scientific instruments for many years. You haven't seen them in commercial cameras because thinning the substrate has been expensive. New manufacturing patents show how to do this on a production basis. It gets you a factor of two improvement in ISO, across-the-board, but it's especially important for small-pixel sensors.

Deep well insulating sensors: A problem with sensor arrays is electron leakage between the pixels. All sensors suffer from this. It reduces low-light sensitivity, decreases sharpness, and degrades color rendition. A new design adds a secondary well layer beneath the pixels that insulates them. Hard to estimate exactly how much this will improve things, but I would guess about half a stop in low light performance, plus better sharpness and color.

Non-Bayer filter arrays: Bayer filters are a good compromise when you have a moderate number of pixels. There are efficient at capturing spatial detail, and computationally simple. They have many disadvantages: poor overall light collection, horrid aliasing problems, and they shortchange blue sensitivity, especially bad for available-light work under normal indoor lights.

Other filter arrays solve all these problems. This is nothing new; Kodak and other companies have been doing this since the early days of high-quality digital cameras. As pixels approach the micron size (and there are very good reasons for them to do so, despite some of the naysaying you've read) quasi—random filter arrangements will improve sensitivity, sharpness, and reduce noise.

Adaptive pixels: Good digital cameras already capture an 11–12 stop luminance range, but there would be some real advantages to capturing a 20-stop range (total exposure freedom, for one thing). Adaptive pixels that alter their response depending on the intensity of light that hits them exist in laboratory sensors; they'll hit the mainstream within a decade, unless conventional designs get so much better that nobody cares.

GRIN optics: "GRadient INdex (of refraction)" lenses have an index of refraction that changes as you move out from the center of the lens. Scanners already use GRIN lens arrays to relay the image from the platen to the sensor. A few commercial camera lenses have already been designed with GRIN elements, but there are problems still to be solved in making large elements cheaply and characterizing them well in production. But, as with aspheric surfaces, which were similarly exotic decades ago, these will gradually penetrate optical designs.

Diffractive optics: Gratings embossed onto the surface of the lens can radically alter things like chromatic and spherical aberration, which are otherwise difficult to correct well. We already have limited diffractive optics. Like GRIN, this is going to improve a lot over the next decade and we're going to get very innovative designs.

Combination optics: What happens if you combine GRIN, diffractive gratings, and lens surfaces of arbitrary curvature? You get single lens elements that perform as well or better as your typical triplet. Imagine what you could do, in terms of lens weight, aperture, and size, if you could cut the number of lens elements by a factor of two or three and make each element thinner and lighter to boot.

This is all off-the-shelf in the next few-to-ten years. I didn't even get into the edgy stuff, like quasi-particle single photon spectral detection, metamaterials, and other exotica, whose future is entirely unknown.

Anyone who tells you that camera image quality is near to topping out simply has no idea of what's waiting in the wings. Salubrious Solstice!

______________________

Ctein

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Comments

[Eolake Stobblehouse]

This all sounds very cool, thanks.

[bobdales]

... which means as these goodies happen we're not going to like whatever we buy today so don't agonize over your buying decision now, you'll change it.
bd

[Miserere]

A very nice read, Ctein; you topped up my geek reserves for the day. You've also convinced me to not upgrade my camera this decade. In fact, I've decided to give up photography altogether until I can use a 20-stop camera; anything else is simply to rudimentary for me. ;-)

[yz]

That was a breathtaking list.
Nowadays sensors are just amazing even the older designs, surely. And then your simple list shows us that the real sweet things are just coming :)
That makes me skip another few generations of cameras (and stay with my "good old" 20d further) and wait for completely new things. I'm not in a hurry, I can wait (and the regression helps me waiting anyway:)

[Clesys]

Merry Christmas to you!

[Eolake Stobblehouse]

"random filter arrangements will improve sensitivity, sharpness, and reduce noise."

The latter two I can see, but sensitivity too?

[John R]

Bah, humbug, I still love film and my Nikon FA and all my manual lenses. Though I no longer challenge the fine improvements in digital photography, the new digital camera only seems to get more complicated all the time. Love your writing, thoughts and the trouble you take to delve into these matters.

John R.

[Richard Man]

You know, the cynic in me says neither one of the Big Two will be a trailblazer in any of these technologies. More megapixels yet, but I bet it will take someone else to prove the concepts first.

[Eolake Stobblehouse]

Re the illustrating photo: it's nice to see that not all Americans over-decorate for Christmas like the cliche goes.

[john robison]

In the mid 70's I felt that 35mm cameras were at 90% of their potential. With the introduction program automation, controlling both shutter-speed and aperture what else could the designers come up with? I and perhaps many others were blindsided by the developments in computer processing power and electronic sensors that has changed my hobby beyond recognition. Now it seems that the revolution continues unabated. Of your list the only things I've heard about is the non-bayer array and GRIN optics. (Olympus experimented with an 85mm f1.4 GRIN lens in the 90's but was not able to get it into production). I don't consider myself a Luddite but I find the fast pace of technology somewhat disturbing and disorienting. I know I'm not alone in this disquieting feeling and can't put my finger on why exactly it happens. It's just that there is a certain comfort in picking up my old cameras and the arrival in the post of my first dSLR did not engender near the excitement I felt a couple of months later when a 43 year old camera I won on E-bay appeared at my address. I think I'm just waiting for the right camera to arrive on the digital scene, and in fact, the Panasonic G-1 has piqued my interest. It's the first time I've actually wanted to get my hands on a digital since their start to ascendency in the late 90's. Yes, I know, do what pleases you and don't worry about all the esoteric developments in the pipeline. Easy to say, hard to do.

[Ctein]

Dear Eolake,

Pixels smaller than 1.5 microns do not add anything to sharpness in sensors 1/2 (35mm size) or larger. This leaves designers free to use the 'extra' pixels for things other than resolution enhancement. Going to non-regular filter patterns also frees up design parameters.

For example, here are two filter ideas that have been suggested for markedly higher sensitivity:

-- panchromatic emulation: assign pixels in inverse proportion to the sensor's spectral sensitivity. Silicon sensors have really low blue sensitivity; they should have 2-3 times as much area devoted to blue as to red.

-- luminance channels: 'salt' the RGB array with pixels that are either unfiltered (save for IR) or have a broad-band photopic filter. Use those to capture pure luminance info in a scene.

Both of these are less artifacty in non-repeating patterns.

pax / Ctein

[Ctein]

Dear Richard,

The cynic in you is already wrong. This isn't the trailblazing stuff. This is the routine stuff. Some of it's even been done in the past (guess who used non-Bayer arrays?)

Again, I emphasize, this is not the exotica.

pax / Ctein

[Hugh Crawford]

One of the long term technologies that have me excited are quantum dots om polymer substrate sensors.
The interesting things about this are that they could have much higher resolution , random non bayer arrays , much higher sensitivity etx.

The most interesting two things though are that since they are on a polymer ( plastic) substrate rather than silicon they could be really cheap to make , you can make them really large, and with the much higher resolution map out any bad receptors for very high yields. Even more interestingly they can be made on spherical surfaces since you don't have to slice the substrate off of a big chunk of silicon. With a concave spherical sensor , with lenses that create a spherical real-image , most of the hard problems of lens design go away, or at least the expensive ones.

With cheap fast big sensors , you could see practical digital large format cameras, some really interesting lens designs that don't need to correct curvature of field , spherical aberrations , coma etc.

http://www.wired.com/science/discoveries/multimedia/2008/12/gallery_photodetector?slide=1&slideView=8

Of course this technology would also work really nicely with synthetic aperture photography, my favorite long term technology , which would render lens design a software problem.

With synthetic aperture photography you would get "raw" files that were so raw that you could determine the lens design , f/stop , point(s) of focus etc. at the time that you process the file.

A F/.01 software lens with after the fact programmable bokeh. Think about that.

[hugh crawford]

"(guess who used non-Bayer arrays?)"
Ok, I'll bite, would the earliest be Autochrome, patented in 1903 by the Lumière brothers ?

[Andrew]

Thanks for these interesting snippets, Ctein.

One of these technologies stood out because it has been available for years - diffractive optics. It has continually surprised me that we have not seen more use of this technology since it has already brought big savings in size and weight to telephoto lenses from Canon.

Is this due to cost or is it simply that Canon is not challenging the user base enough with some intersting designs?

We wait in awe for a 20 stop DR sensor - maybe I shoudl delay the upgrade from a 20D to something a little more zappy :-)

Thanks and Merry Whatevers
Andrew

[Ctein]

Dear Hugh,

There's a lot of very interesting exotica out there. Along with what you mentioned, which is really interesting stuff, I'm looking to superresolving metalenses, pixelless sensors, and photon-counting/energy-measuring sensors.

All stuff off the current manufacturing paths, so no idea of when it sees our front doors, if ever.

The ultimate future is indeed computational/synthetic photography. Everything we're getting now is just the transitional phase, mimicking of analog methods in silicon and software. It's not the smart way to do it. 50 years from now (40? 30? 20?) lenses and 'raw' photographs will not be recognizable as such by folks today.

pax / Ctein

[Jay Moynihan]

A trivia digression.

I went back and saw your post from last year Ctein. So, thought would add this X trivia.
Some folk think that using "Xmas" is a modern thing, derogatory of using "Christmas".
But, it ain't that simple.

The modern usage of Xmas does come from advertising, specifically, newspaper ad copy (print big, save space and fee) during the late 1800's.
But, actually, Xmas, is older than Christmas.

Christmas.

"Christ" (from the Greek "Christos", aka Yoshua Ben Josepf, Jesus, etc), and "mas", a Saxon (Germanic) word for celebration, or party.

But that is relatively new.

Xmas.
Old.
"XP" was the abbreviation used in the early days of Christianity, for the name of Christ. it shortens The labarum, often called the Chi-Rho, a symbol, you can still find on th vestments of some practioners.

As the religion spread into greater Europe the P was dropped, and tied to the widely used word Mas. Hence Xmas.

It eventually became the name for the major commercial (shopping) holiday in the empire on December 25, Dies Natalis Solis Invicti, "the birthday of the unconquered sun", (Roman solstice celebration).

Glad Sol Invicti everyone!

[Eolake Stobblehouse]

"superresolving metalenses"

What's that, pray tell?

[WeeDram]

Oh boy, I can't wait! Hundreds of thousands of new "photographers", so excited by breakthrough technology ... posting gazillions of crap pictures on flickr, smugmug, photobucket. Yay!

We have face detection; when will someone invent junk detection that triggers camera lock up? ;)

[ctein]

Dear Wee,

Well, that post wins the "Scrooge" award for the season.

Is someone MAKING you look at all those photos? If not, then so long as they're making the photographers happy, it's really not any of your concern.

Photography is the preeminent folk art form of the 20th and (so far) the 21st centuries. So long as the people practicing it are enjoying the results, it's not your place to diss them.

pax / Ctein

[ctein]

Dear Andrew,

Speedy adoption of these lens technologies doesn't happen because they're all considerably more expensive to fabricate than ordinary lenses (to begin with), design tools have to catch up, and it can be tricky to maintain quality control and to accurately characterize the deviations from specification in commercial runs. That's why these things get invented well before they appear in camera lenses and why the first lenses to use them tend to be exotic and/or expensive ones.

~ pax \ Ctein
[ Please excuse any word-salad. MacSpeech in training! ]
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-- Ctein's Online Gallery http://ctein.com 
-- Digital Restorations http://photo-repair.com 
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[ctein]

Dear Eolake,

Metamaterials let you build optics that resolve better than normal diffraction limits. Entirely capable of doing seemingly impossible things. In fact when these materials were proposed around the turn of the decade, some reputable physicists thought it would be impossible to fabricate them because the consequences of doing so would be so outrageous.

Turns out that's not the case; they can be made. They have a long way to go before they'll appear in ordinary photographic systems. But at some point lens designing is going to get very, very weird.

~ pax \ Ctein
[ Please excuse any word-salad. MacSpeech in training! ]
======================================
-- Ctein's Online Gallery http://ctein.com 
-- Digital Restorations http://photo-repair.com 
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