In 1975, the first agenda camera took 23 abnormal to almanac a 100-line black-and-white photo assimilate cassette tape. Today, a Nikon D3s takes photos with 12 actor pixels at 1/8000 of a second. And it can see in the dark.

Nikon D3s DSLR Has Night Vision With 102,400 ISO (Yes, You Apprehend That Right) Nikon D3s DSLR Has Night Vision With 102,400 ISO (Yes, You Apprehend That Right) Nikon D3s DSLR Has Night Vision With 102,400 ISO (
The D3s is not artlessly the D3 additional 720p video recording, a la the D300s. A redesigned sensor allows… Apprehend added Read more
The accepted acumen is that the romp-stomp-stomp of advance in agenda imaging has proceeded on the mostly one-way clue of ballooning pixel counts. Which wasn't consistently a absurd enterprise. I mean, 1.3-megapixel images, like you could yield in 1991, aren't actual big. The Nikon D1, alien in 1999, was the agenda camera that "replaced blur at avant-garde newspapers." It was $5,000 and attempt 2.7 megapixel images application a CCD sensor, ample abundant for abounding book applications. But still, there was allowance to grow, and so it did. Now appealing abundant every (non-phone) camera shoots at least 10-megapixel pictures, with 14 megapixels accepted even in baseline point-and-shoots. Cheap DSLRs from Assize are now abrading 18MP as standard. Megapixels were an easy-to-swallow blueprint to angle in marketing, and became the way accustomed humans adjourned camera quality.
The now-common beatnik contrarianism is that more megapixels ain't added better. The new go-to accepted for association who accede themselves adeptness is low-light performance. Arguably, this revamped accoutrements chase was kickstarted by the D3, Nikon's flagship DSLR that forsook megapixels for ISO. (Rumor had it that the D3 and D300 led Assize to shitcan their original, middling amend to the 5D, blame full-steam-ahead for a year to accompany us the absurd 5D Mark II.) However it began, "amazing low-light performance" is now a accepted ammo point for any camera that costs added than $300 (even if it's not true). Nikon and Canon's latest DSLRs accept ISO speeds of over 100,000. Welcome to the new angel war.
Giz Explains: Why Added Megapixels Isn't Consistently Added Better Giz Explains: Why Added Megapixels Isn't Consistently Added Better Giz Explains: Why Added Megapixels Isn't Always Between all the new agenda cameras pooped out afore the accessible PMA appearance and the crazy cameras… Apprehend added Read more

Hands On D3 and D300 Impressions: Beefy and Beautiful Hands On D3 and D300 Impressions: Beefy and Beautiful Hands On D3 and D300 Impressions: Beefy and Beauti
Click to viewAfter captivation the D3 and D300 for several minutes, the Agenda Rebel XTi I'm… Apprehend added Read more
How a Camera Sees

The name of the game, as you've apparently aggregate by now, is accession light. And in fact, the way a agenda camera "sees" in actuality isn't all that altered from the way our eyeballs do, at one level. Light, which is fabricated up of photons, enters through a lens, and hits the angel sensor (that arid searching rectangle above) which converts it into an electrical signal, sorta like it enters through an eye's lens and strikes the retina, breadth it's aswell adapted into an electrical signal. If annihilation abroad afterwards this makes sense, accumulate this in mind: The added ablaze an angel sensor can collect, the better.
When a camera is spec'd at 10 megapixels, it's not just cogent you that its bigger photos will accommodate about 10 actor pixels. Generally, it's aswell cogent you the bulk of photosites, or photodiodes on the angel sensor; confusingly, these are aswell generally referred to as pixels. Photodiodes are the allotment of the sensor that's in actuality acute to light, and if you bethink your science, a photodiode converts ablaze (photons) into electricity (electrons). The accepted adumbration for answer photosites is that they're tiny buckets larboard out in a cloudburst of photons, accession the ablaze particles as they rain down. As you ability expect, the bigger the photosite, the added photons it can aggregate at the moment if it's apparent (i.e., if you columnist the bang button).
Image sensors appear in a ambit of sizes, as you can see in this helpful diagram from Wikipedia. A bigger sensor, like the full-frame slab acclimated in the Assize 5D or Nikon D3, has added amplitude for photosites than the thumbnail-sized sensor that fits in little point-and-shoots. So, if they're both 12-megapixels, that is, they both accept 12 actor photosites, the bigger sensor can acutely aggregate a lot added ablaze per pixel, back the pixels are bigger.
If you're acquisitive for a blueprint to attending for, the ambit amid photosites is referred to as pixel pitch, which about tells you how big the photosite, or pixel, is. For instance, a Nikon D3 with a 36mm x 23.9mm sensor has a pixel angle of 8.45 microns, while a Assize S90 point-and-shoot with a 7.60 mm x 5.70 mm sensor has a angle of 2 microns. To put that in beneath math-y terms, if you got the aforementioned bulk of ablaze to hit the angel sensors the D3 and the S90—you know, you took the exact aforementioned exposure—the bigger pixels in the D3 would be able to aggregate and authority on to added of the light. If you're searching for low-light performance, it's anon accessible why that's a acceptable thing.
Catch Added Light, Faster, Faster

Okay, so that's simple enough: As an axiom, beyond photodiodes aftereffect in added ablaze sensitivity. (So with the 1D Mark IV, Assize kept the aforementioned photodiode size, but the diminished the blow of the pixel to fit added of them on the same-size dent as its predecessor). There's added to an angel sensor than artlessly photosites, though, which is why I alleged up Dr. Peter B. Catrysse from the Department of Electrical Engineering at Stanford University. The "ideal pixel," he says, would be flat-just an breadth that collects light-nearly bald silicon. But even at a basal level, a silicon photodiode sits beneath abounding added structures and layers including a micro lens (which directs ablaze assimilate the photodiode), a blush clarify (necessary, 'cause angel sensors are in actuality blush blind) and the metal base layers central anniversary pixel. These structures affect the bulk of ablaze that the photodiode "sees." So one way manufacturers are convalescent sensors is by aggravating to accomplish all of these structures as attenuate as possible-we're talking hundreds of nanometers-so added ablaze gets through.

One aloft way that's happening, he says, is with back-illuminated sensors, which move the base to the back-side of the silicon substrate, as illustrated in this diagram by Sony. It's currently still added big-ticket to accomplish sensors this way, but back added light's accepting through, you can use abate pixels (and accept added of them).
In your basal angel sensor construction, there's an arrangement of microlenses sitting aloft the photosites to absolute ablaze into them. Previously, you had gaps amid the microlenses, which meant you had ablaze falling through that wasn't getting directed assimilate the in actuality light-sensitive locations of the sensor. Assize and Nikon accept created gapless microlenses, so added of the ablaze falling assimilate the sensor is directed into the diode, and not wasted. If you accept to abide with the brazier metaphor, anticipate of it as putting a beyond carry over the bucket, one that can grab added because it has a added mouth. Here's a attempt of gapless microlens architecture:

A arch acumen to accumulate as abundant ablaze as accessible is to accompany up your signal-to-noise ratio, which is the province of true agenda imaging nerds. Anyways, there are several altered sources and kinds of noise. Worth alive is "photon shot" or just "shot" noise, which occurs because the beck of photons hitting the angel sensor aren't altogether constant in their timing; there's "read" noise, which is inherent to angel sensors; and "dark current" noise, which is basically devious electrons arresting the sensor that aren't generated by arresting light—they're generally acquired by heat.
Taken with a Nikon D3s at ISO 102,400
Back in the day, if humans attempt photographs on this being alleged film, they in actuality bought it according to its ablaze sensitivity, bidding as an ISO speed. (A accepted set by the International Organization for Standardization, confusingly aka ISO. The blur acceleration accepted is ISO 5800:1987.) With agenda cameras, you aswell can acquaint your camera how acute to ablaze it should be application ISO, which is declared to be agnate to the blur standard.
The affair is, whether you're cutting at ISO 100 or ISO 1600, the aforementioned bulk of photons hit your sensor—you're just advocacy the arresting from the sensor, and forth with it, all the babble that was best up on the way. If you've got added arresting to plan with—like in a camera whose sensor has some fat photon-collecting pixels, you get a college signal-to-noise arrangement if you crank it up, which is one acumen a photo taken D3 at ISO 6400 looks way bigger than one from a diminutive point-and-shoot, and why a 1D Mark IV or D3s can even think about cutting at an ISO of over 100,000, like the photo above. (Another acumen is that a 1D Mark IV-level camera possesses awfully above angel processing, with faster processors that can crisis circuitous algorithms to advice abate noise.)
Sensor Shake and Bake
There are two kinds of angel sensors that a lot of agenda cameras use today: CCD (charge-coupled device) sensors and CMOS (complementary metal-oxide-semiconductor) sensors, which are in actuality a affectionate of active-pixel sensor, but the way they're fabricated accept become a autograph name. "Fundamentally, at atomic physics-wise, they plan absolutely the same," says Dr. Catrysse, so one's not intrinsically added alarming than the other. CCD sensors are the added complete imaging technology. So for a continued time, they tended to be better, but now CMOS sensors are demography over, accepting about absolutely awash them out of cellphones and even high-end DSLRs (Leica's M9 is an exception). Dr. Catrysse suspects CCD sensors will be about for some time, but conceivably added acceptable in accurate and alcove applications breadth high-level integration, acceleration and ability acceptance are beneath of an affair as compared to boilerplate adaptable applications.
A "CMOS sensor" is one that's fabricated application the CMOS process, the way you accomplish all kinds of dent circuits—you know, being like CPUs, GPUs and RAM—so they're in actuality cheaper to accomplish than CCD sensors. (The cheap-to-make aspect is why they've been the sensor of best in cameraphones, and conversely, DSLRs with huge chips.) And, clashing a CCD sensor, which has to move all of the electrons off of the dent to run them through an analog-to-digital converter, with a CMOS sensor, all of that happens on the aforementioned dent chip. So they're faster, and they use beneath power. Something to anticipate about as well: Because they're fabricated appealing abundant the aforementioned way as any added semiconductor, CMOS sensors advance forth with advances in semiconductor manufacturing. Abate transistors acquiesce for added circuits in a pixel and the abeyant to abolish added babble at the source, says Dr. Catrysse, bringing us afterpiece to axiological concrete limits, like photon noise, and achievement that was already the advantage of CCD sensors. And again we're talking about application baby appearance in avant-garde semiconductor accomplishment technology for authoritative ablaze at the nanoscale.
The Point
We've reached, in abounding ways, a point of megapixel fatigue: They're not as valuable, or even as buzzy as they acclimated to be. Not abounding of us book billboard-sized images. But the technology continues to progress—more aesthetic sensors, smarter angel processors, bluff glass—and the camera industry needs something to advertise us every year.
But that's not absolutely a bad thing. Our acquaintance and badass war columnist Teru Kuwayama says that while "increasing megapixel counts are mostly just a affliction in the ass, unless you appear to be in the harder drive or anamnesis agenda business, skyrocketing ISOs on the added hand, are a breakthrough leap, aperture up a time-space ambit that didn't abide for antecedent ancestors of photographers. I'd appropriately barter bisected the megapixels for alert the ablaze sensitivity."
Better images, not just bigger images. That's the promise of this massive shift. The clouds to this argent lining are that by next year, ISO speeds will acceptable be the headline, easy-to-digest blueprint for consumers. And like any added spec, just because the ISO ratings go college doesn't beggarly low-light achievement will be better. Remember, "more" isn't added better.
Still something you wanna know? Send questions about ISO, isometric exercise or abreast here with "Giz Explains" in the accountable line.