The Nobel Prizes that go into your Digital Camera

My Camera - not so long ago

I am a photography enthusiast and the constant evolution of technology in the world of cameras fascinates me. Therefore I thought of writing this article. If you are interested you can see the pics I have taken here.

The world of photography has seen a rapid transformation in technology within the last few decades.

In the 1980's as a kid, I had a completely manual HotShot 110S camera that gave me the freedom to capture any beautiful moment. It required a plastic film like the one you see in the picture on this page. Operating the camera involved learning to load the film into the camera just right, pulling the plastic reel enough so the film would fit into the grooves of the gear before it was ready to roll. To take the next shot you had to turn a mechanical dial to advance the reel to the next section of the film that would capture the frame. A mechanical counter displayed how many images were shot.You had more or less 36 chances to get the shot right before a reload of a new film roll was required.

Patience was the key. To see the results, you had to wait till the time the camera roll was processed in a lab where a technician would run the film (negatives) through a series of chemical reactions to develop the film.

Therefore mastering the art of photography took much more experimentation and time than today where the results can be seen instantaneously.

The science behind a photographic film

The photographic film, I referred to, is used only by certain hobbyists today. The technology is outdated with no market. Such a film is a stack of many layers with chemicals on it. The layers are bound by a variant of the edible gelatin (that is made by processing animal skin, cartilage, and bones as its ingredients).

Once the shutter is clicked, the photons pass through the layers triggering several chemical reactions.

Different layers have different purpose like filtering the light, managing the light sensitivity, and controlling the chemical reactions.

There would be different films for color or Black & White photography because of the difference in processing needed by the layers of film.

Such films are available even today for photography enthusiasts who out of the interest use the films-based technology.

Spectral Sensitizers and Dye Couplers

The film has organic molecules known as spectral sensitizers required for absorbing the right information for recording the color information. It is the layer with the coating of "silver halide crystals" (= silver-nitrate + chloride, bromide and iodide) that is the photo-sensitive layer that registers the impact of the photons impacting it.

This exposed film is used as a 'negative' and processed further to develop the positives or the prints that were showcased finally in photo albums or photo frames. The processing involves treating the exposed silver on the film and the usage of dye couplers for the reproduction of colors. Instant film cameras also use a variation of films and processes described with certain differences. In essence the film used in instant photography is also dependent on chemical reactions on the layers of the film.

My Camera - today

Over the course of years my cameras changed with technology. I still remember the excitement of my first digital point and shoot camera where we could see the result immediately on the screen and a film was no longer needed (it was a Samsung point and shoot, it was followed by Fujifilm and Sony compact cameras).

The transition to DSLRs was a really exciting change. My first DSLR was Canon 550D aka EOS Rebel T2i followed by Canon 200D Mark 2 and now a beautiful awe-inspiring Canon 5D Mark 4.

All of these cameras have been my best friends on my life journey capturing beautiful moments to cherish.

So what innovations led to this transformation that have made our photography experience lot more efficient and exciting?

This magical transformation is made possible by scientists who studied light better and invented devices called "CCD and CMOS sensors".

Making the transformation possible: The Nobel Prizes in Physics

There are two Nobel Prizes in Physics that highlight the technology that goes into the making of the modern digital cameras.

The first one is of course for the laws of Photo-Electricity for which Albert Einstein won the Nobel Prize in physics in 1921.

The second one is for the work done by Willard S. Boyle and George E. Smith from Bell Laboratories. They invented the imaging semiconductor circuit known as the Charge Coupled Device digital sensor in 1969. It is the technology that led to the creation of the electronic eye of a digital camera. For this work they were awarded the Nobel Prize in Physics in 2009. This invention has helped in getting high resolution images in the fields of astronomy, medicine and photography.

Electronic Eye of the Digital Cameras - CCD and CMOS sensors

The technology evolved and disrupted the way pictures were taken. The image capturing technology quickly moved from chemicals based films that needed longer processing times to electronics based using CCD and CMOS sensors. These sensors capture the image information that is transferred to a memory card. Thanks to these technologies we can see the pictures instantly.

The great pictures your mobile phone takes today are courtesy of these inventions (it uses a CMOS sensor).

Charge Coupled Device (CCD)

CCD is a technology that has integrated circuits (IC) on top of a block of photo-sensitive Silicon. There are numerous sections as part of the IC that store the image information when light strikes these sections. Each such section is called as a photosite or the more familiar pixel. This impression of photons and its influence on the section that is electric in nature is possible due to the laws explained in the photoelectric effect.

The photoelectric effect is the emission of electrons or other free carriers when light shines on a material. A charge proportional to the light intensity is induced when photons hit these pixels . The information stored in millions of such pixels is initially passive and is transferred row by row to a processor that processes the image. It is then transferred to a memory card to store the image. All of this is done without the use of any wires to make the transfer as lossless as possible.

Image courtesy: Wiki Commons: https://en.wikipedia.org/wiki/Charge-coupled_device

Take a look at this video that explains the working of a CCD sensor in greater detail.

Complementary metal–oxide-semiconductor (CMOS)

CMOS technology has a slight difference in the way the charge in pixels is transferred to the memory card. Here the individual sections (pixels) that capture image information (through photons impacting them) have added ability of being self contained units for signal amplification and processing. That is why such CMOS sensors are called as Active Pixel Sensors. This processed information is transferred to a storage device with tiny wires (as opposed to a wire free transfer process in CCD based sensors).

From the initial CCD sensors, today the sensor of choice for most consumer targeted digital cameras and mobile phones is CMOS for the advantages it offers in terms of its cost, size and impact on battery life.

While this article has been a simple explanation of various image capturing technologies there is quite some complex innovative work that goes into the process of the modern imaging sensors. If you are interested in a deeper explanation here is an excellent video that I highly recommend.

Next time we hold a digital camera in our hands or watch a high resolution image of a galaxy or of a planet sent from an eye in the sky we know we are enjoying the work of some of the finest minds who received the most celebrated and recognised Nobel prize for their contributions in the field of Physics greatly benefiting the world of photography.

I am so filled with gratitude to the numerous scientists and innovators who have made the experience of photography a joy!