专讗砖讬 English Steven Sasson – The Dawn of Digital Photography

Steven Sasson – The Dawn of Digital Photography


You might not have heard his name but you can be sure you have used his invention and watched countless images created by it for well over a decade. MegaPixel is extremely proud to interview Steven Sasson – the inventor of the digital camera.

Very few people can rightfully claim to have changed the history and development of photography. Out of those less than a handful are still with us today and Steven Sasson is one if not the most important of them.

Over the past few years Steven Sasson had gave quite a few interviews to the international media answering various questions about his role in the development of the digital camera during his many years working for Kodak. In the following interview we included several questions that we hope will illuminate a number of new and unknown facts about the way the digital camera was created, as well as give a broad look at its development.

Steven Sasson receives the National Medal of Technology and Innovation in 2010 (Credit: Ryan K. Morris/National Science & Technology Medals)

Interview with Steven Sasson

聽Q: Can you briefly describe the background which lead to the development of the first digital camera in 1975 in Kodak by you and your colleagues?

A: The project that resulted in the first digital camera was the result of a short conversation I had with my supervisor, Gareth A. Lloyd in late 1974.聽 We were working in the Kodak Apparatus Division research lab in Rochester N.Y. He asked if I would investigate the new CCD imaging device that had just become available from Fairchild corp.

It was a very open ended task and so I thought if we could investigate the imaging via an image capture type of device it would be interesting.聽 I decided to try to build a camera type of device that would store captured still images. I used a completely digital approach because it eliminated a great deal of mechanical complexity and would enable the construction of a all electronic capture and playback system using a conventional TV set.聽 It was a very small project that involved myself and a very talented technician 聽,Jim Schueckler.聽 We used many of the parts from the factory we worked in and the research lab parts stock to construct the system.

Q: You have mentioned elsewhere that the development of the first camera took about one year – what was the most complex part and how many people where involved in the project?

A: There were many issues we had to deal with. The CCD device itself was very new and no one had worked with this type of device before.聽 Constructing the camera in a portable device structure was difficult as we built our circuits only once in the prototype so it had to be easy to work on as well as have to be portable.聽 The digital architecture we came up required a large digital memory as part of the camera that had to store and hold the output of the (custom designed for this project) a/d converter at high speed and then read it out a slower rate to a in-camera digital recorder.聽 All of this was difficult to troubleshoot during the development of this device. Also, the playback device required storing a digital image, image processing via microprocessor (new at the time) and creating a NTSC standard video signal from the stored digital image.聽 We had never done any of this before so the learning curve was steep.聽 Lastly, realize that the entire system, camera and playback system, was designed and built without ever seeing any images during the year of development.聽 All progress was measured using oscilloscope measurements and digital voltmeter readings.聽 The only time we saw images was when the entire system was complete.

Historic image – the playback system from the original technical report (Credit: Steven Sasson/Kodak)

Q: How many prototypes did you developed and do they still exist and in working condition (are they still in Kodak's possession)?

A: Only a single prototype camera was built.聽 It still exists, unchanged from when it took it last image sometime in 1976.聽 It doesn鈥檛 function anymore for a number of reasons that include that the fact that the wire-wrap connections we used for the digital circuitry were meant only for temporary connections.聽 The camera is presently still at Kodak Headquarters in Rochester N.Y. with the intent to give it to a museum at some point in the future.

Q: Did other groups compete against you in developing the first digital camera (was it a "race" like the one to develop the first laser in the late 1950's) and how well did you know the work of the team at Texas Instruments in 1972?

A: To my knowledge no one at Kodak was attempting to build a camera and playback system like this at this time. When the head of the corporate research lab saw the demonstration of the system in 1976 he indicated that this system was unique. I did not know about the Texas Instruments proposal when I was working on this project and became aware of it when we applied for a patent on this concept ( 1976/ 1977).聽 The TI proposal was quite different as it was not digital and didn鈥檛 suggest the architecture we used here.聽 Instead it proposed a helical scan type of storage of a single frame from the device. I had considered this approach at the start of the project but rejected it because it didn鈥檛 allow me to actually build a portable device with no (few) moving parts. I also wanted to evaluate the imaging properties of the imaging system and this was greatly facilitated by it being in digital form.

Historic image – prototype digital camera from the original technical report (Credit: Steven Sasson/Kodak)

Q: Was the development of the camera announced by the press at the time or was it an internal Kodak project (and if so, when did the public first learned about it)?

A: No public description of any of this work was released until October of 2001. I described the camera and playback system for a newspaper article that appeared in the October 16, 2001 edition of the Rochester Democrat and Chronicle, a local newspaper.聽 This article also contains the first public photo of the original prototype.

Q: In the digital camera you have developed for Kodak you have used one of the first CCDs available from Fairchild Semiconductor – obviously they did not develop it especially for you – but since you have developed the first digital camera it's a bit unclear what was the original market for those early CCD sensors (I am guessing Fairchild Semiconductor had no idea what you were doing with their sensor?)

A: I believe the 鈥渦ltimate鈥 goal for the initial development of these devices was to replace the Vidicon tube for television cameras. These early devices found their first application in astronomical imaging because of their geometric stability and if the temperature were lowered (these applications allowed this) the noise performance could be improved.聽 It was about 10 years later when Kodak first demonstrated megapixel sized imagers with color filter arrays that would be suitable for still consumer photography.聽 To your last question, I had no direct contact with Fairchild after I purchased the initial devices for the project.

Q: The original CCD invented in 1969 was B&W only – did the Fairchild Semiconductor sensor you have used was capable of producing color images and how did it do that (after all the Bayer filter was only patented in 1976)?

A: These devices were only B & W sensors.聽 CFA鈥檚 [color filter array. I.G.] were developed in the 1980鈥檚 showing up on Kodak鈥檚 first megapixel imager in 1986.

Steven Sasson holding the original digital camera prototype (Credit: Steve Kelly/Kodak)

Q: What was the original sensor resolution and what made you speculate at the time that 2MP should be the lower limit for digital camera mass adoption?

A: The first sensor (Fairchild CCD 201) had a resolution of 100 x 100 鈥減ixels鈥. It was a interline architecture which means that this resolution was obtained through two interfaced 鈥渇ields鈥 that were read out in succession.聽 The 2 mp resolution goal came from some estimates of the image quality equivalent for a frame of 110 format consumer film (a consumer format at the time).聽 This was the lowest quality I could find that I could call consumer quality, If I had used 35mm film the resolution the number would have been a great deal higher.

Q: Did you know Willard S. Boyle and George E. Smith at the time and did you have a chance to meet with them over the years since then?

A: Unfortunately I have never had the honor of meeting either man. I have given talks at venues that one of them had given talks in earlier years. I did read about the invention of the CCD at the time of my early work but learned a good deal more about them when they got their well deserved Noble Prize.

Q: How did you call the camera (did it even have a name or was it just a "digital camera") and why was it blue?

A: One of the other early contributors to this project was a technician named Bob DeYager and he suggested painting the 鈥渂ud鈥 box that we used to hold the CCD and optics assembly on the top of the camera. The unpainted aluminum box would have shown all kinds of oil and stains from handling. He chose blue because that was the color paint we had.聽 I had no official name for the camera, although I did call it some uncomplimentary things when it stopped working (which it did frequently…).

Q: What was the first image (actually I think you stated that it was the second) you took, can you tell the story behind it, do you still have a copy of it?

A: The actual first test was a still of a piece of cardboard that was black on one side and white on the other. The first image was taken of a lab technician that was working down the hall from our lab.聽 There was a problem with the display so that the image was distorted when we first viewed it.聽 I had made a mistake in the retrieving the bits coming off of the tape.聽 When I corrected the error the young lady鈥檚 head and shoulder鈥檚 shot was correctly displayed and very recognizable.聽 That was in early Dec , 1975. I do not have that image, we had no way to store these images and had to reuse the tapes for the experiments.

Q: Can you estimate how much did the project cost at the time and more importantly how much did the components of the first camera cost at the time?

A: Most of the parts came from around the lab and parts (optics assembly) taken from used parts bins from the factory. The CCD was the most expensive purchased part for the camera and I would guess each device cost a few hundred dollars. The tape drive used in the camera was purchased and probably cost in the range of 200 dollars or so. The playback system was based on a purchased microprocessor development system.聽 That was a several thousand dollar purchase which was to be used for several projects within the laboratory after it was used in our project.

Q: Why did you choose a cassette tape as the storage medium for the camera and why did you choose only 30 images (how many images can a cassette actually hold)?

A: I chose 30 images per tape to make the system look a bit like the present film systems (24 or 36 exposure film rolls).聽 I could have set the recording density much higher (10 x) but that would have confused the issue and created more questions about storage of the images (we were pre home computer in these days).聽 I chose tape because it was the most reliable way to store digital data at the time in a portable device and I did not want to offer a solution that would look less reliable than film for image storage after capture.

Q: The images you took with the first camera where displayed on a TV screen (as the personal computer was not yet invented at the time) what was the reaction of people when they saw their images on the TV for the first time?

A: The most common reaction in the demonstrations of the system was people would move very close to the TV screen to closely examine their image.聽 There were a number of image quality issues with the captured images such as inadequate bit depth per pixel (only 4 bits / pixel), visible sensor defects and lack of resolution (not to mention lack of color).聽 In spite of these shortcomings most of the people who witnessed the camera and playback system liked the demonstration. It simply and clearly demonstrated the concept of an all-electronic still imaging system that could be extrapolated to a future consumer product.聽 I learned here that nothing involves an audience (even in the corporate world) like personally involving them in the demonstration of a new system.聽 It is hard to be disinterested when your picture is up on the screen.

Q: What reactions did you get from other Kodak employees and managers at the time? after all Kodak was first and foremost a film company and your work was supposedly undermining the core business of Kodak…

A: I was in the R &D community and therefore surrounded by curious people who supported new ideas.聽 There were some that recognized, in spite of its primitive state, that this system could significantly impact Kodak鈥檚 business in the future. I remember one comment made to me by R & D manager who I happened to pass in the hallway on my way to another demonstration of the camera.聽 He said 鈥 I鈥檓 glad I鈥檓 not you鈥 referring to the expected reaction he thought I might get from the group of mangers he knew to be waiting in the conference room to see the system.聽 I must say I got lots of questions (many of which I couldn鈥檛 answer at the time) but was largely supported by my management and R & D community in general.

Q: How early did you realize the magnitude of your invention and when do you think other people start realizing it?

A: This project definitely impacted my career in that I was hooked on digital imaging and I ended up working exclusively in this area from the rest of my 35-year career at Kodak. I personally believed this approach to taking pictures would come to pass but I couldn鈥檛 predict when. There were many technical obstacles to overcome over the coming decades and I participated in some of these efforts over my career. 聽I must say, I was surprised by the interest in this original project all these years later. The reason the original prototype exists is that I personally kept it with me as reminder of this great project from which I learned so much. I never really thought much about the historical nature of the work. I think the company realized around 2004 or so that this milestone that took place at Kodak could help the company establish itself as the pioneer of digital photography and therefore started asking me to participate in a number of public relations / marketing events starting around then.

Q: At the time you estimated that it will take between 15-20 years for the camera to reach the market – you where right and the first digital camera models shipped in the early to mid 1990's, however the real digital camera revolution took another 10 years or so to happen – so do you feel that you got it right after all?

A: Any accuracy of my predictions about the timing of the switch to digital imaging for the consumer was largely luck. The 15 鈥 20 year prediction was based on Moore鈥檚 law and an assumption that 2 MP images would be starting point for consumer acceptance of image quality. Of course a number of factors that were critical to evolution of digital photography were happening at the same time (personal computers, desktop photographic printing, in camera display technology鈥.). The industry hit the 2 MP image point for cameras around 1999 聽(Kodak DC 280) which was around the time that the sale of Film cameras peaked along with film sales.聽 It was another 4 years or so until the number of digital camera sales exceeded the number of film camera sales (2003).聽 So I guess, depending upon when you want to say revolution started you could say the transformation took 22 years (1999 film peak) or 26 years (2003 digital camera sales).聽 Either way those durations looked like a long time away when I was demonstrating the original system in 1976.

Steven Sasson – in the mid 1970's the digital revolution looked far away (Credit: Steve Kelly/Kodak)

Q: What do you think made Kodak wait or at least not push forward much harder during the 1990's and early 2000's at the beginning of the digital revolution, giving the Japanese manufacturers the edge in digital camera production?

A: Kodak was caught in the position of being successful in the existing technology that had a well-proven business model.聽 The emerging technology of digital imaging had a very uncertain / unclear business proposition.聽 Kodak liked to sell materials, photographic materials at which it was good at manufacturing.聽 Trying to apply this to the emerging technology drove Kodak to hybrid solutions (photo CD) and new ways for customers to get prints (picture kiosk business).聽 These were good options for the company but many times the company lost its resolve on initiatives that it started (professional digital cameras, Imager production, many attempts at inkjet printing, online picture fulfillment). Cameras were often thought of as on ramps to other businesses with which Kodak could be more profitable (printing).聽 I expect there will be more written on this classic case of technology disruption of an established business so I 鈥榣l leave it there.

Q: Do you feel that your invention has at least some role in what is happening to Kodak today?

A: Sure, it represents a milestone of the start of a long story of technology substitution.聽 This revolution would have occurred without this project but it points out how long a time horizon business leaders must have when investing for the long term survival of any enterprise that depends on a particular technology for its existence.

Q: When you look at what is happening to Kodak, a company you worked for – for so many years, what does it make you feel?

A: I am very sad to see the company I worked for under these circumstances. They had the smartest people in imaging and were successful for over 100 years.聽 The digitization of information had affected many companies over the last 20 years and certainly includes Kodak. I wish them the best.

Q: Finally, what are you doing these days after you have retired from Kodak and is photography one of your hobbies?

A: After retiring in 2009 I did some consulting work for Kodak to help with the IP licensing efforts that underway when I left.聽 Now I am doing independent consulting on IP matters involving Digital imaging.聽 Yes, as you may suspect I have many digital cameras and try to use them in doing nature photography.聽 I do public speaking about the development of the digital camera as well and in the course of these events I get a chance to meet real photographers are very creative.聽 So I don鈥檛 admit to doing much photographic work around these professionals but I do like to take outdoor pictures when time permits.

In early 2011 photographer David Friedman had a short video interview with Steven Sasson (youcan find more interesting video interviews with inventors on Friedman's blog)


讟注谉 注讜讚 讻转讘讜转 拽砖讜专讜转
讟注谉 注讜讚 讘 English

讻转讬讘转 转讙讜讘讛

讛讗讬诪讬讬诇 诇讗 讬讜爪讙 讘讗转专. 砖讚讜转 讛讞讜讘讛 诪住讜诪谞讬诐 *