The Evolution of Digital Cameras

It was getting close to 8 P.M. on this fall evening as I was occupied with family portraits in a Lutheran church in Evansville. I had posed a family of five as I approached the camera only to have the youngest child getting anxious. Yet, before I could step in to work with the child, Andrea had approached to lend some assistance.

Now Andrea was an attractive, svelte young woman who was involved in church activities, and opted to stay during the photo sessions, if not to be helpful, then to pick on me.

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Andrea had approached the child and made certain that the clothes were straight and kept the child occupied while I readied the camera. While she was bent over, tending to the child, she shouted to me, “Now don’t you take a picture of my butt.”

While my attention had in no way been directed to the subject of her inference… ahem… I could not resist saying back to her, “Not to worry, I don’t have a wide-angle lens.”

Although the thought of dodging the object which Andrea threw in my general direction had momentarily entertained me, it seemed impractical with the degree by which she had missed. I do, however, believe that the person I heard screaming from behind me had wished they had entertained such a notion.

As about ten minutes had passed allowing completion of the portrait session, I was readying for the next subject while keeping a watchful eye on Andrea, as she was standing behind me.

The next subject was an older couple, Bub and his wife. I had set them into place and resumed my position at the camera as I congratulated Bub on his fine performance by not crying. I framed the shot when Bub had said, “Women want me”, of course at my prodding.

This statement had produced the intended expression as I triggered the shutter. The shutter made its distinct sound, the film advanced, yet I had a blank video screen. On a subsequent shot, it was the same result, a blank video screen.

It was then that I looked at Bub and said, “Finally, I have met the person who can break this camera.”

A Camera and a Sled?

The camera I had used in the proceeding story was a CamerZ 70mm rollfilm camera. It would be attached to a device called a sled which permitted me to capture a film and digital image simultaneously. This was accomplished with the use of a beam splitter, a glass surface which transmits 50% of light while reflecting the other 50%, mounted on the front of the sled which permitted the film camera to take an exposure, at one stop light loss, while the digital camera was mounted on the bottom front using the reflected image to capture a digital image. This had the ability of allowing us to show the images before the film was developed, for the purpose of taking print orders.

It is interesting that this process seems commonplace today, yet the year in which I was using this equipment was 1994. The sled and digital camera were leased from Kodak.

What happened with Bub’s session did not actually have anything to do with the digital camera itself, although the sled was still replaced for cautionary reasons, but it was a short in the cable which connected the camera to the computer. This still did not prevent the minister, Brother Glen, from having fun by posting a warning on the bulletin board at the church stating that Bub’s face could be detrimental to a camera.

Early Still Video

It was in 1972 when Texas Instruments had patented a prototype still video camera. It however would not be until 1981 when Sony would introduce a commercially viable still video camera called the Mavica.

Still video was not digital as it still used analog technology. Analog technology used electronic impulses to produce a result in its receiver. In the case of video, or television, this data would be applied to a carrier, a radio wave, to deliver the data to a receiver. In the case of a still image, it could be saved to a media, usually magnetically, to be viewed on a monitor at another time.

The media to which analog video could be saved was often in the form of magnetic tape, although for still video, there were forms of magnetic media used with the camera which were similar to floppies.

Still video did not offer that great of resolution as its intended purpose was to be shown on a television set. A television set has an image that is measured in lines of resolution. Although the resolution for NTSC television standards is listed as 525 lines of horizontal resolution, this number is misleading as it includes odd and even scan lines and lines of synchronization.

The picture on a North American television set is comprised of 29.97 frames per second. Each frame is scanned twice consisting of a scan of 240 lines odd and 22 black lines, then 240 lines even, then 23 black lines (the black lines are for synchronization purposes). For the purpose of our resolution, we will count 480 lines which gives us a VGA image (640×480). Still video cameras come in around 220 lines, which would put them about 440 lines of resolution for the purpose of our count, which gives us a roughly 580×440 image, although that varies depending on the camera.

*Please note that this has been an over simplified version of NTSC standards for the purpose of comparison to digital equivalents.

Clean up your act!

It is interesting that digital video was developed in the 1960’s by NASA, well before the still video cameras were developed using analog technology. Digital video was developed for the space program as radio waves carrying an analog signal were too lossy to deliver a useful image from a space probe or satellite mounted camera. Digital technology, however, made it possible to do such.

Unlike analog technology, which uses electrical impulses, digital technology used binary, 0s and 1s, code. Unlike analog data, digital data does not degrade as the carrier degrades. This allows for the receiver to receive a complete data package, regardless of the signal strength. Being that the data is also encoded in binary, this allows more data to be transmitted or compressed.

An overly simple and highly unrealistic illustration of analog versus digital would be to use a stream to represent the carrier. If I were to place one large, yet fragile, picture in the stream, representing analog data, and someone was waiting downstream to receive the picture, the chance that it would make it to them complete lessens with the further they are down the stream. If I were to place several smaller, sturdier pictures in the stream, representing digital, they are much more likely to receive a complete picture.

Since digital technology uses much less space than analog technology, it makes sense to use digital for images. The basic technology for capturing an image to digital or analog, however, does not differ much.

Where have we been?

Although there can be discrepancies in the history of events, as with any subject, I will cover noted events in the development of the digital camera over a nearly 30 year span. You can add your own remarks as you see fit.

Kodak, interestingly enough, was the chief pioneer in the field of developing digital cameras. They had been developing sensors for converting light to digital since the mid 1970s. It was in 1986 when Kodak scientists took a big step with the development of a 1.4 megapixel sensor. They followed up in 1987 by releasing several products for manipulating, storing, and printing still video images. And in 1990, Kodak introduced the Photo CD system. It was almost as though they were saying to Polaroid, “Na-na-nah-na-na.”

In 1991, Kodak released the first professional digital camera system, creatively called DCS (heh… heh), by taking a Nikon F3 camera and fitting it with a 1.3 megapixel sensor (anybody else think that was a perfectly good waste of a Nikon). This was aimed at professional photojournalists as 1.3 megapixels provided a decent image for print in a paper, but nothing to compete with film. Kodak also took this technology and incorporated it into a system to be used by professional studios to allow them to capture a digital image simultaneously with a film image. This was the same device as I mentioned at the beginning of the article; a DCS sled (sled was a common nickname and not the actual device name).

As this equipment was very expensive, it was relegated to industrial uses and not the consumer market. However, companies would follow suit and introduce a consumer level digital camera. Although the Dycam Model 1 (Logitech FotoMan) would be introduced in 1990, it was a black and white digital camera offering a 376×240 image. It would not be until 1994 that color digital cameras for consumers would be offered by Apple (Quick Take 100) and Olympus (Deltis VC-1100) offering VGA (640×480) resolution. Kodak and Ricoh would follow in 1995 with their own consumer models ushering in the beginning of digital photography as we know it.

How do digital cameras work?

Q: What is a clear sign of stupidity?

A: Asking how digital cameras work and then trying to give a simple answer.

In the most basic terms, a digital camera is a film camera which uses a sensor in place of film. This sensor is a silicon chip of one of two types: a CCD (charge-coupled device) and CMOS (complimentary metal oxide). The CCD chip, however, is more commonly used.

The surface of the sensor contains light sensitive spots called photosites, basically microscopic photocells - this array of the photosites number into the millions. These photosites take light and convert it into photo electrons, which are still in analog form at this point until the processor interpolates the information on each pixel into RGB values based on their adjacencies to each other.

Although this is a generalization, there are variances among different models of cameras and some manufacturers hold to their processes as secretly as film manufacturers held to theirs. It is probably just a lot easier to refer to digital camera sensors as electronic film as the function they are trying to perform is the same.

I hope that my momentary lapse of sanity did not distract too much.

Oui madame. Do you like it in Digital or in Film?

One of the reasons I started this article was to do a comparison of film versus digital. I downloaded and referenced several articles which were written probably over a span of two years. This would seem to give me a better foothold for writing on such a subject, right? Uh, not exactly. Although I do now have some better figures to share, I have found a cure for both insomnia and lucidity.

In comparing digital images from some of the latest models of digital cameras, especially digital SLRs, it would seem that a frame of 100 speed 35mm film which has an equivalent value of an 11-15 megapixel image would hands down beat an 8 megapixel image from a digital camera, but size is not all that matters (what is that strange sound like a bunch of grown men crying).

Getting into the variances of the different models of digital cameras would take several of these articles and more stamina than I could possibly muster. Staying with the current crop of digital cameras (this article is being written in April of 2005) gives us cameras capable of almost noise (digital equivalent of film grain, sort of) free image capture. This is important as the digital image, although it may be smaller in quantity to the film image, offers a cleaner image compared to the film image when grain is noticeable. This means an 8 megapixel digital camera can provide an image quality equal too or even better than many 35mm films, especially those at higher speeds than an ISO 100, and several 6 megapixel cameras offer favorable comparisons.

Comparing the digital image to a slower speed film or a larger negative film brings down the digital image in comparison, but that is really being unfair ain’t it.

I do not have a complete chart for all film equivalencies in megapixels, but I will provide equivalencies for ISO 100 speed slide film in different formats.

A 100 speed 35mm slide = 11 megapixels
A 100 speed 6×4.5 slide = 31 megapixels
A 100 speed 6×6 slide = 42 megapixels
A 100 speed 6×9 slide = 62 megapixels

As you can see from the comparisons, the larger film stock, and I have not even covered 4×5 and 8×10 sheet film, gives a much more desirable image for large prints. Other than for large prints (say 16×20), the digital cameras do offer high quality images which will satisfy and exceed many needs. Plus they are a lot more convenient for computer enhancement purposes.

For myself, I still love and need my film. They will have to pry it from my cold dead hands before I stop using film (I heard that, stop making plans).

*Film does have better color and visual information detection than digital, but it depends on your subject matter if this difference is important to you or not, as for most situations digital provides plenty of detection. The comparison chart is based on slide films which has fewer levels of exposure compared to negative film. Slide film has about five levels of exposure as compared to print film which can have nine or more levels thus providing greater perceived depth and the ability to capture more color and tonal range. This is represented by exposure latitude which is very specific in slide film (about ½ a stop, maybe even 1 stop over) but wide in print films (1-2 stops under, 2-3 over). Exposure latitude is the films ability to be under or over exposed and still delivers a good exposure. As you can see, print film can be properly exposed and still deliver up to 5 more stops of good exposure in an image providing greater depth than slide film.

Another Photo Op.

I was doing portraits at another church several weeks later when Bub appeared with his daughter, Babs, to have her portrait done as she was not available at the time I did Bub’s portrait.

I had set up the pose with Babs, a very polite young lady, and moved to the camera to take the shot. When I had tripped the shutter, an alarm went off on the camera. Babs was looking concerned as Bub was trying to look anywhere but at me as I said, “My goodness, it’s genetic.”

I was being facetious as it was an alarm informing me to change film.

Note: Bub and Babs are substitute names as I do not remember their actual names. All other names have not been changed to protect the guilty… uhh… I mean innocent.