Wednesday, May 23, 2007
Camera Systems In The Digital Age
Today as camera manufacturers control all aspects of image capture and processing, it's time to reexamine what it means to buy into a system
In the photo press, the “designed for digital” discussion has tended to focus on lens design from the perspective of correcting for issues that are unique to digital sensors. For instance, image sensors, and the filters in front of image sensors, have a tendency to reflect some light back to the lens. To counter this, new coatings have been developed for the filters and the rear lens elements. This kind of innovation is certainly significant, but to think that “designed for digital” ends with new multi-coatings only hints at the real potential of a digital system.
With film, the user and the camera manufacturer were both taken out of the loop of one of the most critical aspects of making the image—the film and processing. In a digital system, the camera manufacturer is responsible for cameras, lenses and accessories, in addition to the image sensor and the various processing aspects that are built into the camera. Essentially, the camera makers now make the “film” and perform the role of processing lab as well.
When film was king and camera manufacturers started to advocate the notion of buying into a system, the rationale was that the photographer would want to buy into a complete solution of body, lens and flash that would all work well together. You'd buy XYZ's camera because you liked the XYZ lens mount and AF system, and you knew the XYZ flash units would work predictably with the camera. Each manufacturer emphasized the particular strengths of its system as leverage for the rest of the system. For example, you might not have been a huge fan of the Canon EOS T50 as a camera body, but you liked EOS autofocus, so you bought into the Canon EOS system as a whole.
The Art Of Compromise
Digital has changed the fundamental premise behind buying into a system. Today, buying into a system is about taking control over the entire chain of making the image. I'm fond of saying that everything in photography is a trade-off. You want a faster shutter speed; you trade depth of field. You want to shoot in low light; you trade a low ISO and therefore incur more noise. The trade-offs extend to the design and manufacture of photo gear as well. In lens design, optical engineers play a constant game of enhancing one aspect of a design at the expense of another. For example, a fast, sharp, apochromatic lens will be relatively cumbersome, heavy and expensive. If you want a lighter lens, you have to tolerate a certain amount of aberration. Although technology allows the engineers to minimize the sacrifices they have to make, there's no way to eliminate them altogether.
So if we accept that the engineering of lenses, cameras and internal circuitry all involves some degree of compromise, the strength of a digital system lies in the manufacturers' ability to mitigate the compromises through integration of the components. For example, suppose XYZ has been making cameras for 40 years. Its research and development includes work on glass formulation, coatings, barrel design, shutter mechanics…the list is long. Over the years, each time XYZ introduced a new product, it had hard data on the product's strengths and weaknesses. Of course, the company worked to maximize the strengths and minimize the weaknesses, but weaknesses still existed. Maybe a particular lens design demonstrated a slight falloff in off-axis light transmission at smaller ƒ-stops or maybe there was a slight color shift with another lens, etc. All of these minor flaws would have been known or become known over time.
Armed with reams of accumulated data pertaining to all of the gear XYZ produces, a new corps of XYZ engineers can plan how to virtually eliminate all of the compromises, however minor, inherent in the various gear. Referring to lens designers, camera designers and sensor designers, Chuck Westfall of Canon says, “The camera research and development group at Canon works very closely with the sensor development team to produce products that reduce or eliminate potential image degradation.”
Taken a step further, we can envision in-camera software, new algorithms and proprietary RAW converters that even more completely integrate the system. Lindsay Silverman of Nikon describes how Nikon is integrating the full system: “Nikon designs its lenses, camera bodies and software packages to work together as extensions of one digital imaging system. For instance, each AF Nikkor lens incorporates an on-board CPU that constantly records information for each specific image. That data is a great tool for the photographer as it can then be read and applied once the image is brought into the software environment. Once in Nikon Capture, photographers are offered a wide variety of editing tools, including Vignette Control and Chromatic Aberration Control, which can address and correct perceived issues within specific NEF (RAW) images.”