Photography for Reproduction

Photography for reproduction by Dr. Chris Lantz Many publishers have routinely relied on digital imaging for low resolution applications in newspaper production and desktop publishing for just over a decade. Cameras that capture just beyond television resolution images (640×480 pixels) are adequate for some of these applications and typically cost $300–$1,000 today. Low- resolution digital cameras are well suited to web sites, computer presentations, and output to laser printers because their resolution capacity matches the typical output resolution of low-cost monitors and printers. Higher resolution megapixel cameras have recently been introduced at slightly under $1,000 for the first time. These new low-cost cameras complement the increasingly common 1152×780 computer display resolution and desktop printer resolu- tions above 600 dots per inch (dpi). The future widespread adop- tion of the Federal Communications Commission approved HDTV (High Definition TeleVision) standard will likely spark a new round of low cost digital cameras to fill an even higher resolution standard in the near future. At the upper end of the digital camera market, commercial publishers have used high resolution digital cameras for catalogs and periodicals which depend on the rapid production of hundreds of images per issue. Currently, there are high resolution cameras in the $10,000–$20,000 price range that can approximate the resolution of ISO 400 speed 35mm transparency film. There are also cameras in the higher $25,000– $50,000 price range that can approach the resolution of conventional films such as ISO 25 speed 35mm transparency film. Some imaging technologies can now exceed the resolution of large format 4×5 or 8×10 inch film, but these currently are only cost effective for applications such as remote imaging via satellites. Visual Communications Journal 1999 Page 19 Even though the quality of images that can be produced by digital cameras has increased dramatically in the past few years, they may not be appropri- ate for many uses. In this paper, the author compares the characteristics of film-based cameras to the characteristics of digital cameras and makes recommenda- Figure 1: Bellows (left) and extension tubes (right) provide cameras an tions regarding the use of each ability to image objects larger than life size on film. The greater the dis- type of camera in today’s market. tance between lens and camera the closer focusing distances are possible. Camera controls: digital versus analog ping capability are essential cre- natural light, electronic flash ative tools of the professional lighting is unnatural by virtue of A disadvantage to many of the photographer. its angle and the high contrast of low- to mid-priced digital cam- Another drawback of the low- the shadows it casts. There are eras on the market is they rarely cost digital cameras is that they some techniques that can be used have the manual exposure and do not have a removable lens to soften flash lighting, such as focusing controls on which pro- mount. Hundreds of convention- bouncing it off a white card, but fessional photographers depend. al 35mm SLR camera lenses and the small built-in flash lamps Some high-end digital cameras accessories are available. Without available on digital cameras lack in the $8,000-$25,000 price access to special lenses, photo- both the power and angle adjust- range are actually film-based graphers cannot use low-cost ments to make such techniques cameras that are converted to cameras to control the angle of possible (Figure 2). digital-based cameras by replac- view and perspective of objects in Most of the lowest-cost digital ing the film back with a digital the scene. In addition, close-up cameras have fixed-focus or sensor back. These converted or macro photography is not an focus-free lenses. Fixed-focus cameras are equipped with the option when using many low- means that the lens was fixed at manual controls of the standard cost cameras, because special one focus point at the factory and 35mm camera from which they equipment, such as extension that any subject closer or further were created. tubes and bellows, is not available away from this point will be out In the $500–$3,000 price (Figure 1). of focus (Figure 3). The focus range, digital cameras do not Other big disadvantages of the point is in the middle of the lens have the depth of field control lenses on low-cost digital cam- focus range. This provides a rea- afforded by f-stops, nor the eras are their relatively low qual- sonable chance of getting a sharp motion-stopping control provid- ity and less-than-optimal light picture, but the drawbacks of ed by a manual shutter speed. gathering ability. High-speed fixed focus are very apparent These are major limitations that lenses transmit more light when with close up photography. prevent many professional pho- needed in low lighting situations. Better digital cameras have tographers from switching to the Digital camera lenses are often true auto focus mechanisms digital format. Control over quite slow, so harsh flash lighting which ensure sharp focus on sub- depth-of-field and motion stop- is necessary. When compared to jects at various distances from Page 20 Photography for reproduction ride. Manual exposure allows photographers to produce a dark or light picture on purpose or as a special effect. Even if the photographer is shooting a dark or light subject, the exposure system in an automatic camera is pro- grammed to produce an 18% gray average density. If manual exposure controls were provided, the photographer could overex- pose to compensate for a light Figure 2: The flash built into digital cameras are not adequate in power nor subject or underexpose for a dark have the angle adjustments to allow softer more natural reflected light as is subject. provided in the bounce flash setup on the right. Despite the disadvantages of low-cost cameras, they still have the camera, so long as the subject the subject is dimmer or brighter many important advantages. A is in the center of the viewfinder. than the background or if the 640×480 image can be accept- Autofocus systems have a sensor subject is not centered in the able, even in high-resolution that measures the distance to the viewfinder. Multi-cell metering magazine publishing, if it is used subject and then changes the collects light readings from vari- at a fraction of its original size. focus of the lens elements to ous positions in the viewfinder Many lower-cost cameras are just compensate for different dis- and averages the readings. Multi- starting to incorporate exposure tances. Although this is much cell metering compensates for value (EV) adjustments, which better than fixed focus, it still back-lit scenes that would turn photographers can use to adjust causes problems if the photogra- out as silhouettes without this to prevailing lighting conditions pher wishes to place the subject feature. using a built-in LCD preview of the photograph off-center. Finally, most entry-level cam- screen (Figure 4). As digital pho- One approach to solve this prob- eras lack a manual exposure over- tography rapidly becomes more lem is to use multiple focus sen- sors across the field of view and not just in the center. This improved focus system is available in conventional cameras but not for low-cost digital cameras. Low-cost digital cameras often lack light metering features such as multi-cell metering and backlight control. In addition to calculating the focus from the center of the viewfinder, many cameras measure the amount of Figure 3: The Quickcam is an example of a fixed focus digital camera (left). light in the scene from the center It is possible to change the fixed focus point but the camera needs to be disas- only. This can cause problems if sembled in order to accomplish this, as is demonstrated on the right. Visual Communications Journal 1999 Page 21 Figure 4: This digital camera has the ability to capture images on standard floppy disks (left). It also has a three inch LCD viewing screen. This screen is used as a viewfinder, to preview images, and also make exposure adjustments with a built-in EV exposure value control (right). mainstream, many of the features Basic image structure: will be much less expensive in the that are presently lacking in low- digital versus analog future. However, even the most cost cameras will be included. optimistic do not predict that When this happens, many more In spite of these rapid devel- digital imaging systems will be applications will be opened up to opments, digital imaging tech- able to financially compete with digital imaging. nology has not overtaken tradi- most film-based systems in the As recently as 1996, only a few tional photography as the stan- short term. Even if revolutionary low-cost digital cameras were dard format for many commer- imaging systems were developed available. By 1998, there were cial publishing applications. This in the short term, problems, such over 50 models. One new type of is mainly due to the fact that as projection and display of digital camera is the Digital conventional photographs are images, will still exist. Computer Video Cassette (DVC) camera very high in resolution and low projection, LCD, and flat plasma that can be used to capture both in cost. Kodachrome color slide panels are great recent strides still pictures and video (Figure film, invented in 1937, currently that have been made in digital 5). DVC cameras have a new costs under $10 per roll, and, image display. However, these Firewire computer interface.

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