Digital Library Volume 4 F A Q FREQUENTLY ASKED QUESTIONS on DIGITAL PHOTOGRAPHY EN Frequently Asked Questions on Digital Photography Digital Library Vol. 4 Disclaimer: While every endeavour has been made to provide accurate information, no liability will be assumed for typographical errors and omissions or technical inaccuracies. 1 Contents 1. The fascinating world of digital photography 4 2. Digital camera technology 8 2.1 How does a digital camera work? 8 2.2 The CCD chip 9 2.3 What to look for when buying a digital camera 13 2.4 Factors affecting image quality 16 2.5 The importance of a good lens system 18 2.6 Long-term storage of digital images 20 2.7 Servicing digital cameras 21 2.8 Power sources 22 3. Taking digital pictures 24 3.1 Metering systems 24 3.1.1 Exposure metering systems 24 3.1.2 Focus systems 27 3.1.3 White balance 28 3.1.4 Sensitivity 31 3.2 The camera flash 32 3.3 Image optimisation systems 34 3.3.1 TruePic 34 3.3.2 Noise reduction 35 3.3.3 Pixel mapping 36 3.4 Scene programs 36 3.5 Manual control 37 3.5.1 Aperture 37 3.5.2 Shutter 38 3.6 Histogram 39 3.7 Zoom 39 3.8 Macro shooting 40 3.9 Sequence shooting 42 3.10 Self-timer 43 3.11 Panorama 43 3.12 B & W and sepia 45 2 EN 3.13 Blackboard/Whiteboard 46 3.14 Movie mode 46 3.15 Sound recording 47 3.16 General tips and hints for better photos 47 4. Printing digital images 50 4.1 Traditional photos vs. digital photo prints 50 4.2 Home printing 51 4.3 Printing services for digital photos 56 4.4 Enlarging digital prints 57 5. Archiving digital photos 60 5.1 Software solutions 60 5.2 Recommended hardware 62 5.3 Downloading images from memory cards 63 5.4 Connecting a digital camera to a computer system 64 5.5 Important image file formats 65 5.6 Copying images to a CD-ROM 68 6. Compressing image data 70 6.1 Storage requirements 70 6.2 The important compression methods 71 6.3 Selecting the right compression level 74 6.4 PKZIP/WinZIP and StuffIt 75 6.5 Pixel number in compression 76 6.6 Saving images in different file formats 76 7. Editing digital images 78 7.1 Image editing programs 78 7.2 Sending image files by email 79 7.3 Transferring digital data with a mobile phone 80 7.4 Digital images for the internet 81 7.5 Viewing digital pictures with the TV 83 8. The A to Z of digital photography 84 3 1. The fascinating world of digital photography “A picture says more than a thousand words.” This is certainly one explanation for why photo- graphy has lost none of its power to fascinate and enthral in its almost 200 year history. Even though the cameras were still expensive, heavy, cumbersome and complicated well into the 20th century, these failings proved to have little influence on the technology’s success. The reason: for the first time it was possible to capture moments in time and illustrate feelings, moods, desires at more or less the press of a button. Photography was here to stay. Whether digital or analogue, in the studio or out in the open, photography is always much more than just capturing reality. It is also the interpretation of what the photographer sees and the transformation of this into a new, two- dimensional reality so that the moment comes back to life when the image is viewed. It’s a pity then, that with conventional analogue photography the results cannot be seen immedi- ately, checked or edited until the film has been exposed and developed. While the instant photo technology introduced by Polaroid went some way to changing this, it was digital imaging that really revolutionised the photographic experience. Initially, this new technology was prohibitively expensive and really only attractive to technologi- cally adventurous pro users. However, as a result of the internet and email boom, demand for easy- to-produce and affordable digital images rose to unforeseen levels. This, together with the ever 4 EN lower cost of components (LC-Displays, CCD chips, etc.), led to the first affordable, digital cameras appearing on the consumer market in the mid 90s. Similar to the development of the computer, digital photography has experienced a dramatic increase in performance power. For example, whereas the first consumer camera had a resolution of only around 300,000 pixels, today there are models with five million pixels or more that not only meet the needs of professional photographers but also fit the price range of amateurs. 5 1. The fascinating world of digital photography The growth in the number of manually adjustable shooting parameters is equally impressive. While the earliest models featured as good as no individually adjustable settings, modern digital cameras are on a par with their analogue counter- parts when it comes to manual control. The reasons for the appeal of this imaging tech- nology are manifold. These are just ten examples: 1. No need to buy film ever again. 2. Storage media is reusable. 3. Images can be checked and enjoyed immediately after capture. 4. The cameras’ optical systems are of the highest quality and have a superior lens resolution compared to those in analogue models. 5. Silent operation for discrete shooting. 6. Creative effects possible even at the recording stage. 7. Presentation of the images on a TV (slide show). 8. No loss of quality when copying and transferring data. 9. Editing images later is easy. 10. Prints can be produced and photos sent via email immediately. 6 EN So, it’s hardly surprising that the digital camera market has been enjoying such an extraordinary growth rate. While the total of digital cameras sold in 1996 reached just about 1.2 million (of which only 100,000 were sold in Europe), this number had risen to 18.5 million worldwide in 2001. However, since a large proportion of digital camera users are new to the technology (and not always familiar with the workings of PCs), and because of the rapid development in this field, new questions constantly arise and older ones go unanswered. In this booklet we have therefore tried to present short, to-the-point answers to frequently asked questions. Naturally, this brochure will not be able to cover all aspects of this complex subject. We would though be delighted if the FAQ could help you get more enjoyment from digital photography and even obtain better results. 7 2. Digital camera technology 2.1 How does a digital camera work? Digital cameras cannot be so readily compared to analogue cameras, which use slide or negative film. Seen from a technological point of view, they are more similar to video cameras that take one image at a time. First, let’s look at how an analogue camera works. The analogue camera Simply put, it consists of a lens system, an aperture and a shutter. The lens system ensures the captured image is in focus while the ¡aperture and ¡shutter control the amount of light reaching the film. As soon as the shutter is released, light is let into the camera through the ¡lens system and aperture to land on the photosensitive film. The resulting chemical reaction records the image on the film surface. This image is then set in the developing process. Although digital cameras may often look like their The digital camera analogue counterparts and share many components, such as aperture, shut- ter and a lens system, their methods for recording images differ radically. Instead of light-sensitive film, they use a combination of ¡CCD chip, ¡imaging processing engine and storage media to capture the image. 8 EN The heart of the digital camera is hidden behind the aperture. The CCD (Charge-Coupled Device) chip is a light-sensitive semiconductor element made up of many silicon diodes. When light hits the individual photosensitive diode, it causes it to generate an electrical impulse which is read by the camera. The ¡analogue-digital conversion process converts the analogue impulses for each image dot into digital values for brightness. Those digital values are then calculated by the camera's imaging pro- cessing engine, comprising an ¡ASIC chip and software, to make better images (for example, by optimising gamma conversion and color repro- duction). The reconstructed digital image is then transferred into the camera's storage media. 2.2 What is a CCD chip? ¡Pixel: Abbreviation for “picture element”. It is the smallest element of a raster display or digital picture, containing infor- mation about brightness and color. Generally, The CCD chip is about as large as your fingernail in a monitor or and has millions of photosensitive diodes ink-jet printer, a arranged in columns and rows on its surface, pixel can consist of up to 256 dots much like the dots, or pixels, on a computer per color. monitor. Exception: ¡Dye Sublimation. 9 2. Digital camera technology If each of the sensors on a CCD chip were to react to incoming light in the same way, a digital camera could only take black and white pictures. However, to ensure that all colors can be captured, the sensors are covered with different color filters – either RGB (Red, Green, Blue) or CMY (Cyan, Magenta, Yellow) with additional green filters for more true-to-life results. Besides color, brightness data is also required for correct image reproduction. The light for each of the three colors is divided up into 256 levels of intensity.