Learn the ropes of Digital Photography

Learn the ropes of Digital Photography
by David Peters
The camera has one small, slow chip and very little memory to do that interpolation. Your computer has a big, powerful processor and lots of memory, not to mention, no particular need to compromise their software routines to fit into a small amount of memory or trade quality for speed to avoid long delays after taking a picture. In short, your computer will do a vastly better job at interpolating the picture than your camera will, and to top that off you can choose different algorithms (often named after the mathematicians or programmers who created them, like Lanczos or Mitchell) and experiment with how well they work on a particular image. You can even save different versions of the file, including the original, which you can't if the camera is doing the work. There's nothing to be gained by compromising image quality, which is exactly what you're doing if you don't use the best filter you can get your hands on. The interpolated image even takes up more space on your camera's memory card, but it doesn't hold any more information than the original. Finally, as I mentioned above, it adds time between shots, as the camera has to grind away at reshaping your picture before you can take another one.
Exchangeable Image File (EXIF) data, saved by modern digital cameras in each picture file, is a powerful tool for both keeping track of your work and learning more about how to use your camera and how to take advantage of its capabilities. Created by the Japan Electronics and Information Technology Industries Association, this standard is now used by almost all digital cameras. EXIF data stores, as part of the picture file, information such as the date, time, camera model, and settings such as focus mode, flash mode, ISO sensitivity setting, white balance, and many more facts about the state of the camera when the picture was taken. The EXIF data actually envelops the picture data, be it compressed (usually JPEG format) or uncompressed (RAW or TIFF format) data. The data does add anywhere from 100 bytes to 64 kilobytes to the size of the file, but it is invaluable for anything from keeping track of work, indexing large numbers of photographs, or learning more about how your camera's settings affect the quality of the final product.
What is it that is actually capturing the image? Where film cameras have a roll of film exposed behind the aperture, digital cameras have a sensor. Most digital cameras use an array of photo sensors under a filter matrix which results in the sensors each recording red (8-12 bit), green (8-12 bit) or blue (8-12 bit) light intensities. These separate sensors or channels create what is often referred to as the Bayer matrix pattern where every other sensor records green with the alternating cells recording in red or blue. Each pixel in a conventional sensor only captures one color. This data is typically 10 or 12 bits per pixel, with 12 bits per pixel currently being most common. Most cameras now provide the option to instantaneously store the captured material in a RAW file while alternatively the camera's processor can weave the RAW data using all three color channels to provide an instant 24 bit full-color JPEG or TIFF display image. RAW is not an abbreviation but literally means "raw" or "unprocessed". A RAW data file contains the original image information as it comes off the sensor before in-camera processing so you have a variety of choices in processing the data on your PC using one of many editing software programs available.
When discussing image quality for digital photographs image noise is the equivalent of film grain for analogue cameras. Despite the fact that we are working in a visual instead of an audio medium, it is called noise, which is analogous to the subtle background hiss when a television channel has no broadcast or your audio system is turned up at full volume without a record or disk. In digital images, noise refers to random specks on the surface of a photo, which can degrade the quality of the image. While noise is often seen as a distraction and detriment to a photograph, it can be a desirable condition for certain artistic effects. Noise varies with sensitivity settings, length of exposure, temperature, and different camera models. The signal to noise ratio (SNR) is a useful and universal way of comparing the relative amounts of signal and noise for any electronic system. ISO setting or ISO speed are the standards, which describe a camera's sensitivity to light. A camera's relative sensitivity to light is represented by the ratio of the two ISO numbers. In terms of practical application, a photo taken at ISO 200 will take half as long to reach the same level of exposure as a photo taken at ISO 100 where all other settings are the same.
For the photographer that has a tight budget, it's good to know that there are free resources out there! If you take digital photos, then you can use some great editing software that is absolutely free, made available by Windows. Editing your pictures is a very important step in the photographic process, and can end up costing a pretty good amount of money by the time you are done. Anyone that needs to save money can take advantage of some great editing programs that are free and easy to use! Almost all digital cameras purchased today have a photo editing software program that comes as part of the purchase. These can provide simple cropping and picture modification. One of the many free photo editors offered by Windows is Paint.net. It is offered by Washington State University. You can freely download this freeware and use it to edit your own digital photos. The software has a ton of really cool features, including special effects! It is easy to use and you can even log onto a user forum, if you should need any help or want to see how others are using this great freeware! Another user-friendly freeware program that you can download to edit your photos is VCW VicMan's Photo Editor. This freeware is similar to Adobe's Photoshop. This software has a limited free version, but you can purchase the software for a great price. If you take a little time, you can find it offered at many online merchant websites and can even stumble across some great discounts!
Most experts will tell you what the automatic flash built into many digital cameras can't do - change light angle, redirect off surfaces to soften the effect but what is such a flash good at? As it turns out, there are a few times when such a feature is quite handy. While it can be handy to have dedicated lighting, or even a slave flash unit linked to your camera, there are good reasons why such items do not come standard with most cameras. Fill flash (also known as "forced on" or "anytime" flash) is a feature found on most digital cameras that allows the user to trigger the built-in flash whenever a picture is taken - no matter the light level. This is handy when natural light is behind the subject, but also to fill in shadows anywhere in the frame. While your eye can see the detail in these shaded areas, often the camera cannot. Many outdoor pictures are spoiled by excessive shadow or loss of detail when natural light seems adequate to the eye.
Memory Sticks are used only in Sony products, and Sony is serious about keeping the technology in use. Unfortunately it seems like no one else is. They're available up to 4 Gigabytes in capacity, have good speed, but if you're using a Memory stick, it's probably because you're using a Sony camera and you don't have a choice. The newest common storage media are xD-Picture cards. Developed by Olympus and Fuji as a replacement for the older Smart Media cards, xD cards are compact and durable, with a heftier shell than older designs. They are stable in the market and likely to be around for a while, but they are gaining neither market share nor size rapidly - currently the largest xD cards are 1 Gigabyte. This is probably because only Olympus and Fuji now use this standard. Wide and wafer-thin, Smart Media cards define "legacy technology." Available only as large as 128 Megabytes, this is one technology I would have expected to have been "voted off the island" by now. Alas, they were used in tens if not hundreds of millions of cameras and smart phones, so they are still being made and will be available for some time. You won't find them in any new cameras, however.