Camera Basics

Digital Cameras - A beginner's guide. Pixels. Aspect Ratio Sensor Size White Balance Sensitivity Digital Zoom and Optical Zoom JPEG, TIFF and RAW Display, Printing, DPI and PPI Digital Camera Interface Digital Zoom vs Optical Zoom There are two types of zoom on a video camera — digital zoom and optical zoom. A camera can have either or both types. The two different types are very different and the unwary buyer can get caught out badly by not understanding how they work. Digital Zoom This is often trumpeted as a big selling point by manufacturers. It's common to see a large "150X" emblazoned on the side of a camcorder. Video stores are full of naive customers comparing the digital zoom of different cameras. Do not be fooled! Digital zoom is all but irrelevant. It only exists as a marketing ploy to trap unsuspecting newbies. Ignore this spec completely, and if a salesperson tries to impress you with it, find another salesperson. Digital zoom works by magnifying a part of the captured image using digital manipulation. This is the same as how a graphics program resizes an image to a larger size. The process involves taking a certain number of pixels and creating a larger image, but because the new image is based on the same number of pixels, the image loses quality. At small zooms (up to 20x) the loss may not be too noticeable. At large zooms (up to 100x or more) the quality becomes absolutely terrible. Some digital zooms use interpolation, which is a way of estimating the value of the new pixels rather than simply duplicating existing pixels. In theory this should reduce the loss of quality, but no amount of interpolation will prevent loss altogether. Remember that digital zoom can be done in post-production with any half-decent editing software, so you really gain nothing by having the camera do it. Optical Zoom This is the zoom spec which matters. Optical zoom is provided by the lens (i.e. the optics) and does not lose image quality. The zoom is provided by a telephoto lens. Most consumer camcorders come with optical zooms of between 10x and 20x. 10x is adequate for most applications. More is usually better — 20x should be ample for all but the most demanding zoom users. Factors to Consider when Choosing a Digital SLR Camera The newcomer to the world of Digital SLR cameras is presented with a bewildering array of options. It’s hard to keep track of exactly who is currently making DSLRs and how many models each have, but as of summer 2008 there were at least 9 manufacturers (Canon, Fuji, Leica, Nikon, Olympus, Panasonic, Pentax, Samsung and Sony) and between them there were something like 34 different models. How do you choose which one to buy, and in what ways are they different? With so many different cameras available and new models being announced every few months it’s not really possible to make specific recommendations on which one is "best". The term "best" will depend on many factors unique to the user. However, I will attempt to outline the various factors that you might want to take into account when deciding which one to purchase. Contents 1. Compatibility with Existing Lenses 2. System Expandibility 3. Price 4. Format Size 5. Image Stabilization 6. Size and Weight 7. Pixel Count 8. ISO Settings 9. Noise Level 10. Metering 11. Autofocus 12. Continuous Capture Rate and Buffer Size 13. Live View Capability 14. Video Capability 15. Viewfinder Size 16. Flash System 17. Other Features 18. The Bottom Line