Digital Zoom
Digital Zoom
 |
CDN DTQ450X ProAccurate Quick-Read Thermometer
List Price:  |
DescriptionNSF approved. 6-8 second response. Water proof and shatter proof. Data-hold. Big digit. Food-safe abs plastic. Recalibratable. On/off button. Temperature guide on sheath. Sheath can be used as handle extension... |
Optical Or Digital Zoom? the Choice is Clear
What is zoom?
Sometimes when you take a photo you need to focus on one area in the picture frame. For example when you take a portrait photo you want to make sure the object's face fills the photo frame while when you take a group photo you want to make sure everybody is in the photo frame.
In to focus on that one area in the photo frame you can either physically move closer to the objects or use the camera's zoom feature. When using the zoom feature the camera (mechanically when applying an optical zoon or electronically when applying a digital zoom) enlarges that area to fit the full picture frame.
There are two types of zoom - optical and digital (in older film cameras the only zoom option was optical). We will try to explain the differences between the two.
How does optical zoon work?
Optical zoom works by physically moving the camera's lenses and changing the focal length. By changing the focal length you can make objects appear bigger and fit the full photo frame.
When satisfied with the zoom position you can shoot the photo by simply applying the shutter button.
How does digital zoom work?
With digital zoom you actually use built-in software in the camera to define a portion of the photo which you are interested in. Once chosen the software crops the rest of the photo and enlarges the area you chose to fit the complete photo frame.
The process of enlarging the zoomed area is also known as extrapolation. The camera software needs to calculate new values for the pixels that were cropped in order to result in a full frame photo. The downside of this digital process is that the enlarged photo quality is lower than the original photo taken.
It is easy to understand the quality loss using an example. Lets assume that you have a 2MP (2 megapixels) camera. You point the camera and decide that you want to zoom in 2X. You run the digital zoom software and choose a 2X zoom. To accomplish this zoom the camera crops half of the photo and enlarges the other half to create a 2X zoom effect. In the process a 1MP area is discarded (the half that is cropped). The other 1MP area is enlarged in a process that copies every pixel once to generate a 2MP photo. Although the new photo seems to include 2MP it really includes only 1MP of information that was copied once. The result is a photo with a quality equivalent to a 1MP photo.
If you have used a 4X digital zoom in this example the result would have been a photo with an equivalent quality of a 0.5MP camera (the zoom area is 1/4 of the frame - 3/4 of the frame would be discarded and the rest 1/4 would be copied three times to fill the frame).
Digital zoom significantly reduces the quality of the photo. If your camera does not include digital zoom you can always shoot the photo without zooming and then use a PC photo editing software to crop a portion of it and enlarge the rest. In fact using PC software is always the preferred method to built-in digital zoom since it allows you to try different zoom sizes, different zoom areas and different zoom algorithms while not losing the original photo.
So which one is better?
Optical zoom is superior to digital zoom. In fact from a practical point of view digital zoom should not be considered zoom at all. It is always better to apply digital zoom on a PC at a later time rather then when taking the photo using the camera's built-in digital zoom. When using a PC different sizes can be used and different zoom algorithms that can result in better qualities.
Know your camera's zoom
Some manufacturers claim the maximum zoom figure their cameras support without specifying if it is optical or digital zoom. This information is confusing as many consumers do not understand the difference between the two. For example if a camera supports a 5X optical zoom and 10X digital zoom advertising the camera as a "10X zoom camera" is confusing - 10X digital zoom can be done with any camera using simple PC software.
When buying a camera always make sure that you know what the optical zoom figure is and that it meets your needs. Ignore the digital zoom figure as it does not mean much and can not compensate for a camera with poor optical zoom.
About the Author
Ziv Haparnas is a technology veteran and writes about practical technology and science issues. This article can be reprinted and used as long as the resource box including the backlink is included. You can find more information digital photo printing printing and photography in general on printrates.com – a site dedicated to photo printing
JVC GZ-MS100 800x Digital Zoom Test
 |
 NIKON COOLPIX L19 80MP 36X ZOOM DIGITAL CAMERA AS IS  US $9.99
|
 NIKON COOLPIX L22 120MP 36X ZOOM DIGITAL CAMERA AS IS US $9.99
|
 KODAK EASYSHARE C143 120MP 3X ZOOM DIGITAL CAMERA AS IS US $9.99
|
 SONY CYBER SHOT DSC H20 101 MP 10X OPTICAL ZOOM DIGITAL CAMERA AS IS US $49.99
|
 Aquapack Underwater Digital Camera Video 8X Zoom New US $39.99
|
 Fuji FinePix Digital Camera 107x Opitcal Zoom US $175.00
|
 Casio EXILIM ZOOM EX Z35PE 121 MP Digital Camera Purple US $24.50
|
 Olympus CAMEDIA D 580 Zoom 40 MP Digital Camera Silver Many extras US $49.99
|
 Olympus 14MP 5X Zoom Digital Camera $10999 TADD US $5.50
|
| Powered by phpBay Pro |
|
CDN DTQ450X ProAccurate Quick-Read Thermometer
List Price: |
DescriptionNSF approved. 6-8 second response. Water proof and shatter proof. Data-hold. Big digit. Food-safe abs plastic. Recalibratable. On/off button. Temperature guide on sheath. Sheath can be used as handle extension... |
 |
Fagor 670040230 Stainless-Steel 3-in-1 6-Quart Multi-Cooker
List Price: |
DescriptionFagor's 6-qt. Electric Multi-Cooker is a pressure cooker, a slow cooker and a rice cooker in one. It also features a brown and a warm function for a truly one-pot-cooking, and a six quart removable cooking pot that is dishwasher safe and nonstick coated for easy cleanup... |
 |
PUR CR-6000C 2-Stage Oval Water Pitcher with LED Indicator
List Price: |
DescriptionThe PUR CR-6000C Two-Stage Pitcher with LED Indicator showcases an innovative two-step purification system that removes 99.9% of microbiological cysts, such as cryptosporidium and giardia, as well as common water contaminates, like lead and chloride... |
 |
Frank & Back To Black
List Price: |
Description2008 four CD box set from the talented and troubled British Soul vocalist. This hardcover book package contains the two CD deluxe versions of both of her albums (2003's Frank and 2006's Back To Black) for a grand total of four soulful silver platters... |
 |
Astral Weeks
List Price: |
DescriptionJapanese only release features 2008 remastering. The US pressing hasn't been remastered since it was originally issued on CD back in the '80's. Warner. |
 |
Zoom Karaoke - Adele
Sale Price: $8.99 |
 |
Howard Leight R-01526 Impact Sport Electronic Earmuff
List Price: |
DescriptionTo capture low level sound, the Impact Sport employs built-in microphones that amplify range commands and other important sounds. Users enjoy full, clear directional hearing in stereo. For protection, the Impact Sport actively listens and automatically shuts off amplification whenever harmful sound levels are reached... |
 |
Farm Innovators Thermo Cube Thermostatically Controlled Outlet
List Price: |
DescriptionThe Thermo Cube is a unique, patented electrical device that plugs into a standard 15 amp electrical outlet and turns power on automatically according to outside air temperature, saving money by using power only when temperatures require heating or cooling... |
 |
Wireless IP Pan/Tilt/ Night Vision Internet Surveillance Camera Built-in Microphone with Phone remote monitoring support - Black
Sale Price: $51.79 |
DescriptionSpecs: |
 |
Star Wars, Episode IV- A New Hope (Widescreen Edition)
Sale Price: $59.99 |
DescriptionStar Wars Episode IV: A New Hope, 2004 release, SINGLE DISC FROM TRILOGY |
