What are the Differences Between Optical Zoom and Digital Zoom?
Optical Zoom and Digital Zoom
Many cameras today come with Optical Zoom and Digital Zoom but very few people understand the differences between Optical and Digital Zoom and which is better.
The Differences Between Optical Zoom and Digital Zoom
All SLR cameras come with Optical Zoom. What happens is the camera uses the lens to bring the subject closer. Digital Zoom simulates the zoom effect, but the process, and therefore the result, is different. What a digital camera does is to select a portion of the screen and enlarge it. Naturally this means that you lose some image quality. Were all other characteristics of two cameras identical, the results from an Optical Zoom would be superior.
Another difference is that Digital Zoom can be applied in the edit, that is, afterwards, while Optical Zoom can only be used at the time of exposure. All digital cameras have Digital Zoom. A digital zoom effect, of course, can be achieved in the editing process, so, in one way, the fact that a camera is described as having a 5x Digital Zoom, is not significant.
To sum up, Optical Zoom gives you better definition and is more significant as a characteristic of a camera than Digital Zoom, which all digital cameras are capable of anyway. If you do buy a camera with a Digital Zoom feature, make sure that it can be switched off when not needed. If your prints are not going to be larger than 4x6 inches, the loss of image quality when using Digital Zoom will not be significant.
The Connection Between Optical Zoom and Resolution
What about the connection between Optical Zoom and resolution? That is, what is the relationship between the megapixels, (MP), used to create a picture and Optical Zoom? Really, there isn't one. If you have a 2MP camera it will utilize 2 million megapixels to take a picture. A 3MP camera will have another 1 million MPs available to take a picture and therefore the picture quality will be better. Using Optical Zoom will not affect the number of megapixels used and therefore will not influence picture quality. It makes no difference if you have a 3x Optical Zoom or a 4x Optical Zoom. The resolution will be the same as it is dependent on the megapixels.
If you like using Digital Zoom, you need to decide what is more important to you, Digital Zoom or picture quality. A 2MP camera will give you good quality 4x6 inch or 5x7 inch pictures. A 3MP camera will give you good quality 8x10 inch pictures.
But, What About Smart Zoom?
Just when you thought it couldn't get more complicated, Sony has recently developed something called' Smart Zoom'. If your camera produces a 5MP picture and you decide to save an image of say, 2MP, what the Smart Zoom does is to use the 'spare' 3MP to enhance the picture you are taking so there is no loss of quality. There is, of course, a loss in terms of size as you can only use this facility if you are selecting a smaller image size.
So, Optical Zoom is more important, more significant in the assessment of a camera and offers better resolution than Digital Zoom. Smart Zoom is an Optical Zoom feature which solves the problem of picture degradation, at the cost of size. It's a trade off.
Photograph by Claudio Matsuoka
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Most folks feel that bigger is better when it comes to digital zoom, but depending on the camera you could be in for a real disappointment.