Digital Zoom on digital cameras

Week 15, 2003

 Q) The digital camera I was considering- the Canon S30- is being discontinued. During my search, a new camera has surfaced–the Canon A300. It’s supposed to be a fixed auto focus, but has a digital zoom–how is that possible? Anyway, it’s 3.2 megapixels and is selling for $199. Your thoughts on this camera and what I should do?

-Susan I. Greenberg, McMurray, PA

A) Though I have a very high opinion of Canon’s products and customer support, I would recommend you move beyond their A300 and try to find a leftover Canon S30 somewhere. This is because of the lack of an optical zoom on the A300. While most cameras have both optical and digital zooms, you should only use the optical zoom range as a basis for comparing cameras. A digital zoom is not really a zoom at all. A better term for it would be a “digital crop”.

A digital camera with an optical zoom uses 100% of the digital camera’s sensor. As you zoom in and out, the lens changes magnification and the image falling on the sensor changes. With a digital zoom-only camera, the image falling on the sensor never changes as the lens cannot change magnification. The zoom effect is created by internally cropping the picture. Because you are cropping the picture, you are using less of the sensor and picture quality goes down. It’s like turning your 3 megapixel camera into a 1 or 2 megapixel camera- not good.

The digital zoom feature isn’t needed at all if you will use a computer with your digital camera, as most people do. Almost all digital cameras come with basic image editing software such as Adobe Photoshop Elements or Arcsoft Photo Impression. These image editing programs allow you to crop and modify your pictures after they are downloaded to your computer. The end result is exactly the same as if you did the cropping with the camera.

As a side note, looking at the A300 on Canon’s website, the flash is very close to the lens. Proximity of the flash to the lens is largely what causes redeye in pictures. Have you ever noticed that professional photographers very rarely, if ever, get redeye effect in their photographs? This is because they use a flash that is mounted on the camera, rather than built into it. This moves the flash away from the lens and largely eliminates redeye.

While most cameras these days have a built-in flash, the smaller the camera, the closer the flash to the lens and the more likely you are to get redeye. If you have a digital (or film, for that matter) camera that has an accessory shoe for mounting an external flash, I strongly recommend you buy one and use it instead of the built-in flash. You won’t believe how much better your flash pictures will be. If you must use a built-in flash, using your zoom at the widest setting will help reduce the incidence of redeye.

Does all of this mean that the Canon A300 is a camera that should be avoided? Not at all! There is a very big difference in the picture quality between a 2 and 3 megapixel camera. 3 megapixels is where results rivaling 35mm film start becoming obtained. $199 for a Canon digital camera with 3.2 megapixels is a real breakthrough, and the A300 will deliver wonderful results for those willing to learn how to use it properly. Using it properly would mean forgetting about the digital zoom, and zooming like everyone did in the old days- with your feet!



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