For years I have believed I should in no circumstances use digital zoom available on my phone camera. Today I finally decided to test it. First of all for my surprise the pictures where zoom used turned out they are same size in pixels as in photos where no zoom used. Then I had a look on them at PC screen… …
For my surprise the picture taken with digital zoom looks even a bit better and sharper than if I would just crop the same area from photo where no digital zoom used. All these years I have believed it's better not to use the digital zoom because one can just crop the same afterwards. But now I'm not so sure anymore. At least the quality is not very different, thus suggesting it's just alright to compose the wanted area already on the spot using digital zoom.
There is of course the limits how much zoom-in is reasonable to use. The number of pixels the sensor can produce is limited. Too much digital zoom and it is just an awful pixel mess. But in certain limits digital zoom works just alright. Moreover it is important to understand this experiment of mine is only for online media. My camera phone is capable for 3.2 mega pixels which means I get 2048x1536px pictures. So, there's plenty to crop for pictures usually presented on Web sites. For example I usually downsize the pictures in my MyOpera albums to 1280×960 pixels.
UPDATE 2010-09-09: The ultimate question is whether the interpolation algorithm on camera works better than it does on photo editing software when decreasing the size or cropping images for Internet. For print media it is still better not to use digital zoom of your camera phone but just walk closer to the subject to catch the pertinent if possible 😉
Digital Vs Optical Zoom by Panther Products
Digital image interpolation: Note on optical vs. digital zoom by Cambridge in Colour