Optical and digital zoom question

What is the difference between digital and optical zoom on a digital camera?

Thanks /ubbthreads/images/graemlins/smile.gif

digital zoom is useless other then seeing something thats far away it is like zoom in a computer picture edit program man i hope i made sence

Optical zoom involves changing the magnification due to the optics of the camera - the lens its self is responsible for optical zoom.

Digital zoom is a useless feature that got added to digital cameras to make outrageous zoom claims for marketing purposes. Digital zoom merely takes a crop of the picture and resizes it to the full resolution of the cameras output files.

For instance, if the camera's CCD resolution (and output files) are normally 1280x960, then 2x digital zoom will take the center 640x480 pixels from the CCD, then resize that image data into a 1280x960 image. You do not gain any more detail from digital zoom, whereas with optical zoom, when you zoom in, you gain more detail as well.

Optical zoom makes the picture image bigger on the CCD sensors (pixels). Digital zoom (in the camera viewer) displays a small segment of the full (raw) CCD sensor image as the full frame of your little screen. Digital zoom (when taken and stored by the camera) means the camera took that small segment of the CCD image and compressed it into the full frame jpeg image you have stored.

Digital zoom on your computer screen later means that the jpeg picture has been decompressed into screen pixels, and that you're viewing a smaller segment of the decompressed picture as your image.

Because of this, if you are going to want to see an image enlarged more than your optical zoom can accomplish, it is better to digitally zoom the camera in, because that will give a better image than taking a regular picture and then zooming into the picture as it is displayed on your screen (or enlarging your print). This is because digitally zooming in "playback" will enlarge decompression artifacts that wouldn't be there if you compressed a picture that was digitally enlarged before compression.

Or something like that.

Nerdengineer said....
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f you are going to want to see an image enlarged more than your optical zoom can accomplish, it is better to digitally zoom the camera in, because that will give a better image than taking a regular picture and then zooming into the picture as it is displayed on your screen

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I tend to do it the other way. The PC software is frequently quite good at extrapolating (guessing at) the pixels between two pixels.

Some camera's use a digital zoom that very accurately extrapolates the values between pixels by doing a hardware trick that makes the sensor more sensitive to collect the extrapolation information.

It all depends on your software and camera. Only experimentation will tell you which is better with your setup.



Daniel

i must admit my pansoicis digital zoom aint bad it has 12x optical and with digital it is 48x i can zooom in on anything with digtal and 12x optcal is very good to

I've experimented and I can do a better job with software resizing (actually cropping) then the digital zoom offered in a couple of different digital cams I've tried the digital zoom on.

but many times ive noticed there is something i cant even see with out the digtal zoom /ubbthreads/images/graemlins/smile.gifbut if ya can see it it is better to use softeware

Most seem to, as a basic rule of thumb, avoid digital zoom. If you have the option of using optical zoom, where your CCD is actually capturing more of the desired picture, you do not have to rely on some algorithm to interpolate what pixils it thinks should be in your picture.

Again, the quality of the digital zoom will vary from camera to camera based on the quality of the firmware (camera's software), just as the effectiveness of optical zoom depends on the quality of the lens.

If you have the option of getting a camera with a decent amount of optical zoom, it will allow for more possibilities as far as editing your pictures later and more than likely any prints you make will look much nicer.

-Brad

Digital zoom is fun to play with, but useless for actually shooting any footage you'll want to use and not look like a blow up of a security cam picture on some cop show.

So if you can get more optical zoom, go for it. 200 or 400 or whatever silly huge number for digital can be useful if you're trying to spot something far away through the view finder, but you won't want to use it often.

here's a technique to make a macro lens if you only have a digital zoom camera.

Take florencent light with large lens. place over what you are trying take macro photo of. compose photo like you normally do and be surprised at results.

Great idea cy! I used to see those kind of magnifier lights a lot. Maybe they are still common and I just don't notice anymore. Anyway, I'm gonna get me one.

When I first saw this thread I thought I knew that digital zooming actually had a purpose. I believed that the digital interpolation in the camera would yield a better result than trying to crop/zoom an image already converted to jpeg. I stand corrected and can only add to the opinions above this reference from dpreview.com. I imagine most of you are already familiar with this site but this is the first time I looked there for general digicam information instead of reviews.

http://www.dpreview.com/learn/?/Glossary/Digital_Imaging/Digital_zoom_01.htm

I also would add that if your camera can save images in raw format or a lossless compression format, and you have the space on your memory card, then it's a no-brainer to not use digital zoom.