Why is Digital Zoom bad?

From what I understand, EDIT: Digitall Zoom is "bad". I just want to know why.
Wouldnt it be better because you actually get more zoom, resulting in a more accurate (so to speak) shot?

Perhaps you are thinking about "digital" zoom. Optical is good as far as the two go.

optical zoom is the way to go. I still uses the entire sensor surface. Digital zoom takes a portion of the sensor and crops in camera.

Hahahah My bad! I ment digital.
Edited^^

gjl- Im still a little confused?

Digital zoom isn't really 'zoom'

It doesn't do anything except crop the picture. Nothing you can't do on the computer. It's like zooming in inside photoshop or whatever program you use - it doesn't give you any more actual pixels.

oni0n56 pegged it. But I have seen two different methods. First is the simple crop. Say your sensor is 100 by 100 pixels. You have a 10x digital zoom and can zoom into just the center portion and create a 10x10 pixel picture. There are a few cameras that do it a bit differently. Again, you have a 100 x 100 sensor and the 10x zoom. This time the camera take the 10 x 10 pixels from the center and makes a 100 x 100 picture from it. You have no more detail than the 10x10 but it is the same size of the 100x100. The end result is lots of pixelization.

Digital zoom enlarges a section of the image--the section into which you "zoomed." It increases the size of the pixels and then crops the section leaving you with a low-resolution image that often is not even suitable for viewing on-screen much less printing. Most Canon point and shoots I've seen have a menu option that permits you to turn off digital zoom.

I understand digital zoom, but I'm curious as to why it's even an option these days, since most folks don't use it. Does it have a purpose?

O_T wrote in post #2486262
I understand digital zoom, but I'm curious as to why it's even an option these days, since most folks don't use it. Does it have a purpose?

Lots of folks do not want to do any post processing. My 80 year old aunt for one, and my 75 year old father in law for two. I guess it's also a marketing gimmick. That way manufacturers get to sell a 30x zoom still camera and a 700x zoom video camera. Big numbers impress lots of folks.

gjl711 wrote in post #2486198
oni0n56 pegged it. But I have seen two different methods. First is the simple crop. Say your sensor is 100 by 100 pixels. You have a 10x digital zoom and can zoom into just the center portion and create a 10x10 pixel picture. There are a few cameras that do it a bit differently. Again, you have a 100 x 100 sensor and the 10x zoom. This time the camera take the 10 x 10 pixels from the center and makes a 100 x 100 picture from it. You have no more detail than the 10x10 but it is the same size of the 100x100. The end result is lots of pixelization.

That's called interpolation. Some cameras use that to have artificially high megapixel values. But half of those pixels come out of its @$$.

yea, digital zoom is bad, its basically cropping the picture and decreasing detail... you can get the same effect as digital zoom by using the crop tool in photoshop, for example.

Generally I agree on the comments but I'd like to add my 2 cents.

In the P&S world you can normally only save as JPEG, a 'smart' digital zoom of no more than x2 may give you a slightly better photo than a crop later in Photoshop because the JPEG will be less compressed when stored in the camera for the lower resolution image. Certainly going more than x2 on digital zoom is insanity under any circumstances.

There is actually something worse than digital zoom and that would be a cheap tele-converter. Some of the third party accessory lenses are complete rubbish and digital zoom actually does less harm to the image quality. The no more than x2 digital applies here also.

Thanks for all the help guys. And thanks to the mods for editing my thread title!
I think I understand it now...But if I am looking to get a really far shot digital zoom would still make no difference as opposed to having the digital zoom off?

Digital zoom does nothing but crop the image.