What is the difference between optical zoom and megapixel?

Question

Looking to get a new camera for amateur photography. I love taking close up shots of animals and children (I am a teacher) but can't stand when the pic gets "grainy". I was thinking of a Kodak Easy Share 12x zoom/10.1 megapixel.

Answer 1

Ian had a great answer but I'll boil it down a little for you:

Optical zoom is the difference between the widest field of view and the closest. On a 12x lens an object will be 12x bigger when you zoom all the way in than when you have it zoomed all the way out.

Megapixels are the number of physical pixels on the light sensor (CCD). 1megapixel is 1,000,000 pixels. More megapixels generally means you can print your photo out larger but it can sometimes lead to more grain in your images because the pixels need to be smaller if you have more of them. That being said, 10.1mp should be fine.

If you want to avoid grainy images make sure you use the lowest ISO setting possible for the situation. The more light you have the lower the ISO you can use.

Answer 2

You have crossed terms over a little.

Optical zoom is rating of how many times the focal length of the lens the mechanically activated zoom will go to, while a digital zoom is achieved by electronically magnifying the image that the CCD has received from the optics, and therefore may be subject to a graining effect or other loss of sharpness.  Cameras use processing logic to compensate for this by enhancing the image a little as it is recorded, with varying success, but of course with a longer optical zoom you won't make much use of digital.

Not all camera bodies and their electronics, lenses and CCDs are created equal, obviously.  In megapixel terms, 10.1 is a good number, but the overall quality of the CCD, how well the electronics process the image from it, and how good an image is provided by the lens on the front are all going to affect the overall result.  I remember a racing driver once saying that it wasn't all about horsepower, it was about how well his car put the power down on the road.  I think that is analogous to digital cameras.

I think you refer to the Kodak Z1012 and my impression is that this is going to produce very reasonable quality. There are so many cameras in that market sector, Panasonic notably using Carl Zeiss lenses, but I don't think you will go far wrong with any of the leading brands at that price level, all will provide images suitable for any reasonable level of enlargement for framing at home, and operate well under most average shooting conditions for a home user.

My own experience with a similar model from Fuji teaches me that 10x optical zoom and upwards, with an average length lens, will allow good results filming general activity and reasonably close-up portraits.  You can fill the frame without having to get in someone's face and there's enough quality there to zoom a bit more afterwards at home.