Can I correct pixel size after taking photo?

Question

I have a digital camera (Kodak EasyShare C613). Sometimes when I take a picture and transfer it onto my computer, the picture doesn't look right. I think I used the telephoto lens instead of the wide lens. You can see those little dots or squares in some pictures. Is there a way to fix the photo so that it looks right after it's been transferred to my computer?

Answer 1

Its likely that you are using too high of an ISO. Check in the Owner's Manual for your camera and see if it offers in-camera Noise Reduction. If it does, use it if you need a high ISO. If there is no in-camera Noise Reduction then a program like Noise Ninja may be needed. Its always best to use as low an ISO as possible.

There are 3 components to exposure: ISO, Aperture and Shutter speed.

ISO is the measurement of the sensitivity to light of a light sensitive surface, whether film or digital sensor. A low ISO indicates a low sensitivity and requires that A) more light has to be admitted by the lens or B) the shutter speed has to be slower to allow the light to properly expose the light sensitive surface or C) a combination of A & B.

For additional information, read Bryan Peterson's book "Understanding Exposure".

Answer 2

I don't know of any sure fire way to clean up what you are seeing, but maybe I can help with why you have the problem in the first place.

It sounds like you are describing a grainy picture.  For example you see a lot of pixels that are off color or not smooth like noise on a TV screen.  This is caused by using a high ISO setting.  

If you want a smooth photo you should not use any more than 100ISO on a PnS Digital Camera.  However, using low ISO means that it "exposes" faster, and your pictures are either darker, or need a longer shutter resulting in blurry pictures.

The answer would be, if you have enough light, make sure your ISO is set low.  If you don't have enough light, then it takes a higher quality camera.  If it was easy to remove noise in post, then they wouldn't be able to sell high end cameras easily, as they wouldn't be as needed (IMHO).

If you want to do more research, it has to do with the F-stop or Aperture of the lens.