Megapixel Question

I overheard to people talking today about megapixels and the ability for the human eye to detect a difference.

The statement that I remember was that anything above 5.0 megs, we can't tell the difference by looking at it (if it's in focus).

Has anyone heard about this? Could it just be that the very high meg pics are better for printing?

Thanks in advance for your responses

Not Sure but I think the human eye can detect more then just up to 5 mp.

BTW heres some info: film cameras by comparision create a 6 to 7 megapixel quality.

and 4 megapixel is what you would want for a 8x10 print out.

I think the biggest reason for higher megapixels is so you can crop out parts of pictures that you don't want without hurting the quality of the picture that you want to print. Anything lower than 4 megapixels for an 8x10 print will result in a lower quality more blurred picture.

Thank you both. I have seen that about the 8x10 using the lower resoultion but did not know that about film.

Thanks again!