How Does Huygens' Wave Theory Explain Blurriness in Pinhole Images?

[T@P]

i just learned this in physics, and i don't quite understand something:

according to Huygens, (i think) light is a ciruclar wave, and at everypoint on the wave there are wavelets. because there are so many ways for the wavelets to form, light takes every possible path from point a to point b. that parts sort of makes sense. then, all the really weird paths get cancelled, out and you are left with essentially a cone of light.

the above (if i got it right) sort of makes sense. but what doesn't is that this is supposed to explain why when you make a pinhole that's too small you get blurryness. shouldn't you just get the image to be not as bright? i don't quite see where the blurry part comes in.

 

[shyboy]

If you have a small pinhole, you can get a diffraction from opposite edges.
So, if you ahe a single source, you will get a bright central (main) peak and a lot of small peaks resulting from the diffraction. http://upload.wikimedia.org/wikipedia/en/e/e1/Diffraction1.png

The smaller the hole the stronger will be peaks. For a circular hole , I guess, you have additional rings. So your total image, produced by multiple sources will be blurred.