In what situations is human vision grainy?

Question: In what situations is human vision grainy!?
Best Answer - Chosen by Asker:

Remember your basic biology!? Rods and cones!?
In very dark/night-time situations, when only the rod-shaped light detectors in the eye are effective, what we see can seem grainy!.
Without the cone-shaped cells, which supply colour and detail to the brain but require a lot of light to be effective, what we have left are the low-light sensors!.
These rods have evolved to work well enough for basic vision but do not supply 'daylight' quality, so what we see can be 'grainy'!.Www@QuestionHome@Com

After staring at this danged computer screen for too long !!! !.:!.:!.:!.:!.:!.:!.:!.:!.:!.:!.:!.:!.:!.:!.:!.:!.:!.:!.:!.:!.!.!. <--see: grainsWww@QuestionHome@Com

When on some types of drugs!.Www@QuestionHome@Com

foggy or very rainy dayWww@QuestionHome@Com

squint and its kind of grainyWww@QuestionHome@Com

On a super windy day at the beach!?Www@QuestionHome@Com