How much sun do you need to get to meet your vitamin D requirements?

And does it count if you are inside but the sun is shining through a window on to your skin, or do you need to be outside?

Vitamin C for Wrinkles and Sun Damage

Vitamin C is one of the only scientifically proven wrinkle fighters on the market. You are probably seeing a lot of new vitamin C beauty products hit the shelves of drug stores and department stores. Unfortunately, vitamin C oxidizes very rapidly in these products and you may not be getting the benefit of the vitamin [...]