I don’t think you can absorb sufficient vitamin D in the shade, but you can do it without getting a sunburn. Direct sun exposure to your arms and legs for five to 10 minutes daily is sufficient for proper vitamin D production. -Quote from the Mayo Clinic I have very fair translucent skin, and even in the brightest sun it takes at least about 15 minutes for me to burn. Also, if you don’t want to expose your skin to direct sunlight at all, you can still get the recommendation for vitamin D by eating “foods that are naturally rich in vitamin D, including oily fish (salmon, mackerel, sardines) and egg yolks, [and] foods that are fortified with vitamin D, such as cereal, bread, milk and yogurt” or taking vitamin supplements. [same link; you might want to read it for more info about vitamin D]