How long do I have to be in the sun to get the minimal amount of Vitamin D needed for the day?

Also, does it matter on which part of my body the sun hits?

And finally, if I wear Sun Block lotion to stop the sun from tanning me, will that prevent me from getting the Vitamin D from the sun?

I am 19 and am a male! Thank you!

Where? You could sit in the sun all day this time of year in Pittsburgh or for 10 minutes in Florida.

Thanks!

Why do you think you aren't getting enough from your diet?