You may have heard that in Canada, it is literally impossible to absorb enough vitamin D between the months of October to March just due to where we are located on the planet in relation to the sun. It's a fact that always blows my mind to be honest.
Now that the sun IS here how much do we need to get the good stuff? Here is where it depends on your skin colour. In general, though, you can get between 10,000IU and 25,000IU in less time than it takes to change your skin colour (ie. burn) so don't feel like you have to become a lobster. The Vitamin D Council has a cool chart that categorizes natural skin pigment. Pale skinned folk will make vitamin D more quickly, let's say in 10-15 min, vs a dark skinned person who may take up to 2 hrs to make the same amount.
And the elephant in the room with getting out vitamin D naturally is of course UV rays and skin damage. UV exposure also makes skin look older and can cause skin cancers.
What do we do? Get some sun exposure while keeping in mind your skin type and health history. Some = less than the time it takes you to burn! Other than this you should be lathering up with some biodegradable SPF 30 and applying it frequently. If you want to cover your bases and stay looking younger for longer, consider a vitamin D supplement. Most supplements are pretty good, I always recommend a liquid vitamin D in some sort of MCT oil because it will be best absorbed in this format (don't waste your money on something you won't get the full benefit of!).