Q) My new lens came with a weird-looking lens shade. When do I use it? I’m told I should use it to avoid flair with the sun. Is that the only time?
Devin S., Via the Internet
A) If someone is watching you, you should always shoot with “flair”! What you want to avoid is flare. Many people think of flare as those reflections of the sun that show up as colored spots in your image. In reality, flare is any extraneous light that starts bouncing around your optical path. It’s something optical designers struggle to reduce in all of their lens designs. That’s why the metal and plastic interior parts of lenses are black-to reduce flare.
While you might notice the more obvious signs of flare in your image, you should use your lens shade even when you can’t see the “spots”. If you don’t, you may end up with a more subtle form of flare that reduces your image’s contrast.
One final reason to use your lens shade: it helps protect the front of the lens from damage.