Originally Posted by ol mike
What's the skinny on scope shades -do they diminish a scopes ability to gather light ? I like them because they seem help protect the objective lens .
They can help protect the objective but I think flip up lens caps protect better. You can use both.
There are two kinds of scope shades. One more common is simply a cylinder barely larger than the objective lens with a black interior. It reduces light from the sky or direct sun entering the scope. The only detriment is being bulky and a little weight. There is no image degradation. They can definitely improve contrast particularly with a high magnification scope.
Another type looks like a black coated honeycomb and fits in front of the objective lens. They are sometimes used by snipers to eliminate glint off of their objective lens being seen by others They shield at much narrower angles from the line of sight than a "normal" sunshade does. They do hurt image quality noticeably but hot as much a getting shot in the head.
Another form of sunshade is just a hat with a brim which keeps sunlight and skylight out of the eyepiece and you eye. A dark underside on the brim helps. A black ski mask can help in addition if the weather allows it. It's most useful in snow where light comes from the sides and below too. For shooting into a dark location a black cloth draped over the scope and shooters head can help a lot allowing the eye to dark adapt.