We've debated the idea that magic shields don't seem to block normal levels of light as you can see through them. However, the vague consensus was that magic shields had some kind of mumbo jumbo that at FTL detects a level of energy that is dangerous and blocks it. Otherwise, no shield you can see through would protect against energy weapons or certainly something like a nuke.
Now totally intense magnetic fields or gravitational fields can bend light but I won't want to be around one as they are galactic level.