I saw this movie in the early 90's so it was made before then and I think it was a fantasy all I remember is there was a girl who was taken and the hero was coming to save her and it was in a castle (I think) and to kill the witch or whoever it was he found all these mirrors and wiped them off and aimed them so the sun Shawn through them to the witch or something like that I just mostly remember the mirrors.

Legend (1985)
Starring Tom Cruise, Mia Sara, Tim Curry
Wikipedia synopsis excerpt:
Darkness tells her there will never be another dawn because he will kill the unicorn by sunset as light harms him. She agrees to wed Darkness if only she can kill the mare. Jack and his friends have found them and overhear, giving Jack the key to Darkness' demise. From the banquet preparations they take giant metal platters to design a heliotrope to reflect light before it sets, as Lili and Darkness prepare to sacrifice the mare. Lili frees the unicorn instead and Jack attacks Darkness while the others relay the light of the setting sun. Darkness shouts as he is blasted away by light that he can never be destroyed because he is a part of all of them.


You can read the rest here:
http://en.wikipedia.org/wiki/Legend_(film)

Here's a film clip:
Legend (10/11) Movie CLIP - Jack Defeats Darkness (1985) HD - YouTube