It was more in regards to focus capability and not light loss. There is so much distortion in a "kit" lens that using a slightly distorted UV filter does not really affect its performance in any noticeable way.
This is hardly a universal truth Don, please stop spouting it like it's gospel.
Obviously, you have not shot with a SONY 18-70 lens. You would really have to have something god-awful to make it work worse.
If everybody made the "mistake" of religiously buying good filters ... who is it going to hurt? Huh? YOU? THEM? Cut your losses and get involved is some other protest. Good gosh!
Don Schap - BFA, Digital Photography A Photographer Is Forever
Look, I did not create the optical laws of the Universe ... I simply learned to deal with them.
Remember: It is usually the GLASS, not the camera (except for moving to Full Frame), that gives you the most improvement in your photography. flickr® & Sdi