3 questions for NikonCP5700

[roycehua]

I've bought my CP5700 for 3 weeks, and very like it's photo quality.But there're 3 questions always bothering me there days, did any one who can help me?Many thanks!!
1. The EFV's rubber always easy to get dust on it.
2. It looks no difference when I adjust the EXP and using the Speedlight at the same time(no matter -2~+2). But if I shot down the Speedlight, it works normal. Why?
3. When I zoom in,the motor seems gets more and more noise when it closer to the max. tele. (280mm), is that normal?
Thanks!!