help needed with Camera switching code!

Projects General Guidance
2 
  this will switch betweencams facing either the annoucer, guest, news or still screen.

This implies 4 cameras.

int Cam1 = 3;
int Cam2 = 4;
int NewsCam = 5;

This implies 3. Why does one get a halfway meaningful name, and the other two do not?

int Mic1 = 8;
int Mic3 = 9;
int Mic4 = 10;
int NewsMic = 11;

Why does the still screen have a microphone? I presume that there is some (undefined) relationship between these microphones and the cameras. Though what that relationship is, when there are 4 of one and three of the other is not at all clear.

  //set mics to inputs
  pinMode(8,INPUT);
  pinMode(9,INPUT);
  pinMode(10,INPUT);
  pinMode(11,INPUT);
  
  // Enable internal pull-up resistor
  pinMode(8, INPUT_PULLUP); 
  pinMode(9, INPUT_PULLUP);
  pinMode(10, INPUT_PULLUP);
  pinMode(11, INPUT_PULLUP);

Make up your mind. You want the pins to be INPUT or INPUT_PULLUP?

Why are the pins now anonymous? You gave them names earlier (though not good ones).

  else if (digitalRead(10) == HIGH)
  {
    digitalWrite(Cam1, LOW);
    digitalWrite(NewsCam, LOW);
    digitalWrite(StillScreen, LOW);
    digitalWrite(Cam2, HIGH); //turns on guest cam
  }
  else if (digitalRead(9) == HIGH)
  {
    digitalWrite(Cam2, HIGH); //turns on guest cam
    digitalWrite(Cam1, LOW);
    digitalWrite(NewsCam, LOW);
    digitalWrite(StillScreen, LOW);
  }

The guest gets two switches?

  else (digitalRead(8) == LOW && digitalRead(9) == LOW && digitalRead(10) == LOW && digitalRead(11) == LOW);

If all of the switches are off, do nothing (that's what the ; at the end means). Otherwise, no nothing. I'll bite. Why?

all help is welcome

First, you need to describe what the problem is (besides the obvious stuff above).