Log_LDR

unsigned int LDR = 512;
float Calc1 = 0;
float Calc2 = 0;
float Calc3 = 0;
float LogCalc = 0;
//-----------------------
void setup()
{
  Serial.begin(9600);
}
//---------------------------------
void loop()
{
  Calc1 = map(LDR, 0, 1024 , 0, 470);
  Calc2 = (Calc1/470) * 10;
  LogCalc = log10(Calc2);
  Calc3 = 470 * LogCalc;
  Serial.println(Calc3);
}