Answer
The range of frequencies is from $7.5\times10^{12}\,Hz$ to $6\times10^{13}\,Hz$.
Work Step by Step
Frequency $\nu=\frac{c}{\lambda}$ where $c$ is the speed of light and $\lambda$ is the wavelength.
The camera detects frequencies between
$\nu=\frac{3.00\times10^{8}\,m/s}{40\times10^{-6}\,m}=7.5\times10^{12}\,Hz$ and
$\nu=\frac{3.00\times10^{8}\,m/s}{5\times10^{-6}\,m}=6\times10^{13}\,Hz$
