We report the results of CCD V and r photometry of the globular cluster NGC 5466 .
The difference image analysis technique adopted in this work has resulted in accurate time series photometry even in crowded regions of the cluster enabling us to discover five probably semi-regular variables .
We present new photometry of three previously known eclipsing binaries and six SX Phe stars .
The light curves of the RR Lyrae stars have been decomposed in their Fourier harmonics and their fundamental physical parameters have been estimated using semi-empirical calibrations .
The zero points of the metallicity , luminosity and temperature scales are discussed and our Fourier results are transformed accordingly .
The average iron abundance and distance to the Sun derived from individual RR Lyrae stars , indicate values of [ Fe/H ] = -1.91 \pm 0.19 and D = 16.0 \pm 0.6 kpc , or a true distance modulus of 16.02 \pm 0.09 mag , for the parent cluster .
These values are respectively in the Zinn & West metallicity scale and in agreement with recent luminosity determinations for the RR Lyrae stars in the LMC .

The M _ { V } - [ Fe/H ] relation has been recalibrated as M _ { V } = + ( 0.18 \pm 0.03 ) [ Fe / H ] + ( 0.85 \pm 0.05 ) using the mean values derived by the Fourier technique on RR Lyrae stars in a family of clusters .
This equation predicts M _ { V } = 0.58 mag for [ Fe/H ] = -1.5 , in agreement with the average absolute magnitude of RR Lyrae stars calculated from several independent methods .
The M _ { V } - [ Fe/H ] relationship and the value of [ Fe/H ] have implications on the age of the globular clusters when determined from the magnitude difference between the horizontal branch and the turn off point ( HB-TO method ) .
The above results however would not imply a change in the age of NGC 5466 , of 12.5 \pm 0.9 Gyr , estimated from recent isochrone fitting .