Correlation between the radial location of the peak ellipticity, a_ε and the bar length, R_bar, 1 (obtained from the constancy of the phase-angle ϕ₂) at different times (top panel). Correlation between the photometric length of the bar, obtained from the constancy of position angle of fitted ellipses, L_bar and the bar length, R_bar, 1 (bottom panel). In each case, a straight line of the form Y = AX + B is fitted (black dashed line), and the corresponding best-fit values are quoted. The Pearson correlation coefficients are quoted in the top left corner of each sub-panel. The grey dotted line in each sub-panel denotes the one-to-one correspondence. Both the photometric estimators overestimate the length of the bar.