Left panels: Isophotal analysis of the i-band image of NGC 4277. The radial profiles of the surface brightness (upper panel), position angle (central panel), and ellipticity (lower panel) are shown as a function of the semi-major axis of the best-fitting isophotal ellipses. The vertical black lines bracket the radial range adopted to estimate the mean ellipticity (⟨ϵ⟩ = 0.242 ± 0.002) and position angle (⟨PA⟩ = 12327 ± 032) of the disc. Right panels: Fourier analysis of the deprojected i-band image of NGC 4277. The radial profiles of the relative amplitude of the m = 2 (blue points), m = 4 (green points), and m = 6 (yellow points) Fourier components (upper panel), bar-interbar intensity ratio (central panel), and phase angle ϕ₂ of the m = 2 Fourier component (lower panel) are shown as a function of galactocentric distance. The vertical red lines in the central and lower panels mark the bar radii R_bar/ibar and R_ϕ2, respectively.