Top row: difference between the velocity dispersion measured (σ_out) and that provided as input (σ_in) in the model as function of σ_in for galaxy S2F1-511. The template adopted in the simulation have solar metallicity and age 2, 4, 5 Gyr from left to right. It is evident that the age of stellar populations do not affect our measurements. Bottom row: same as top row for the template with age 3 Gyr and subsolar, solar and super-solar metallicity from left to right. The three panels show that our uncertainty on stellar metallicity does not compromise our σ estimates. The red solid line is the median of the distribution, while the dashed lines are the 25th and 75th percentile.