  We performed a near-infrared (NIR, $\sim$1.0$\mu$m-2.4$\mu$m) stellar
population study in a sample of early type galaxies. The synthesis was
performed using five different evolutionary population synthesis libraries of
models. Our main results can be summarized as follows: low spectral resolution
libraries are not able to produce reliable results when applied to the NIR
alone, with each library finding a different dominant population. The two
newest higher resolution models, on the other hand, perform considerably
better, finding consistent results to each other and to literature values. We
also found that optical results are consistent with each other even for lower
resolution models. We also compared optical and NIR results, and found out that
lower resolution models tend to disagree in the optical and in the NIR, with
higher fraction of young populations in the NIR and dust extinction $\sim$1
magnitude higher than optical values. For higher resolution models, optical and
NIR results tend do aggree much better, suggesting that a higher spectral
resolution is fundamental to improve the quality of the results.
