Quasiconformal mappings are powerful tools in the study of one-dimensional holomorphic dynamics. We give some simple estimates on the effect of deformation of conformal structure by Beltrami coefficients and discuss their application to the problem of pointwise corformality, parametric differentiability and construction of wandering domains for a transcendental entire functions of Eremenko-Lyubich class. The last result was inspired by a work of C. Bishop and

joint works with David Marti Pete.