T. Kim, S. Sridharan, and G. Popescu, Gradient field microscopy of unstained specimens: reply to comment, Opt. Exp. 21 (16), 19188 (2013).
We reply to the comment written by Ferrari and Ayubi on our recent paper, Kim et al. [Opt. Express, 20, 6737 (2012)]. We maintain that our use of Fourier filtering methods lead to valuable intrinsic contrast live cell imaging. Judging by their comments regarding the limit sin(x)~x, it seems that the authors overlooked Fig. 2 in our paper, where we show results with sinusoidal masks of different periods.