Resulting images for five of the nine L dwarfs without a companion: the image on the left represents the added image of all four exposures taken in the F108N filter with the upper cut level reduced for a better visibility of the background (thus not representing the real peak values). The right image displays the final reduced image after the subtraction of the two filters. The positive signals visible in the central part of the final images of 2MASS 0051−1544 and 2MASS 0825+2115 are not simultaneously present in each of the individual reduced detector position images and are therefore residuals from bad pixels buried in the original PSF. The overall smooth result images confirm the correctness of our reduction procedure.