We performed photometric observations of the S255, S257, S140, NGC7358 and the Orion Bar photo-dissociation regions (PDRs) at 2 micron using narrow-band filters centered on the Br-gamma, H2 and [FeII] lines, as well as the narrow-band Kcont and the broad-band H filters for continuum subtraction. The observations were done with the 2.5-m telescope of the SAI Caucasian Mountain Observatory and the near-infrared camera and spectrograph ASTRONIRCAM. We find several high-density arc-like structures in the Br-gamma and [FeII] images of the ionized gas in NGC 7538 and extended shells and arcs visible through the H2 emission. The H ionization front and H2 dissociation front are merged in NGC 7538. In S 255 and S 257 we detected only Br-gamma emission from the H II regions and bright H2 emission from the PDRs. The projected distance between the H ionization and H2 dissociation fronts are approx. 0.3-0.4pc, which cannot be explained using models of a uniform medium. Most probably, the ionized and neutral gas in these PDRs is clumpy. The H I-to-H2 transitions in the NGC 7538, S 255, S 257 and S 140 PDRs are gradual with no sharp borders. This conclusion also agrees with the suggestion of a clumpy medium.

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