The low-lying level schemes and electromagnetic transitions of Te-109, I-109, and the neighboring even-even nucleus Te-108 are calculated within the framework of the SD-pair approximation of the nuclear shell model. Good agreement is obtained between the calculated results and experimental data. The favored components of low-lying bands are discussed in the collective nucleon-pair subspace. The weak-coupling picture shown in these nuclei and its relationship with residual quadrupole-quadrupole interaction between valence protons and neutrons are analyzed.