thanks for your replies so far.
i only got the 60mm last week to start a project for indoor "portraits" of artists (painters, sculpturers, designers) in their habitat.
i found no use for the 150 but was afraid the 60 would give me too much distortions if i portrait them too close.

why do you find the 150 most suitable for landscapes? and the 60 for portraits?
i was convinced it would have been the opposite:
slight telephoto for portraits; slight wide-angle for landscapes.

about image quality: which of the three gets best (theoretical) results?