Hello Alexey and thank you for your reply
The stereobase is 10 cm, distance to the target around 2m and focal length 12mm. According to my calculations, that gives a disparity of 0.6mm in the sensor, which is more than 40 times the size of the pixels. In those conditions, our own reconstruction software (in this particular applicationwe use Photoscan as a backup/reference) works fine...
I have tried to lock the calibration parameters of the cameras (stereobase, focal and distorsion coefficients), as those are well known. However, it is very difficult to set a stereobase of 10 cm fixing the GPS locations of the cameras! Maybe there is a more clever way to do it? I imagine this application is a little bit out of the intended domain for Photoscan (I think you have a product Stereoscan or something like this better suited), but it would be very helpful if we could manage to use it at least as a backup solution...