We eventually timed ourselves, and we were able to change lenses in as little as 7 minutes; however, with long focal, it was much more complex, and our average time was closer to 20 minutes. The most complex rig manipulation was low mode, where the reflective camera looks down the mirror; we needed that configuration to get the camera very close to the ground, down to 5 cm rather that 30 cm. (You want to avoid this for normal shots, because the mirror catches more dust.) Turning the whole rig upside down and recalibrating the lenses took us 15 to 30 minutes, depending upon the focal length. Do that twice to get back to normal configuration, and it’s an average of 40 minutes of lost time. However, we managed to get these shots first thing in the morning or last thing at night, so that the time waste was halved.