Aerial photography overlap overspecified? What works?

[mks_gis]

Hi,

 The PhotoScan manual specifies 60% of side overlap + 80% of forward overlap for aerial photography. I'm struggling to plan a mission for this in Mission Planner, as the interval between pictures drops below 2 second if you do this. My A6000 camera cannot keep up with this pace and I get fewer images than CAM triggers; I need to keep above 2s for continuous shooting without dropping images. If I reduce the flying speed my mission time increases beyond the capacity of my battery. A balance needs to be struck.

 I have tested PS derived DEM vs differential GPS and with a 60% overlap and 70% side overlap I have achieved mean 4.3cm elevation error on a DEM. That's not bad at all.

 What are the experiences of other users? What overlaps do you specify and what works for you? Do you increase altitude or drop speed for instance? Change focal length (I shoot 35mm)?

Cheers

 

[mrb]

Do more flights if you can't get everything in one go.

[mks_gis]

Restrictions in time, batteries, tide, access to site might require a more complex approach.