We collect thousands of photos from our municipality with our little drone and our goal is to create survey grade ortophotos and a presentable 3D model for the web. When adding the photos to Context Capture I assume camera data would be the same for all photogroups, but surprisingly they show varying focal length.
Camera data is listed in the database and should be fetched from there, so what causes the program to set different focal lengt to photos taken with the same drone camera at more or less same altitude all the time?
Am I worrying for no reasons, does the altered focal length affect any of our results, or is it just something to accept and forget?
Happy for any ideas!
/Anders Theodorsson, Ludvika Municipal GIS-data office
Focal length is read from EXIF data so it is problem with drone. Camera data only takes sensor size and photo resolution.
It may still run but each protogroup will have it's own calibration.
So do you think I should alter the focal length manually when I detect differenses?
Yes. Also try to ask DJI what is happening. Seems it tries to calculate focal length based on focusing.
Hello Oto!
I'm still struggling with the fact Contaxt Capture ends up with curved and corrupt results from Aero Triangulations. Camera calibration done several times and the results are never the same. Different focal length and "35mm eq." every time I run a new calibration. That can't be right!
Still wondering if I should enter the calibration values from Bentleys camera data base and fix them or run my own calibration in every single project? Depending on which photos I pick out to run the calibration I get different results every time! I can’t understand how a camera with fixed lenses can obtain so many different focal lengths?
Are these screenshots before or after aerotriangulation?