The aspect ratio is the relationship between an images width and height. Many models will allow several different aspect ratios to be captured depending on the settings.
When an image is captured at a reduced aspect ratio, compared to the sensors native ratio, parts of the sensor are not utilized. This means that there is less material to stitch together, requiring more photos to cover the same area. It can also negatively impact the camera calibration reducing the accuracy of the final model.
For the best results set the aspect ratio to your cameras native aspect ratio.
For example the DJI Phantom 4 Pro and RTK have a native aspect ratio of 3:2 (5472:3648). While the DJI Zenmuse X5S has a native aspect ratio of 4:3 (5280:3956).
I still can't do it!
We wrote these articles to arm you with everything you need to get the job done on your own, but we understand that sometimes this isn't sufficient.
If you're stuck, the Propeller data success team may be able to help. You can contact our support team by clicking the support tab on the top right pane of your user portal.