Using OpenSFM with a telescopic lens

[pburke11]

I have a set of images which were taken with a telescopic lens, with a very large focal length. The object I am imaging is several kilometers away.

The images do not have any exif metadata attached to them. When I run with no camera model overrides, the reconstruction is performed fairly well - the relative shape and camera position appear to agree well with predicted results. However, this does not produce accurate measurements in real-world units since the focal length is estimated much too low at ~0.92. Unfortunately, when I run with camera overrides (with the actual focal length), the reconstruction cannot be performed since there are no image pairs recognized.

I fear that some prior being used is starting the reconstructed camera position at an estimated distance of a few meters from the object, when the true camera position should be several kilometers from the object. Is there any prior I can override to provide an initial estimated camera position which is more accurate for my long focal length?