Why are 8 points needed to compute a fundamental matrix? Homograpies have 8 degrees of freedom.
Fundamental matrices have 7.
Essential matrices have 5.

To the best I could find, all those matrices are obtained by using the 8 point algorithm.

I don't see why the fundamental and essential matrices can't make do with less points.

Please enlighten me
Hum, no


A homography can be exactly fit to 4 point such that no three of them are collinear (example implementation in OpenCv).
An essential matrix can be fit to the image of 5 non-coplanar points (implementation).
A fundamental matrix can be fit to 7 points (implementation)