Singlestep

My mistake. distance should be incremented by 1m. So focus point is located 1m, bottom 2m and so on.

Actually answer by Awcine, May 30 2019 is more than enough. vertiacal or horizontal focal length have nothing to do with this oval bokeh. It's only the matter of compression ratio (squeez ratio?) change depending on the distance of the object. So to say your object in focus will be 2x squzeed while other object located after than focal length, say x2, will be squeezed by 4. Just imagine a rectangle, top width is 1m wide(sensor width), bottom width is 4m wide while the height is 4m.. Your object is located on 2m position. As the lens compresses and record all object in its angle objects in 4m distance will be recorded 1/4 width on the sensor, 8m distance 1//8 and so on... The final image will be de-squzeed only by x2 for focal distance object. Other object after the local length will not be restored it's original width. That's why the bokeh (a light source after the focal length) are not restored its origianl aspect ratio 1:1 but to remain half of recorded with.. A simple answer is that the light source which shows bokeh was not located with the object in focal length...