AFAIU Magento zoom spot size is defined via CSS (square by default). It takes a large product image and fits it in by the short side and then allows to zoom it to actual size.
So for example if I have a
200x200px spot and
900x3000px image I will only get a top square part of my image inside of the spot and the rest can be zoomed in.
Is there a chance to make it that Magento takes along side of an image for initial downsizing and displays its full length from the start filling it with white spaces to a square?