Early anamorphic lenses breathe. If you shoot a project with them there are certain things you will come up against and it is undeniable that rack focusing has never been a strong point for vintage anamorphics. The design of the Lomo 2x Square Fronts is the root of the problem and the source of the beauty as well. You take the good with the bad.
The good is the wide aspect, the shallow DOF, the unique flares and the bad is breathing. Essentially, breathing is the slight appearance of the lens to zoom in and out while changing focal planes. As seen in the examples below the square fronts do suffer quite a bit but there are ways around the problem for the camera/post savy.
Lets start with the 35mm. In the first shot the focus is on the dollar bill and the color chart in the foreground. Take a look at the exit sign on the upper left side of the frame. As the focus shifts to the dummy in the background the FOV magically shifts.
This example is pretty easy to spot as the shift is so great. Will your average viewer notice? Maybe, maybe not but I bet if they don’t notice exactly what the issue is they will notice something is off if it is used repeatedly. The key is planning shots with this in mind and doing everything you can ahead of time to eliminate it.
Finally the 80. The background doesn’t provide as easy a target as the previous examples but if you look closely you can spot the shift occurring.