One difficulty of taking multi-panel shots is how to ensure the size remains the same. This is one reason why I got the grid screen. However, it doesn't really help me here. :-P
In the 4R print, there is a slight hint of reflection off the background.
Also, did you notice the strong vertical barrel distortion? Looks like I need a macro lens after all. (Macro lenses are flat-field and have low distortion. Well, true macro lenses, anyway. ;-)
Lens Minolta AF 50mm f/1.4. Aperture f/8. Shutter speed 1/8. 2-sec MLU. On tripod.