Does anyone know if the Zeiss Biogon 21mm f2.8 ZM lens with the rectangular 21mm/25mm Lens Shade interfere with the rangefinder of a Bessa R4A or R4M? The Cameraquest site shows the Bessa rectangular LH-1 Lens Hood for the 21/4 will not work with the R4 cameras. I noticed that the Zeiss hood has the cutouts for the viewfinder while the Bessa hood does not. Is the wider view of the R4 the reason for this limitation?

Any help would be appreciated.