Here it is and remember you saw it here first!
This is a head to head comparison of vignetting in a 40mm EP with the following binoviewers. The target is a daytime Moon. These images may not show the total vignetting but they show the relative vignetting in the different binoviewer units. The images were taken within a 20 minute span. The order of the images taken is listed below.
1. Burgess BV125C
2. Siebert 22mm BN
3. Burgess 24mm
4. Denkmeier with Dielectric coatings
5. Televue Bino Vue
This is through my William Optics 80mm short tube with the APO upgrade.
1. Burgess BV125C image attached