I should add that my 35mm Ektagraphic AF-1 projector has the zoom lens which allows filling the 70x70-inch screen to its edges even with a reasonable projection distance. At one time I also had a Leitz Prado 6x6 projector (don't recall the lens focal length), and it required a fairly long projection distance to fill that screen, so had there been a zoom lens available for that projector it would have been a better choice. My point is that these factors should also be considered when seeking a 6x6 projector.