No.	Focus with Aldis Back Lens		Canera Extension at Infinity		Plate covered sharply at full aperture		Comments	Source
	Duo	Trio	Duo	Trio	Duo	Trio
	Ins,	Ins.	Ins.	Ins.	Ins.	Ins.
1	10		10 1/4		8 x 5			20
2	11 1/2	8 3/4	11 1/2	8	8 1/2 x 6 1/2	6 1/2 x 4 3/4		20
2a	12 3/4	9 3/4	12 1/4	8 3/4	10 x 8	7 x 5	For Series II to from F/12 with Duo and F/9 with Trio	20
3	14 1/2	11	14 1/2	10	11 x 9	8 1/2 x 6 1/2		20
4	17	13	17	12	12 x 10	10 x 8		20
6		9		8 1/2		6 1/2 x 4 3/4		20
6a		10		9 1/2		8 1/2 x 6 1/2		20
7	15	11 1/2	15 1/2	10 1/2	12 x 10	9 x 7	For Series III to form F/16.5 with Duo and F/11 with Trio	20
8	18		18 1/2		13 x 11			20
9	22		23		17 x 13			20