***************************************************************
for 3 1/2 inch lens; CLOSEUP work, bellows extension and factor
***************************************************************

focus  lens-film  bellows    added stops   bellows-factor

inf       1 FL      3.5"          0              1
 21"      1.5       5.25"         1              2
  7"      2         7"            2              4    (1:1)
  5.25"   3        10.5"          3+             9
  4.6"    4        14"            4             16
  2.4"    5        17.5"          5-            25


***************************************************************
for 6 inch lens; CLOSEUP work	 bellows extension and factor
***************************************************************

focus  lens-film  bellows    added stops   bellows-factor

inf      1 FL      6"          0              1
 36"     1.5       9"          1              2
 12"     2        12"          2              4    (1:1) 
 10"              15"          2+             6.25  
  9"     3        18"          3+             9