10 LF=27:GOSUB 10000
20 PRINT"THIS PROGRAM CACULATES PHOTOGRAPHIC EXPOSURE"
30 PRINT
40 PRINT"WHEN USING A BELLOWS EXTENSION"
50 PRINT:PRINT:PRINT: PRINT:PRINT:PRINT
60 PRINT"THE FOLLOWING FORMULA IS USED:"
65 PRINT:PRINT:PRINT"EXPOSURE                      2                  2"
70 PRINT"INCREASE =    (BELLOWS LENGTH)  /  (FOCAL LENGTH)"
75 PRINT:PRINT"NOTE: ENTER LENGTHS IN LIKE UNITS"
80 PRINT:PRINT:PRINT:PRINT:PRINT
100 INPUT"FOCAL LENGTH OF LENS";FL
105 PRINT:PRINT
110 INPUT"   LENGTH OF BELLOWS";LB
112 PRINT:PRINT
114 INPUT"F STOP WITHOUT BELLOWS";F
115 PRINT:PRINT:PRINT:PRINT
120 PRINT"LENS FOCAL LENGTH = ";FL
130 PRINT"   BELLOWS LENGTH = ";LB
135 PRINT:PRINT
140 EI=(LB)^2/(FL)^2
150 PRINT"EXPOSURE MUST BE INCREASED BY A FACTOR OF ";EI
151 N1=(EI^.5)
152 PRINT:PRINT"OPEN LENS "N1" F STOPS"
155 PRINT:PRINT
600 PRINT
610 PRINT"F STOP WITHOUT BELLOWS = ";F
620 PRINT
632 N=F/N1
635 PRINT"   F STOP WITH BELLOWS = ";N
640 PRINT:PRINT
700 LF=5:GOSUB 10000
800 PRINT"IF IT IS NOT POSSIBLE TO OPEN THE LENS, "
810 PRINT"MULTIPLY TIME BY";EI
900 PRINT:PRINT"HIT ANY KEY TO DO AGAIN / HIT E TO END"
1000 D$=INPUT$(1)
1010 IF D$="E" OR  D$="e" GOTO 9999 ELSE PRINT: GOTO 100
9999 STOP
10000 X=1
10005 X=X+1
10010 IF X > LF THEN  RETURN
10020 PRINT:GOTO 10005
$="e" GOTO 9999 ELSE PRINT: GOTO 100
9999 STOP
10000 X=1
10005 X=X+1
10010 IF X > LF THEN  RET