Camera and Flash settings calculator for HP42S, DM42 and Plus42

Just to get used the new EQN feature of Thomas Okkens great Plus42, I entered two formualas into the equation editor, that may be of use to someone.

The first ("CAMERA") recalculates the missing value from any of the three given values (Light Value, ISO setting, f-stop or exposure time).

The second ("FLASH")recalculates the missing value from any of the three given values (Guide Number, ISO setting, f-stop or object distance).

To be able to run it on DM42 I also added a program version ready to be used by the solver.

 

Used variables:

CAMERA:

• LV: Light Value
• ISO: Camera ISO setting (... 50, 100, 200...)
• N: f-Stop (... 1.4 2, 2.8, 4, 5.6 ...)
• t: time in seconds (be sure to enter for example 1/125[s] as 0.008)

FLASH:

• GN: Guide Number of the flash at ISO 100  (ex. Nikon SB800 has GN=38)
• ISO: Camera ISO setting (... 50, 100, 200...)
• N: f-Stop (... 1.4 2, 2.8, 4, 5.6 ...)
• m: Object distance in meter (measured from the sensor)

 

Usage:

Use the solver on SwissMicros DM42, Free42 or HP 42S or CALC on the EQN menu on Plus42.

Plus42 equations:

CAMERA:2^(LV+(LN(ISO÷100)÷LN(2)))=(N^2)÷t
FLASH:GN×(SQRT(ISO÷100))=N×m

 

DM42, Free42 or HP 42S

00 { 107-Byte Prgm }
01▸LBL "CAMERA"
02 MVAR "LV"
03 MVAR "ISO"
04 MVAR "N"
05 MVAR "t"
06 RCL "N"
07 X↑2
08 RCL "t"
09 ÷
10 2
11 RCL "ISO"
12 100
13 ÷
14 LN
15 2
16 LN
17 ÷
18 RCL "LV"
19 +
20 Y↑X
21 -
22 RTN
23▸LBL "FLASH"
24 MVAR "GN"
25 MVAR "ISO"
26 MVAR "N"
27 MVAR "m"
28 RCL "N"
29 RCL "m"
30 ×
31 RCL "ISO"
32 100
33 ÷
34 SQRT
35 RCL "GN"
36 ×
37 -
38 RTN
39 END

 

Disclaimer:

This program is provided "as is" and "with all faults." I make no warranties of any kind concerning the safety, suitability, lack of viruses, inaccuracies, typographical errors, or other harmful components of this software.

 

Download:

Download the camera.raw file. The Plus42 equations can be pasted into the equation editor.