F Stop Distance Chart

For ISO/ASA 100 speed film only
Guide No. divided by f/Stop equals Distance 100 / 8 = 12.5 ft
Guide No. divided by Distance equals f/Stop 100 / 12. 5= f/ 8
For ISO/ASA other than 100 speed film
Guide No. times Film speed factor, divided by f/Stop equals Distance
Guide No. times Film speed factor, divided by Distance equals f/Stop
Increasing the ISO film speed by a factor of 4 will double the guide number
By Dwain Cox
Distance Conversion chart for Flash Guide No.
119
f/Stop 1 2 4 8 16 32 64 3.5 5.6 7
ISO/ASA
Factor
50 0.71
84.49 42.25 21.12 10.56 5.28 2.64 1.32 24.14 15.09 12.07
100 1
119.00 59.50 29.75 14.88 7.44 3.72 1.86 34.00 21.25 17.00
200 1.4
166.60 83.30 41.65 20.83 10.41 5.21 2.60 47.60 29.75 23.80
400 2
238.00 119.00 59.50 29.75 14.88 7.44 3.72 68.00 42.50 34.00
Distance Conversion chart for Flash Guide No.
100
f/Stop 1 2 4 8 16 32 64 3.5 5.6 7
ISO/ASA
Factor
50 0.71
71.00 35.50 17.75 8.88 4.44 2.22 1.11 20.29 12.68 10.14
100 1
100.00 50.00 25.00 12.50 6.25 3.13 1.56 28.57 17.86 14.29
200 1.4
140.00 70.00 35.00 17.50 8.75 4.38 2.19 40.00 25.00 20.00
400 2
200.00 100.00 50.00 25.00 12.50 6.25 3.13 57.14 35.71 28.57
Distance Conversion chart for Flash Guide No.
150
f/Stop 1 2 4 8 16 32 64 3.5 5.6 7
ISO/ASA
Factor
50 0.71
106.50 53.25 26.63 13.31 6.66 3.33 1.66 30.43 19.02 15.21
100 1
150.00 75.00 37.50 18.75 9.38 4.69 2.34 42.86 26.79 21.43
200 1.4
210.00 105.00 52.50 26.25 13.13 6.56 3.28 60.00 37.50 30.00
400 2
300.00 150.00 75.00 37.50 18.75 9.38 4.69 85.71 53.57 42.86
Distance Conversion chart for Flash Guide No.
200
f/Stop LOW 1 1.8 2 3.5 4 4.5 5.6 7 8 9
ISO/ASA
Factor
50 0.71
142.00 78.89 71.00 40.57 35.50 31.56 25.36 20.29 17.75 15.78
100 1
200.00 111.11 100.00 57.14 50.00 44.44 35.71 28.57 25.00 22.22
200 1.4
280.00 155.56 140.00 80.00 70.00 62.22 50.00 40.00 35.00 31.11
400 2
400.00 222.22 200.00 114.29 100.00 88.89 71.43 57.14 50.00 44.44
Chart 5
Distance Conversion chart for Flash Guide No.
200
f/Stop High 4.5 5.6 7 8 9 11 16 32 64 128
ISO/ASA
Factor
50 0.71
31.56 25.36 20.29 17.75 15.78 12.91 8.88 4.44 2.22 1.11
100 1
44.44 35.71 28.57 25.00 22.22 18.18 12.50 6.25 3.13 1.56
200 1.4
62.22 50.00 40.00 35.00 31.11 25.45 17.50 8.75 4.38 2.19
400 2
88.89 71.43 57.14 50.00 44.44 36.36 25.00 12.50 6.25 3.13
Flash unit Guide Number calculations
When film speed doubles, the guide number changes by a factor of 1.4
when film speed is halved, the guide number changes by a factor of 0.7
Page 1/1
Free Download

F Stop Distance Chart PDF

Favor this template? Just fancy it by voting!
  •  
  •  
  •  
  •  
  •  
(0 Votes)
0.0
Related Forms
  •  
  •  
  •  
  •  
  •  
1 Page(s) | 837 Views | 8 Downloads
  •  
  •  
  •  
  •  
  •  
2 Page(s) | 1050 Views | 11 Downloads
  •  
  •  
  •  
  •  
  •  
1 Page(s) | 524 Views | 2 Downloads
  •  
  •  
  •  
  •  
  •  
11 Page(s) | 4914 Views | 30 Downloads
  •  
  •  
  •  
  •  
  •  
12 Page(s) | 3105 Views | 18 Downloads