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Focal Length Required Calculator

A commonly asked question is how to know what focal length lens is required to fill the frame with a subject of a given size at a particular distance, and there are many useful tools available which can calculate this. However, actually filling a frame entirely with a subject is not all that common. The tool provided here adds the option to select what percentage of the frame should be filled by the subject, and sample images are displayed illustrating various frame fill ratios. (The sample images all demonstrate the fill percentage vertically, but that should be sufficient to make a judgement as to how a horizontal subject will fill the frame in that orientation. Click on an example image to see a larger version of each one in a new tab/window.)

Manual Sensor Size
   Sensor size : mm
Select Camera
Maker :
Body/Model :
Sensor long side Sensor short side
Subject size   mm : in : feet : metres
Distance to subject   feet : metres
Frame filled   %


100% frame fill
100% fill
  95% frame fill
95% fill
  90% frame fill
90% fill
  85% frame fill
85% fill
  80% frame fill
80% fill
75% frame fill
75% fill
  70% frame fill
70% fill
  60% frame fill
60% fill
  50% frame fill
50% fill
  40% frame fill
40% fill


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