Camera Lens Calcluations

Q:How far away from my subject can I be and still fill the photo frame (top-to-bottom) with an image of the subject?
How tall is the subject you are going to photograph?	meters
A regular person might be 2.0 meters tall. A large bird around 0.6 meters.
What is the focal length of the lens?	millimeters
A telephoto lens might be from 200-500mm, portrait lenses typically range from 50-80mm. If you're using a zoom lens, enter the larger value of the lens range.
What is the vertical size of the image sensor in your camera?	millimeters
Traditional '35mm' film is 24mm tall. The photo sensor in the Nikon D70 digital camera is 15.6mm. See your camera's specifications for this value.
[view formula]
A: The maximum distance from the subject you are photographing is 4.22 meters.

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Q:At a certain distance, what percent of my image sensor (top-to-bottom) will the subject I am photographing occupy?
How tall is the subject you are going to photograph?	meters
A regular person might be 2.0 meters tall. A large bird around 0.6 meters.
What is the focal length of the lens?	millimeters
A telephoto lens might be from 200-500mm, portrait lenses typically range from 50-80mm. If you're using a zoom lens, enter the larger value of the lens range.
What is the distance between you and the subject you are going to photograph?	meters
Enter the distance in meters between you and the subject being photographed.
What is the vertical size of the image sensor in your camera?	millimeters
Traditional '35mm' film is 24mm tall. The photo sensor in the Nikon D70 digital camera is 15.6mm. See your camera's specifications for this value.
[view formula]
A: At a distance of 10 meters, the subject will occupy 41.88% of your image sensor (or 10.05mm). The magnification factor will be 0.005, meaning the lens must have a macro ratio (also called maximum mangifiation) of 1:199.0 or better in order to focus at this distance,which is almost always the case.

Other useful photography calculators can be found here.