Nikon Apo Nikkor 480mm F9

[Darryl Roberts]

Do you know the image circle of the Nikon Apo Nikkor 480mm F 9, or if it will cover 11x14?

Advanced thank you.

 

[Ian C]

The data sheet is here.

Apo-Nikkor.pdf (savazzi.net)

It indicates an angle of view of 46° for the 480/9 APO Nikkor.

The diameter of the infinity-focus image circle of a lens is

IC = 2f*tan(θ/2)

where θ is the lens’s given angle of view in degrees. For the 480/9 APO Nikkor, the image circle at infinity is

IC = 2*480 mm*tan(46°/2) = 407.5 mm. The diagonal of an 11” x 14” film is about 452 mm, so it won’t fully cover at infinity.

For the 610/9 APO Nikkor,

IC = 2*610 mm*(tan46°/2) = 517.9 mm. This is the shortest 46° AOV lens in the series that will fully cover an 11” x 14” film at infinity.

Note: The image circles given on the data sheet are at 1:1 magnification with the lens's second nodal point two focal lengths from the image plane.

 

[Darryl Roberts]

Newbie question, Infinity is when my bellows would be at 480mm? But if I extend it, will it then cover? Thank you.

 

[Ian C]

Correct. At infinity the distance from the second nodal point of the lens is one focal length from the image plane.

The image circle will expand to 452 mm when the image distance (second nodal point of the lens to the image) is 532.4 mm. That happens when the lens is moved forward 52.4 mm forward from its infinity-focus position).

At that point the focused subject distance is 4875 mm or 4.87 meters. The magnification is 0.109 X.

 

[Darryl Roberts]

Thank you, I intend to use this with head/shoulder portraits.