# Entocentric Lens Calculator

We recommend trying our new Machine Vision Lens Calculator. It is easier to use, and will suggest specific lenses to consider.

Complete the fields below to calculate the focal length of the ideal lens.

Complete the fields below to calculate the aproximate working distance. (This is the distance between the lens and the object to be imaged.)

Complete the fields below To calculate the aproximate field of view (the area To be imaged.)

These lens calculators are for general-purpose entocentric lenses, the most commonly used type in machine vision installations. Our calculators support both area scan and line scan cameras of any resolution, any format, any pixel size, and any aspect ratio. Furthermore, you can specify an area-of-interest smaller than the camera's full resolution.

With the exception of lens focal length, the parameters you enter may be in any dimensional unit (mm, cm, inches, or whatever). The result will be in the same dimensional unit.
Lens focal length is always in mm.
First enter your application parameters in Calculator #1. This will help you determine the ideal lens focal length.
You're not likely to find a lens having the exact focal length suggested by Calculator #1. Therefore, you'll need to adjust the working distance and/or the field of view based on the focal lengths commonly available.
Using a common lens focal length, use Calculator #2 to determine the working distance necessary to get your desired field of view. Or, use Calculator #3 to determine the field of view resulting from a fixed working distance.
Lenses having focal lengths of 6, 8, 12, 16, 25, 35 and 50 mm are commonly available. Using a shorter focal length lens decreases your working distance and therefore captures more light, but the resulting image may have more distortion. A 16mm lens is often a good compromise.
Keep in mind that a smaller sensor size will increase the working distance.
Calculators assume field of view width is in direction of the camera sensor's width. If your field of view's height is greater than it's width, consider rotating the camera 90 degress.
For a line scan camera, enter a vertical pixel resolution of 1 to 3 pixels. You may then enter a vertical field of view of zero.
Having trouble finding a lens for a small field of view with a short working distance? Try our Macro Lens Calculator.
There are many other factors to consider beyond lens magnification. We'd be glad to help you select a lens appropriate for your project.