# Basic Lens Calculator

The calculators below will help you determine the lens focal length you need. It is assumed the camera's sensor has a 4:3 aspect ratio, the sensor is a common size, and that you will use all the pixels. For more advanced options, you'll find links to other calculators at our Lens Tech Center.

Browse our selection of lenses to find one that delivers the appropriate level of performance. Or, contact us for a recommendation.

These lens calculators are for general purpose entocentric machine vision lenses. You can access more precise calculators for entocentric, telecentric and macro lenses via a link on the Resources tab of each camera product page. Browse our cameras here.

- 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.
- Calculators assume sensor has 4:3 aspect ratio.
- 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 will be more distorted. 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.
- There are many other factors to consider beyond lens focal length. We'd be glad to help you select a lens appropriate for your project.