illustra Lens Calculator
Theia's lens calculators (more accurately image resolution calculators) let you see what to expect from different lens-camera combinations. The pictures represent the field of view for a given camera-lens combination and the image resolution. You can use these pictures to set expectations for your customer about how far away a license plate can be read or what level of detail can be seen in a person's face.
Theia offers smart phone app versions as well as a free online version (see below). For the mobile app, the picture represents the image resolution you can expect from the camera and lens combination.

The lens calculator app is currently available for Android. It can be found by searching for "Theia" in the Android market place on your Android phone.


The lens calculator app for iPhone/ iTouch is now available. Search for Theia in iTunes and download the app to your mobile phone.

Free Online Version
Instructions: All input fields and drop-down menus in yellow are changeable. Green fields are results. Help
illustra Lens Calculator Settings Table
AD Model Max Resolution Sensor Size Lens Aspect Ratio
illustra 610 HD 1080p 1/2.7'' "Other Lens" 3-9mm or SL183 (model dependant) 16x9
illustra 600 HD 720 (1280x720) 1/2.7'' "Other Lens" 3-9mm or SL183 (model dependant) 16x9
illustra 400 2/3 MPix (896x720) 1/3'' "Other Lens" 3.3-12mm 5x4
Detailed Instructions
  • Step 1: Choose your camera resolution. The most common sensor size for that resolution is chosen automatically. If your camera has a different chip size, you may select it from the chip size drop-down menu. For larger sensor sizes, there may be some dark corners with Theia's lenses as they are designed to cover up to 1/2.5" sensors. A vertical cropping of the image can eliminate those dark corners.
  • Step 2: Choose the lens. Theia's lenses are listed as well as a general lens type. You may select from the list or enter the focal length or field of view directly into the appropriate boxes. For non-Theia lenses with field of view >60° you will get some curved barrel distortion in the image which is not shown in this calculator.
  • Step 3: Choose one of the input parameters: Distance to object, desired image resolution, or field of view. Only one of these three parameters is an independent variable. The other two parameters will be calculated based on the camera-lens combination you selected earlier.
  • Output: The parameters and representative images are calculated and displayed. Beware the overview picture doesn't change to reflect the object distance setting. Objects shown in the picture are at a fixed distance which was set when the picture was taken. This overview picture represents the width of the field of view, not the resloution you can expect.
  • Options: There are two optional drop-down menus. The "Application type" menu allows you to choose a representative picture for an application. There are indoor and outdoor application examples. The "Aspect ratio" menu changes the vertical field of view. This vertical field of view only makes sense when looking at a plane as it is the field of view in the plane at the set object distance.
  • Patents pending. If you have questions on the use or interpretation of this calculator, you may contact Theia Technologies at 503-570-3296.
With Theia's Linear Optical Technology® lenses, image resolution for objects along a plane (perpendicular to the camera) is constant even though the objects are farther away from the camera at the image edges. For instance, the person in the image center at 20 feet distance is 37 pixels/ft. At the edge of the image (SY110 lens in this case), the person is still 37 pixels/ft but they are 40 feet away from the camera. Other wide angle lenses will decrease image resolution as the object moves to the edge of the image. For more information, read about Theia's Linear Optical Technology®.
For technical support using these calculators, please contact Theia customer service.