Theia's Lens Calculator App is a tool for iPhone and Android smartphones that allows a user to input camera distance, resolution, lens choice, and/or field of view needed then calculates image resolution and shows a sample image at that resolution to help the user understand what level of detail can be seen. All from the convenience of a mobile device on location. The app' is available for $4.99 on the Android marketplace and on iTunes. Visit www.TheiaTech.com/calculator.php to learn more.
Android
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
iPhone
The lens calculator app for iPhone/ iTouch is now available. Search for Theia in iTunes and download the app to your mobile phone.
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.
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