Theia's SL183 lenses provide ultra wide field of view without distortion. These are varifocal lenses allowing the user to optimize the field of view from wide angle to ultra wide. The lenses incorporate patented Linear Optical Technology® which allows an ultra wide field of view without barrel distortion unlike other wide angle lenses not including Theia's technology. This rectilinear design allows increased resolution at the edges of the image thus increasing the probability of detection.

Similar to Theia's other lenses, the SL183 is a high quality lens designed to allow the installer to take full advantage of the high resolution of HD and multi megapixel cameras. The lens can be used on cameras up to five megapixel resolution giving a crisp image from edge to edge.

In addition, the SL183 series includes EasyZoom™ which allows the installer to focus the lens once and then adjust zoom or magnification to give the optimized field of view. Only minor focus optimization is required after zooming. There is no need for the iterative focus-zoom-focus method of setup required for other varifocal lenses.

The lens is IR corrected for use with true Day/Night cameras. This IR correction focuses IR light from artificial illumination at the same plane as the visible light allowing the image to remain in focus when the Day/Night camera switches to night mode. Unlike lenses without IR correction, the night image will not be out of focus when using IR illumination.