ML183A ML183M SL183A SL183M Ultra Wide No Distortion Varifocal Theia Lens 
Ultra wide, no barrel or fisheye distortion
Uses patented Linear Optical Technology®
1.8-3mm focal range, up to 116 degrees HFOV
5+ megapixel resolution
Near IR corrected - for multi-spectral and Day/Night
Slip ring for convenient orientation & positioning
EasyZoom™ requires minimal re-focus post zooming
For 1/2.3" sensor sizes or smaller
Overview SL183A ML183A SL183M ML183M
Iris type DC autoiris DC autoiris Manual iris Manual iris
Focal length 1.8 - 3.0mm 1.8 - 3.0mm 1.8 - 3.0mm 1.8 - 3.0mm
F/# F/1.8 F/1.8 F/1.8 F/1.8
Resolution 5MP 5MP 5MP 5MP
IR correction Yes Yes Yes Yes
Mount type CS-mount C-mount CS-mount C-mount
Lens Length to Mount 49.3 mm 44.3 mm 49.3 mm 44.3 mm
Lens Length (TTL) 61.8 mm 61.8 mm 61.8 mm 61.8 mm
Similar to Theia's other lenses, the SL183 and ML183 are high quality lenses 
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/ML183 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.
ML183A
1.8–3mm varifocal, ultra wide, no distortion, 5+ MPX, Day/Night, 1/2.3” 
format, DC auto iris, C mount
ML183M
1.8–3mm varifocal, ultra wide, no distortion, 5+ MPX, Day/Night, 1/2.3” 
format, Manual iris, C mount
SL183A
1.8–3mm varifocal, ultra wide, no distortion, 5+ MPX, Day/Night, 1/2.3” 
format, DC Auto-iris, CS mount
SL183M
1.8–3mm varifocal, ultra wide, no distortion, 5+ MPX, Day/Night, 1/2.3” 
format, Manual iris, CS mount
Accessories
KIT-9083
Part KIT-9083 Thumbscrew replacement kit for:
SL183M, SL183A
ML183M, ML183A
The kit includes 4x M2x5 set screws, 2x M2x5 button head screw and Allen keys.