Theia Technologies SY125A 1/2.5" 1.28mm F1.8 DC Auto-Iris CS-Mount Lens, 5 Megapixel Rated, IR Sensitivity, <3% Distortion

Typically 2-3 days
Current Stock:

Format: 1/2.5"

Focal Length: 1.28mm

Aperture: F1.8

Iris Type: DC Auto-Iris

Mount: CS-Mount


Additional Information

5 Megapixel Rated; IR Sensitivity (not IR Corrected); <3% Distortion; M.O.D. 0.5m.
This lens provides a horizontal angle of view of 135° when being used on a camera with 1/2.5" sensor size.

Note: Due to the type of distortion correction technology used for Theia lenses, the initial image output will be inverted.  This is corrected by either doing an image flip through the camera software or by physically inverting the camera.

Theia's 125 series lenses provide the widest field of view with low distortion available in the market. The lenses incorporate patented Linear Optical Technology® which allows an ultra wide field of view with low barrel distortion unlike other wide angle lenses that do not include Theia's technology. This rectilinear design allows increased resolution at the edges of the image thus increasing the probability of detection in security systems. The rectilinear design also eliminates the dewarping software requirement for many machine vision applications, improving MV system performance.

Similar to Theia's other lenses, the 125 series 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.

Although the 125 series of lenses is not IR corrected, it can be used on Day/Night cameras in some circumstances. If the camera is forced to Day-only mode or if there is no artificial IR illumination, the 125 series of lenses will work well.

Lens Field of view

Sensor Size
Sensor Diagonal
Sensor Format
Field of view (H)
109 °
125 °
135 °
Field of view (V)
93 °
109 °
119 °
Field of view (D)
122 °
137 °
141 °

Note: For 1/2.5" sensors, there may be some slightly dark corners depending on how well the sensor is aligned in the mount.


Lens Type:
1mm - 3mm
Megapixel Rating:
5 MP