With Optics there are always trade offs.  
The Evetar [[m12_5.4mm_f2.0|M12 5.4mm f2.0 lens]] is a low distortion 10MP lens.  This produces a sharp high resolution image with a relatively good DOF - depth of field.  The DOF is the range within which an object remains in focus as it moves closer of further away from lens.
The Evetar [[m12_5.5mm_f1.8|M12 5.5mm f1.8 lens]] is a low distortion MP lens.   

//f// or //f-stop// represents the size of the aperture - the amount of the light entering the lens.  The higher the //f-stop// the more light.  

There is an inverse correlation between the //f-stop// and the DOF.  The higher the //f-stop// the shallower the DOF.  

For the SUB2r 4K/1080p camera board we selected the [[m12_5.4mm_f2.0|5.4mm f2.0]] for it's exceptional image quality.  This lens requires good lighting conditions and in some environments it will be necessary to  supplement the environment with additional lighting.

The optional [[m12_5.5mm_f1.8|M12 5.5mm f1.8 lens]] collects and delivers 23.4% more light to the image sensor than the [[m12_5.4mm_f2.0|f2.0]].  This lens works well in lower light environments.  Image quality can be enhanced post the sensor by increasing sharpness, but this can induce artifacts when the image is compressed.  There is also a slight reduction in the DOF. 

Picking the right lens for your application is key to an exceptional video image.

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