A119 Pro Lens Modification

Decided to replace my A119 Pro original F1.8 Aperture uncoated Lens with narrow Field of View F1.6 Aperture coated Lens from A129 which can be ordered separately. The original Lens module has plastic base which I discarded favoring the metal base with better thermal dynamic resistance to focus drift in high heat. The plastic mount uses coarse screws while metal base uses fine thread screws. Both Lenses and Bases use the same Lens thread size and are interchangeable. The original Lens was glued to threads and circuit board but can be softened with hot air blower then pried off with needle. Once both screws were removed plastic base lifted from board without using heat or removing the glue.
The Aptina AR0521 5-MegaPixel Image Sensor circuit board was reused for this modification. Before removing Lens Base note the spacing along the white outline. My original base was aligned tight against the top 5 surface mounted components which was my concern. The two screws were extremely snug. Since the A119 Pro is 1440p you can't change the Sensor board.
Changing Lens obviously requires re-focusing and alignment. The process can be tedious and delicate. The shortest method is to assemble the Dashcam but without the plastic Len shell so you can hold the ribbon cable attached Lens in one hand and turn the outer Lens ring with the other as shown in this old A119S re-focus video. Lens Re-Focus Then connect external monitor to 4-pole AV-out port but its only VGA 480p resolution. Otherwise use the 2inch screen to find best focus then mark that position using white paint or similar as the center/start position. Power on and record fine adjustments at 0.5mm increments + or - from marked center line. Good idea to disable screensaver and review footage on computer to determine best focus position.
Alignment on some sensors can be an issue if image is blurry only on one side or bottom. Loosen the two base screws slightly and align base to limit of shift one direction at a time, keep base from touching surface components.

Conclusion: My original Lens suffered from bottom blur. The improvement of new Lens and metal base was instant and very noticeable. The time and effort invested in this DIY Project was well worth it. I'm not sure Viofo will sell this specific Lens and Sensor combination but they should. If you own the A119 Pro and unhappy with focus or alignment you now have an option.