Camera Module Lens Modifcation

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The purpose of this project is to replace the stock lens assembly of the Raspberry Pi Camera Module with a larger lens. The aim is to increase the be able to fit other lenses and filters in order to modify the field of view and waveband of operation.

Contents

Overview

Conversion
From To
Revision 1.3 Camera Module Front
Modified Camera Lens

Parts Required

  1. Raspberry Pi Camera Module [1]
  2. any 1/3rd inch CCTV camera lens [2]

Tools Required.

  1. 1mm Jewelers screwdriver
  2. 4mm Jewelers screwdriver
  3. Fine nosed pliers or good tweezers
  4. Craft Knife
  5. ESD mat and strap.
  6. 1mm single core wire

ESD Hazard

The Raspberry Pi camera module is a sensitive electronic component and will be suceptable to ESD [3]. Please take sensible precausions or you risk permanently damaging your camera.

Step by Step

Before you start you need to know if you want to remove the stock Infra-Red blocking filter in your camera or not. This should only be attempted if you need to access the near infra-red capabilities of yor RPi Camera module.

Turn the camera module over and pull the taps on the flexi connector to release the flexi, put the flexi in a safe place.
CloseUpRearCameraModuleRev1 3.jpg
Gently prise the mini connector off the camera board.
CameraModuleMiniConnector.jpg
CameraModuleDisconnectingMiniConnector2.jpg
Peal the lens assembly off the board, it only stuck on with an adhesive pad. The board and the lens should now be free. Put the board in a safe place taking care not to contaminate the adhesive pad, we are going to reuse it.
CameraModuleDisconnectingModule.jpg


Removal of the Basic Lens

Once you've removed the module from the camera board removing the lens is simply achieved using a pair of pliers to grip the threaded end of the lens and unscrew it anti-clockwise. Refit the module to the board and be sure to lightly screw the lens back into place to prevent any dust getting on to the filter.
Removal of the lens only, leave the blocking filter in place to protect the array.

Lens Mount Modification

Place the body of the CCTV lens on top of the camera module, be careful to avoid touching the array or getting dust into the module. The holes for the new housing don't quite line up but we'll fit that in a minute.
Notice the original module is easily covered by the 1/3rd inch housing.
Rear view shows the mounting holes don't quite match, shame its quite close!
The new lens body is too large and fouls the mini connector. Using a craft knife carefully waste away enough plastic to allow the body to sit flush over the connector.
Lens body fouls the connector
Try to make yours a bit neater!
Using the wire, thread a short length through the holes in the board and the lens body, twist the wire to secure the body to the board. Bend the wire up so it cant get trapped under the board and short something out! This is a temporary method of securing the lens housing. Once you're happy with the concentricity of the new housing to the array the body can be secured with any suitable adhesive.
CameraModuleReplacementConnectorFitWireWrapTie.jpg
CameraModuleReplacementConnectorFitWireWrapTieSide.jpg
Fit the lens of your choice to the body and now your new camera is ready for focusing. Don't Forget to remove the original lens with the tweezers otherwise you won't be able to focus the new lens!
CameraModuleReplacementConnectorFitWireWrapTieSide2.jpg
Fit the lens of your choice to the body and now your new camera is ready for focusing
CameraModuleReplacementConnectorFitWireWrapTieSide2.jpg
1/3rd" 16mm F1.2 Lens

Near Infra Red modification

Proceed as per the basic modifcation only remove the NIR filter as follows.

Take a fine bladed scredriver and work along the joint of the lens assembly, the idea is to gently dig through the plastic just above the metal base. This take a little time and patience and is considerably safer than using a knife! Once there's a gap between the parts use a larger bladed screwdriver to crack the seal and the lens assembly will 'pop off'.
CameraModuleUseAFinePointToWearTheModuleEdge.jpg
Salvage the lens assembly and store in a safe place, the filter will be of use later. Carefully handle the now bare camera array, refit this to the board. Its better to fit the mini connector first and let the regidity of the flexi re-align the array to the adhesive pad. Gently press the arry on to the pad avoid touching the array, use the edges only.
Red tint its the IR filter
Stock Lens assembly removed

Add a Visible Blocking Filter

This process modifies the lens cap from the 1/3rd inch lens to take a visible blocking filter [4]. The idea is to make a cap for the lens that can be fitted to temporarily turn any RPi module without a NIR blocking filter into an infra-red camera by blocking the visible light. Operation of a RPi Camera module with any filter will produce images with both colour and NIR content.

Using a small bladed screwdriver pierce the top of the plastic lens cap.
CameraModuleIRFilterFitModifyLensCap.jpg
Work around in a circle slightly smaller than the filter
CameraModuleIRFilterFitModifyLensCap2.jpg
Push out the middle
CameraModuleIRFilterFitModifyLensCap3.jpg
Lens Cap ready for filter
CameraModuleIRFilterFitModifyLensCap5.jpg
Press the filter in to the plastic, the plastic should be flexible enough to form around the filter.
CameraModuleIRFilterFitModifyLensCap6.jpg
Lens cap ready for fitting
CameraModuleIRFilterSide.jpg
Job done!
CameraModuleIRFilterFittedOverall.jpg

References

  1. RaspberryPi Camera Module
  2. 16mm F2.0 1/3" Replacement Board Lens for CCTV Camera
  3. Electrostatic discharge
  4. 10mm Visable blocking filter
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