Difference between revisions of "Camera Module Lens Modifcation"

Revision as of 13:25, 2 June 2013

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

Overview

Conversion

From	To
Revision 1.3 Camera Module Front	Modified Camera Lens

Parts Required

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

Tools Required.

1. 1mm Jewelers screwdriver
2. 4mm Jewelers screwdriver
3. Craft Knife
4. ESD mat and strap.

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

Turn the camera module over and pull the taps on the flexi connector to release the flexi, put the flexi in a safe place.
Gently prise the mini connector off the camera board.
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.
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'.
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
Place the body of the CCTV lens on top of the camera module, be careful to avoid touching the array. Note that the holes don't quite line up		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!
Fit the lens of your choice to the body and now your new camera is ready for focusing

Known Limitations

There is no Near Infra Red blocking filter in the completed assembly. This results in increased sensitivity by can result in a somewhat washed out colour image. Its possible to re-fit the original filter to the back of the lens using any suitable adhesive. However, the next stage of this project is to convert the camera to only operate in the Near Infra Red so this is not shown here.

Example image with no NIR filter fitted

Near Infra Red modification

The objective here is to make a reusable visible filter to allow easy waveband selection.

Parts Required

1. 10mm diameter visible filter [4]

Tools Required.

1. 1mm Jewelers screwdriver

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

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