Focus Bracketer

Category: Electronics

| Year: 2023

Objectives

  • Automate the process of focus bracketing with a digital camera
    • Focus bracketing is taking multiple photos of the same subject with different depths of focus
      • These can then be combined in software to create a single photo entirely in focus
    • Some cameras have this feature built in, but mine does not
  • Require no permanent modifications to the camera and be easily removable 

Focus Bracketing Example

Single photo; the background is out of focus
Digital combination of five photos taken with the FocusBracketer; the whole photo is in focus

Process

  • Designed bracket to attach servo motor to camera, and 3D printed it
  • Created wheel for servo to turn the camera lens
    • Rubber grip is a length of audio cable glued to the wheel
  • Designed PCB in KiCad
    • Includes OLED screen and four buttons for the user interface
    • Has terminals to connect servo and camera shutter cables
    • Controlled by Seeduino XIAO microcontroller, programmed with Arduino framework
      • Chose this board because it can be soldered directly to the PCB, which keeps the device low profile 
      • Program allows user to set start point, end point, and number of steps
        • As start/end points are being set, the servo is jogged
  • Tested device by taking close-up photos of small objects

Reflection

  • The device generally works well
    • Sometimes the servo does not travel to the right place after the endpoint is set
      • This could be because the wheel is slipping
      • Measuring the rotation of the camera lens and providing feedback to the microcontroller could fix this 
    • Is much more efficient than moving the lens manually, and results in more consistent images
  • The process was a good test of my PCB milling skills
    • This was the largest PCB I had made in a while