Motorized zoom lenses

Motorized Zoom / Focus / Iris lenses designed for larger image sensors kitted with motion controllers.

Introduction

Motorized zoom lens systems designed to be integrated into custom optical instruments and operated remotely. Lenses are paired with 4 axis custom motion controllers.

Index

Lens name Zoom ratio Focal length, mm Image circle, mm
L084 40x 6.3 ~ 252 9.2
L085 25x 5.3 ~ 130 6.8
L086 18x 6.8 ~ 120 9.2
L116 (TBD) 5x 10.5 ~ 47 9.2
L117 32x 6.5 ~ 212 9.2
L119 (TBD) 16x 16.8 ~ 269 20.8
L120 28x 6.7 ~ 190 9.3

Operation

Detailed SCE2-M controller documentation is located here. Information and examples below explains how to use lens functions.

Parameters

In order to function properly, controller has to be configured. There are many things that should be adjusted: max motor speed, direction, homing parameters, motor acceleration, motor steps per mm calibration and more. Mostly suitable parameter table is maintained along with source code on SCE2-SDK repository on GitHub. Most parameters can be updated during normal operation, but controller restart might be required. Motors are calibrated to match g-code travel value with physical motor travel length in mm.

Firmware has 2 startup command lines that are executed during power on sequence. Any G-code command can be used. However for smaller motors we recommend setting lower so motors will not overheat.

Iris

Iris (also known as aperture) is responsible for:

New lenses have 2 types of iris mechanisms;

Due to construction topology DC-Iris is always closed after controller is reset

Homing

Two interpretations of homing are used in lenses and controllers.

If standard firmware detects that limit switch is actuated it decides that it is dangerous situation and motors should be powered down. While for CNC this behavior is perfect it is not acceptable for lens control. It is pretty easy to configure controller to operate normally when limit switch is actuated. However if limit switch is already actuated homing procedure will fail. This functionality should be fixed in upcoming firmware updates. Meanwhile prior to homing procedure axes should be moved away from limit switches manually before performing homing procedure.

SDK

Source code of development kit is maintained on GitHub.

Lens Tester GUI

screenshot.png

Console demo

screenshot.png

L084-DEVKIT

Brief

L084 is 6.3-252mm focal length (40x) motorized zoom lens is designed for 1/1.8" image sensors, has zoom/focus/iris functions, designed for 8M sensors.

IMG_4791__w.jpg

Specifications

Optics

Image sensor 1/1.8" Effective image area > 9.2mm
Focal distance 6.3 ~ 252mm / ±5%
Aperture f/1.4 ~ f/5.0
Focus range
  • WIDE: 1.0m - infinity
  • TELE: 2.0m - infinity

Field of view (D=8.81mm)

  • WIDE: 73.0°
  • TELE: 1.9°

Distortion

  • WIDE: -4.09%
  • TELE: 2.89%

Recommended image sensor

IMX334
Bare lens weight 465g

Mechanics

Flange back (FB, see diagram below)

+0.93 (in glass t=0.3 IRCF)

Lens zoom structure The stepper motor is directly connected to the screw
Lens focusing structure The stepper motor is directly connected to the screw
Lens size
  • Length: 168.7mm
  • Width: 72.8mm
  • Height: 57mm
  • Front end diameter:  69.5mm

In order to accommodate different image sensors, the focal distance is set back by FB distance. The actual distance for a specific sensor has to be calculated and spacers used. If the image plane is not set correctly, focus irregularities in the projected picture are expected.

fb.png

Motor specifications

Screw pitch 0.4mm
Spiral rotation direction Right
Rated voltage 5.0 VDC
Coil resistance
  • Zoom1: 20Ω ± 10% / phase (T=25°C)
  • Zoom2: 20Ω ± 10% / phase (T=25°C)
  • Focus: 55Ω ± 10% / phase (T=25°C)
  • Iris: 35Ω ± 10% / phase (T=25°C)
Phase count 2
Step angle
  • Zoom1, Zoom2, Focus: 18° / step
  • Iris: 0.6° / step
Operating temperature range -30°C ~ +70°C

Position alignment sensor PI

Model number
  • Zoom1, Zoom2, Focus: RPI-222 ROHM
  • Iris: GP1S196HCZ0F SHARP

Iris

Blade count 10
Drive mode Stepper motor

IR switch

Coil resistance 22.5 ± 10% (T=20°C)
Operation voltage

4.5 ~ 5.0V

Current consumption

144 ~ 200mA

Filter thickness

0.3mm

Filter count

2

Switching time

200 ~ 500ms

Filters
  • Open air
  • 380 ~ 650nm (TAVG >90%)
  • BP780 (400~750nm TAVG >1%, 780~1100nm TAVG >90%)

Dimensions

L084-DEVKIT.PNG

Detailed 3D model is hosted on GitHub 3D models repository

More detailed documentation coming soon

L085-DEVKIT

Brief

L085 is 5.3-130mm focal length (25x) motorized zoom lens is designed for 1/2.7" image sensors, has zoom/focus/iris functions, designed for 5M sensors.