How to Choose your Lens

It is critical to consider the required conditions for your application which is key for choosing the correct
imaging devices. Common parameters and dimensions are shown. ( Refer to FIGURE 1)

Area sensor or Line sensor
Sensor size / Flange back
Lens mount / B・W or Color etc

Type of Lnes ( depend on application )
Fixed iris or adjustable
Fixed Mag or adjustable
Lens size etc

Type of light source
Lighting Method
Lighting WD etc

Vibration, Shock
Unnecessary Light
Dust, Water
Temperature, Humidity

Sensor Size

Sensor size = Pixel size (V) or (H) x Effective Pixel amount (V) or (H)

Pixel size: 4.4um x 4.4 um
Effective Pixel amount : 1600 x 1200
Sensor size(V) = 0.0044 x 1200 = 5.28mm
Sensor size(H) = 0.0044 x 1600 = 7.04mm
Sensor size = 7.04 x 5.28mm

Camera Mount

Each camera mount has a different size thread and flange back
(FB: distance from sensor to lens flange)
Common camera mount FB are shown below.

※1. FB size depends on the camera manufacturer.
You need to make sure both mount thread and FB are correct to get the correct image .
VST mainly offers C, F and M72 mount but also some special mounts for remote head cameras.
Please contact us for more details if you have a special lens mount.

Extension Tube

Tubes used between lens and camera when you need to focus in shorter WD than the lens
MOD( minimum object distance ).
FOV will be also smaller consequently.

SV-EXR series are available in 12 length type from 0.2mm to 50mm.

Rear Converter Lens

A optional lens used between lens and camera when you need to get higher magnification
( smaller FOV ) without changing WD.

SV-X series are from 1.5x to 5.0x.

Types of Machine Vision Lenses

Generally machine vision optics are classified into Macro lens for high magnification and CCTV or photographic lens for
infinity imaging.
Telecentric lens is categorized as macro lens. Most of maco lens is spacially designed for short working distance
( WD:10mm-500mm) to have high image quality in brightness, distortion, resolution in entire field of view (FOV).
Macro lens is often designed for specific WD without a focus adjustment and you need to set-up the camera position precisely.
The out line of machine vision lenses are shown as below Table.

Telecentric Lenses The chief ray is parallel to its optical axis.
Necessary for co-axial illumination
High measurement accuracy in height wise.
No perspective error in entire field.
Big in dimensions
Macro Lenses Specially designed for short working distance.Small distortion
Compact & Lightweight
Vibration resistance
Able to focus in a certain range only.
Limited FOV (magnification) range.
Fixed Focal Length LensesAble to focus infinity
Adjustable focus and iris
Wide range of FOV and WD
Low cost
Suitable for large FOV
Weak in vibration
Distortion in short WD
Line Scan LensesSpecially designed for long line sensor
Usually come with big camera mount
Small distortion and shading
Vibration resistance
Big in size
Heavy weight
Zoom Lenses Enable to change magnification without changing WD and camera position.Suitable for the application which need to change magnification frequently.Big in dimensions