This Article is about:
- Focusing Systems explained
Focusing Systems explained
There are three general focus systems that a Fluke Thermal Imager can have:
- Fixed Focus (focus free)
- Manual Focus (standard focus and advanced manual focus)
- Automatic Focus (LaserSharp autofocus)
Focus-free
A Camera with focus-free optics is designed in such a way that while the camera is focused at one distance, it delivers the image in focus for a broad range of distances. The best result is delivered at the distance, at which the camera is focused but the image is still sharp from half of its distance up to several times of the focus distance.
Many focus-free cameras are focused at about 1m, delivering image in focus from about 0.5m up to several meters, with the best results achieved at 1m distance.
Cameras with a manual focus allow to get the image in focus in the full range of distances at which the camera can be focused. For Fluke cameras, a minimum distance for manual focus is 15cm.
When the camera has a combination of both, focus free and manual focus, it means you can chose either way and get a sharp image from 15cm or set the fixed focus and get a sharp image from 0.5m to several meters.
The camera models, which have focus-free optical system: PTi120, TiS20+, TiS20+ Max, TiS60+.
The camera models which provide both manual focus capability, and have the focus-free position are TiS55+ and TiS75+.
Manual focus
With Fluke cameras you can find two types of manual focus systems.
A simple mechanical focus system is available in the basic cameras with manual focus. With this system the focusing distance of the camera is adjusted by rotating the focus wheel on the camera, which physically moves the camera lens to adjust focus. When you use such focus system, the rotation of the focusing wheel is limited by the physical range of the lens movement. You cannot move the focusing wheel anymore, when the lens achieves the limits of its movement. Applying too much force when the focusing wheel stops may damage the camera.
A simple mechanical focus system you can find in the TiS55+ and the TiS75+ cameras. With previous generation camera models you can find such focusing with the TiS45, TiS55, TiS65 and TiS75 cameras.
An advanced manual focus uses the complex electromechanical system system to adjust the position of the lens. Advanced manual focus is usually found in the cameras with autofocus capabilities, as the camera should provide both possibility to adjust focus manually and autofocusing. In such a system the focusing wheel is an electronic encoder, which sends the signals to the focusing motor to move lens forward or back depending on the direction of the focusing wheel rotation. When the lens achieves the limits of its movement, it stops. But you still can rotate the focusing wheel, it simply will not make any effect on the image.
The advantage of this system is that you never can damage the focusing system by applying excessive force to rotate the focusing wheel, as the focusing wheel can rotate in both directions indefinitely.
The advanced manual focus you can find in the following camera models: Ti300+, Ti401Pro, Ti480Pro, TiX501, TiX580.
Autofocus
The automatic focus system will set the focus for you automatically at any given distance.
There are different approaches to provide autofocus for thermal cameras. Fluke introduced autofocus system based on use of built-in laser range finder, which measures exact distance to the target and provides this information to the camera focusing system for precise focusing. This system got a market name LaserSharp® autofocus.
For the user it works in the following way:
First, press the secondary black trigger to activate the laser.
Then select a target with the laser point.
Once the laser point is at the correct target, release the trigger. The camera will focus at the distance to the point selected with the laser. The focusing takes less than 1 second.
LaserSharp® autofocus you can find within the same camera models, which have advanced manual focus.
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Focus-Free
(Fixed focus)
camera
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Manual focus camera | Focus-Free position marked on manual focus camera | Camera with advanced manual focus and LaserSharp® autofocus |