We occasionally receive requests expressing the desire to increase magnification with an extended working distance.

Typically, increasing magnification results in a shorter focal length.

Allow me to present options classified under the category of long-range types.


■ Long-Range (Extended Working Distance) Microscope (LRA Series)


Our extended working distance microscope not only incorporates a 10x zoom function but also achieves an extended working distance seamlessly.

The focal length can be adjusted freely within the range of 200 mm to 400 mm.


長距離(長作動)マイクロスコープ (LRAシリーズ)


(1) The field of view at maximum magnification when the focal length is set to 250 mm.


In the horizontal direction, it measures 6.7 mm, equivalent to an approximate magnification of 70 times.




高機能長距離ハイビジョン マイクロスコープ

High-performance Long-distance High-Definition Microscope (Stand type)




(2) Resolution at Maximum Magnification with a Focal Length Set to 250 mm


The resolution, as reflected by a glass scale used for resolution checks, is as follows.




(3) Advantages and Disadvantages


While the presence of a 10x zoom function and the ability to vary magnification at the same distance represent significant advantages, there is a slight reduction in resolution.

The field of view at maximum magnification with a focal length set to 250mm→400mm is as follows.





■ ƒ=75mm Fixed-Focus Lens Application


By adding a 2x rear converter and a 15mm close-up ring to a 75mm telephoto lens, it can serve as an alternative to the Long-Working Distance Microscope (LRA series).


f=75mm 固定焦点レンズの応用


(1) Field of View when the focal length is set to 250mm

Without a zoom function, once the focal length is decided, the magnification is determined. The horizontal field of view is 8mm, resulting in approximately 60x magnification.





(2) Resolution at maximum magnification when the focal length is set to 250mm


When projecting a glass scale for resolution checks, it appears as follows.





(3) Pros and Cons


While the focal length can be adjusted, once determined, it fixes the magnification as well. Without a zoom function, the lens has fewer elements, resulting in a brighter image and higher resolution compared to the aforementioned Long-Working Distance Microscope (LRA series).

In a direct comparison at maximum magnification, it slightly falls short compared to the Long-Working Distance Microscope (LRA series). The price is lower due to the absence of a zoom function.

When the focal length is set to 250mm→400mm, the field of view is as follows.





■ High-Resolution, High-Magnification Zoom Lens


There are specialized lenses with high resolution, high magnification, and zoom functionality available through our products. For more details, please inquire.

It is capable of achieving 420x magnification at a focal length of 200mm.