Threebeach 600mm

This lens consists of 2 groups 4 elements.


The distance from the front lens to the focal point is about 300mm, which is half of focal length. This design makes this lens small. But it causes strong chromatic aberration.


no filter


Violet fringe of chromatic aberration appears.



2015.1.2  Yosano Town in Kyoto Prefecture

Panasonic G5

I used a Y1 filter. Y1 filter cuts wave length shorter than 440 nm . It reduces violet fringe of achromat lens.

Y1フィルターを使ってみました。 Y1フィルターは、440nm以下の波長をカットします。これは、アクロマートレンズの紫色の色収差を低減します。

Automatic white balance setting of digital camera compensate yellow color.




2018.2.4  Kuwana City in Mie Prefecture

Panasonic G5

no filter


I made a paper aperture and put into this lens. It makes f15.

Violet fringe of chromatic aberration decreased.