BORG 1.08x & MASUYAMA 26mm

I’m using 7108 – 1.08x field flattener with 107FL these days. At beginning, this was only choice for 107FL until a dedicated reducer would be coming up. But now I’m willingly and pleasingly to use, Why? – speed and contrast.

This makes the speed at F6 when used with 107FL. So I was a bit hesitating before using. But I don’t feel the slow much. I feel like F5 or something around that. So I don’t mind pointing even to dim targets. Also I feel my image shows good contrast. The background seems to turn dark. I think speed and contrast are related each other. In short, It’s very good “Nukeh” in Japanese photographic term. Fortunately “Bokeh” is now used internationally. I was always hoping “Nukeh” should become international term too, because hard to describe the real meaning of “Nukeh”. It’s a kind of feeling unlike numerical data. I wonder if there is one word in English. It’s something like a mix of transparency, transmission, clean, natural and brightness. Carl Zeiss is often using the advertisement term like “shooting the atmosphere”. I think Nukeh is a kind of that.

Now I wonder why it’s good Nukeh. My analysis is

  • Cemented high quality elements – maximizing transmission and minimizing reflections
  • Lens curve design to avoid repeated reflections from the sensor.
  • Careful inside lens barrel finish – See a picture


This is multi-focal design between 300 and 800 mm. Also as shown below, 7425 allows to insert it into 2″ opening for non-BORG refractors.  So really universal design. If needed, M57 camera rotator can be set in front too. Very good value in my opinion.


I highly recommend 7108 as one of users. It completely covers full frame sensor. Flat illumination entire full frame makes creating flat easier too.

Finally one tip how to use properly. If you feel your image result is something wrong or not what you expected, check a thumbscrew back. Most likely it is over-tightened. Over-tightening stresses a lens barrel.  Don’t stress a lens and enjoy high contrast image!!

MASUYAMA 26mm is now available worldwide. It’s in stock at Agena too.

MOP-26Like other MASUYAMA eyepieces, looking beautiful coating!!


~ by tedishikawa on June 7, 2017.

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