New Astro Filter – VR3XII & BORG 90FL F6

This should be the alternative good option for people who are hesitating to modify its own camera. The design concept is that the filter dramatically attenuates visual spectrum region while fully passing at Ha emission. Very unique optical design!! This is a completely opposite concept to the usual.  Yes, it requires longer exposure or higher ISO. But I don’t think it’s the big problem in today’s camera much. See preliminary data at


The above both were taken by a same camera (unmodified) in same sky, night and location. So it’s quite fair comparison.

Following red curves describe what the entire transmission is when VR3XII and a stocked camera are used same time. Df is the measured transmission curve of Nikon Df camera.  Canon is quite similar too.


Generally Fujifilm X camera has twice or more transmission at Ha than Nikon or Canon does if my understanding is correct. At least S3Pro was so. I don’t know current camera’s response curves are. But feel like still similar level in my experiences. So I’m expecting this filter will be good match with the stocked Fujifilm cameras. Let me see. I will test with my X-T1 when the marine layer goes out from my sky.

Following sizes will be are available soon.


Canon APS-C & full size

Nikon APS-C and full size


VR3XII-52, 52mm filter

Following is an another gorgeous image taken by Steven Bellavia with his BORG 90FL F6 configuration.



~ by tedishikawa on June 18, 2018.

3 Responses to “New Astro Filter – VR3XII & BORG 90FL F6”

  1. Ted, do you have any thoughts on how this filter would work with a Sony Alpha 99? Thanks!

    • Mike,

      Sony should be quite similar to Canon/Nikon. As far as I know, Fuji is only difference. Ted

  2. One more question, Ted. In addition to my Sony Alpha 99 I have a Canon 70d that I bought used with the intention of have it converted for astrophotography. Would you recommend doing that or buying this filter that I could use with both of my cameras, since one is full frame and one is APS-C?

    Thanks again,

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