BORG 107FL F3.9ED with Pentax 645Z & PhaseOne

A new reducer has been designed to cover the cropped 645 format. So I rented Pentax 645Z and tested to see last night.

I can’t publish the image result at this moment, without the permission from BORG. I’m sure I can do soon after their spring break will be over. But I can’t stand sharing with you here right now.  In short, this optical system is the best ever in BORG history and should be considered at the top of line in its class optically and mechanically. Spherical aberration is well corrected. So star edge is very clean, virtually no false color. The distortion at each corner of 645 sensor is very minimal. Astigmatism at Sagittal and meridional are minimal and both nearly even. So star looks crossing, not bad at all. Illumination looks plenty enough entire the sensor.  90FL should be flatter illumination. I will see tonight. Keep in mind, I’m talking about entire 55mm image circle. Full frame? guess what.

This image result encouraged me to try with further large sensor. It’s not realistic for myself though. Fortunately I will have meeting with PhaseOne in Denmark end of this month. Their sensor is 67mm diagonal. At the viewpoint from last night result, I’m hoping the scope might somehow handle with their sensor for daytime landscape application. Let’s see. After coming back from my European tour, I will show the testing report at their head office. (My wife – Mia is very excited to visit to Denmark for different purpose…..) I plan to go around each my partner in northern part of Europe this time. The southern area will be next year.

Here is their camera. I look forward to test BORG and their camera over there.


BTW, I noticed I didn’t show up new ED reducer itself yet. BORG proprietary 4-element optical design.



~ by tedishikawa on May 4, 2018.

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