Fluorite Flatfield Converter (FFC) / 3x-8x

Fluorite Flatfield Converter (FFC) / 3x-8x

Baader FFC – 2" / T-2 Fluorite Flatfield Converter

The CaF₂ Fluorite-Flatfield-Converter can be combined with every optical system for photography and visual observations as best and most sophisticated barlow lens in the world

• apochromatic, fully multi-coated lenses (note: w. multicoated Fluorite-lens faces
• Resolution in lines is 10x higher than that of the best projection eyepieces
• 90 mm image circle for medium format cameras

For almost 20 years (as well as 20 years ago already) our customers had asked again and again: "Do you have a barlow lens or projection eyepiece – but with a flat field – which can be used with medium format (6x7 Pentax) cameras for imaging sun, moon and planets, but without the typical loss of sharpness?"

This bothered us back in those times , and finally one of the designers of the Zeiss APQ lenses calculated the ultimate projection system with a flat image field in 1997. To actually make this design become reality, extreme types of glasses were needed. In this case, two multicoated fluorit-lenses - at that time and until today - a nightmare to produce.

The result was an optical system with an unmatched sharpness, with a ten times higher resolution of line pairs than a Zeiss Abbe eyepiece. Even so the days of emulsion film cameras are long gone, this lens system has persisted to be "the sharpest barlow ever made".

By changing the distance to the camera sensor, you can vary the magnification between 3x and 8x. The optimum line resolution is set at 4x magnification, then you have the full sharpness over an image circle of 90 mm diameter. On the axis, the sharpness is only limited by your telescope – even at a magnification factor of 15x. We have tested this at an AstroPhysics lens telescope. Slowly slowly even the large diffraction limited field of 90 mm will become of importance again - with the advent of ultrafast and giant CMOS-cameras covering a field of 70 mm in diameter.

The FFC can be connected onto every T-2 thread and its 2" main body likewise fits into every 2" eyepiece clamp. With the help of our Astro T2™-System and the M 68-System you can connect it onto a whole world of telescopes.

For best results, you need to keep a certain distance to the original focus point. Please take a look at the PDFs in the Dowmload-section for technical information