The Takahashi FC-100DF apochromatic refractor is designed around a fluorite doublet at F/7.4. It is equipped with a 50.8 mm rack-and-pinion focuser, larger than that of the FC-100DC, allowing the mounting of heavier cameras. Its use remains very versatile and even a small mount will make it possible to exploit its full potential.

If you want to make astrophotography at the native focal length of the refractor, a field corrector is available. It can also be equipped with a focal reducer : either the 76D-RD model normally intended for the small focuser, or the FC-35RD model, specific to the FC-100DF and its 50.8 mm focuser. The use of the latter is recommended for cameras or APNs equipped with APS-C or higher sensors.