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William Optics 48mm T-Mount for Nikon F
William Optics 48mm T-Mount for Nikon F
William Optics 48mm T-Mount for Nikon F

William Optics 48mm T-Mount for Nikon F

by William Optics
SKU WO-TM-NK-F-M48
$39.00 - $39.00
$39.00
$39.00 - $39.00
$39.00
Price Match Policy!
  • Connects M48 Accessories to Nikon F-Mount Cameras
  • Precisely machined 8.2 mm optical length achieves exact 55mm back focus when combined with camera
  • Female M48 x 0.75 Threads (Telescope Side)
  • Male Nikon F-Mount Bayonet (Camera Side)
  • Wide 48mm Aperture Prevents Vignetting
2 in stock
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • William Optics 48mm T-Mount for Nikon F

    The William Optics 48mm T-Mount for Nikon F provides a secure, direct connection from any M48 x 0.75 threaded accessory to a Nikon F-mount camera body. Consuming exactly 8.2 mm of optical path, it works seamlessly with your DSLR camera to achieve the standard 55 mm back focus for flat-field astrophotography.

    Precision Spacing: Built for Standard 55mm Back Focus

    Achieving the standard 55mm back focus distance required by most field flatteners and reducers demands exact component spacing. This William Optics T-Mount is engineered with an optical length of 8.2 mm, which combines directly with a Nikon F-mount DSLR's 46.5 mm flange distance to yield the required 55 mm total back focus (8.2 mm + 46.5 mm = 54.7 mm ~ 55 mm)—no additional spacers needed.

    By delivering the exact 55 mm optical path out of the box when attached to your camera, this adapter removes guesswork and eliminates potential spacing errors that can introduce field curvature or other aberrations.

    Secure Connection for Full-Frame Sensors: M48 Threading

    The adapter features female M48 x 0.75 threads on the telescope side, providing a wider and more robust connection than standard M42 T-rings. This larger diameter is essential for fully illuminating full-frame sensors without vignetting, ensuring the entire field receives even light from your corrector.

    A secure threaded connection prevents any flexure or tilt that can occur with less rigid adapters, preserving the precise optical alignment needed for sharp stars corner-to-corner. This rigidity is especially important when supporting the weight of a DSLR camera throughout a long imaging session.

  • How do I use the William Optics 48mm Nikon F T-Mount to achieve 55mm of back focus?

    This T-mount provides 8.2 mm of optical length. A standard Nikon F-mount DSLR has a flange-to-sensor distance of 46.5 mm. When combined, the total optical path is 8.2 mm + 46.5 mm = 54.7 mm (~55 mm). This delivers the required 55mm standard back focus directly from your corrector without requiring additional spacers.

    Why should I choose this M48 T-Mount over a standard M42 T-ring for my full-frame Nikon D850?

    The larger M48 (48mm) opening is critical for preventing vignetting on full-frame sensors like the one in the Nikon D850. A smaller M42 T-ring can act as an aperture stop, physically blocking light and darkening the corners of your images. This M48 adapter ensures your full-frame sensor is completely illuminated.

    Can I use this T-Mount to connect my Nikon D5600 to a William Optics RedCat 51?

    Yes, absolutely. The RedCat 51 has a native M48 thread on the back. This T-mount will connect directly to the telescope, allowing you to securely attach your Nikon D5600 (which uses the F-mount) at the correct 55mm back focus distance directly without any additional spacers or adapters.

    Will this William Optics M48 T-Mount work with my Nikon Z-series mirrorless camera?

    No, this adapter is designed specifically for the Nikon F-mount used on Nikon DSLR cameras. To connect an M48 thread to a Z-series camera, you would need a dedicated Nikon Z-mount T-adapter, or you could use this adapter in conjunction with a Nikon FTZ adapter.

    Does this William Optics T-mount have threads for 2" filters?

    No, this T-mount does not have internal threads for mounting filters inside it. Filters must be placed elsewhere in the optical train, such as in a dedicated filter drawer, filter wheel, or threaded onto the flattener/corrector itself.

    What is the thread pitch of the M48 connection on this T-Mount?

    The M48 threads use the standard astronomical pitch of 0.75mm (M48x0.75). This ensures compatibility with the vast majority of field flatteners, reducers, and other imaging accessories from William Optics and other manufacturers.

  • Telescope Side Connection M48 x 0.75 (Female)
    Camera Side Connection Nikon F-Mount Bayonet (Male)
    Optical Length 8.2 mm

    • William Optics 48mm T-Mount for Nikon F

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  • William Optics 2-Year Warranty