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William Optics 48mm T-Mount for Pentax K - Black
William Optics 48mm T-Mount for Pentax K - Black
William Optics 48mm T-Mount for Pentax K - Black
William Optics 48mm T-Mount for Pentax K - Black

William Optics 48mm T-Mount for Pentax K - Black

by William Optics
SKU WO-TM-PT-K-M48
Save 5% Save 5%
$39.00 USD
$39.00 USD - $39.00 USD
$39.00 USD
$37.05 USD
$37.05 USD - $37.05 USD
$37.05 USD
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  • Connects Pentax K-Mount Cameras to M48 Accessories
  • Precisely machined 9.3 mm optical length achieves exact 55mm back focus when combined with camera
  • M48 (Female) Thread for Wide-Field Correctors and Reducers
  • Durable, Black Anodized Aluminum Construction
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • William Optics 48mm T-Mount for Pentax K - Black

    The William Optics 48mm T-Mount for Pentax K cameras provides a secure, direct-thread connection to modern flatteners and reducers. Consuming exactly 9.3 mm of optical path, it works seamlessly with your camera body to achieve the standard 55 mm back focus for flat-field astrophotography.

    Precision Spacing: Built for Standard 55mm Back Focus

    This T-mount directly connects your Pentax K camera body to any accessory with a male M48x0.75 thread, the standard for full-frame-capable field flatteners and reducers. The adapter's fixed 9.3 mm optical length combines directly with a Pentax K camera's ~45.5 mm flange focal distance to yield the required 55 mm total back focus (9.3 mm + 45.5 mm = 54.8 mm ~ 55 mm) directly—no additional spacers required.

    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 optical aberrations.

    • Wide M48 Aperture: The larger 48mm diameter helps prevent vignetting on larger camera sensors compared to standard 42mm T-rings, ensuring more even illumination across the frame.
    • Rigid Threaded Connection: By threading directly onto your corrector, this T-mount creates a solid, flex-free connection that is essential for maintaining optical alignment throughout a long imaging session.
    • Durable Construction: Machined from black anodized aluminum, the adapter is built to withstand repeated use in the field while minimizing stray light reflections within your optical train.

  • What is the William Optics 48mm T-Mount for Pentax K used for?

    This T-mount allows you to securely attach a Pentax K-mount camera to a field flattener, focal reducer, or other imaging accessory with male M48x0.75 threads, establishing the standard 55 mm total back focus required for flat-field astrophotography without needing extra spacers.

    How does the 9.3mm optical length of this T-Mount achieve 55mm back focus?

    When combined with a Pentax K-mount camera body (which has a ~45.5 mm flange focal distance), the adapter's 9.3 mm optical length brings the total system distance to 54.8 mm (~55 mm) directly from your M48-threaded corrector without requiring additional spacers.

    Why should I use this William Optics M48 T-Mount instead of a standard M42 T-ring?

    An M48 T-Mount provides a wider clear aperture than a standard M42 T-ring. This is critical for preventing vignetting (darkening of the corners) when using cameras with larger sensors, such as full-frame or APS-C models, ensuring your entire sensor is evenly illuminated by the telescope's optics.

    Will this T-Mount work with my William Optics RedCat 51 and Pentax K-1 camera?

    It threads onto a male M48 thread, and its 9.3 mm optical length plus the Pentax K flange distance (45.46 mm) gives about 54.8 mm. Check the RedCat 51's rear thread and required back focus in its manual before relying on it without spacers.

    Is the William Optics T-Mount compatible with all Pentax K-mount cameras?

    Yes, this T-mount is designed to be compatible with any camera that uses the Pentax K bayonet mount, including both modern DSLRs (like the K-1, K-3, K-70) and older film cameras.

    Does this William Optics T-mount include a filter holder?

    No, this is a simple mechanical adapter. It does not have threads or a slot to accommodate filters. If you need to use filters, they must be placed elsewhere in your imaging train, such as in a separate filter drawer or filter wheel placed before the T-mount.

  • Light-In Side M48 (female)
    Light-Out Side Pentax K Camera Mount
    Optical Length 9.3 mm
    Kind T-mount (camera adapter)
    Telescope-Side Connection M48x0.75 female
    Camera-Side Connection Pentax K bayonet

    • William Optics 48mm T-Mount for Pentax K - Black

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  • William Optics 2-Year Warranty