Although Baader officially calls this a T-ring, this bayonet offers far more. The Baader Protective T-Ring allows Canon EOS cameras to attach to standard 2” eyepiece holders. It is optimized for full-frame sensor cameras (such as the Canon EOS 5D), but can be used with any EOS camera. Since it has a wider clear aperture than the restrictive T-ring (42 mm) size, it does not vignette the light cone of fast optics.  Whereas it utilizes a 48 mm thread, it also includes a 48 mm to 42 mm adapter for using traditional T-thread accessories.

Baader has optimized the fit and tolerances between the camera bayonet and T-ring. This ensures that its connection to the EOS camera is wobble-free and has no lateral play, thus guaranteeing a stable image platform for long exposures.

One of the unique features of this “T-ring” is that it accepts internal filters (optional).  Baader unmounted 50.4 mm or 50.8 mm and Baader low-profile 2” mounted filters can be installed internally.

You may order this product without a filter or with a preinstalled filter for your convenience. You may purchase additional filters at a later date, if you wish. Choose the configuration that best suits your needs.

• Without any filter. You may purchase a filter separately at a later date.
• UV-IR filter preinstalled. Transmission curve at this link.
• UHC-S filter preinstalled. Transmission curve at this link.
• H-alpha filter preinstalled. Please note that using the H-alpha filter requires that the camera has been modified and its internal filter replaced with an expanded range filter. Modification is not needed for the Canon 20Da and 60Da cameras. Transmission curve at this link.

An additional benefit of these filters is to offer dust and moisture protection for your camera’s sensor.

Parts Included:

1. Protective T-Ring for CANON EOS body
2. Baader UV-IR, UHC-S or H-alpha filter (optional)
3. Temperature compensation ring (to prevent filter damage at high temperatures)
4. S52/M48 adapter ring (M48 corresponds to the international 2" Astro filter thread)
5. M48/T-2 insert ring
6. S52/2" Nosepiece (with additional 2" M48 filter thread on the front side)