Canon EOS DSLR Camera Adapter with large 1.875" (47.6mm) diameter stainless steel bayonet. For 175TCC, 160TCC and 155TCC and all CCD Flatteners and all QUADTCC and Tri-TCC Telecompressor Correctors. (ADATCCEOS)

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This DSLR Camera Adapter for Canon EOS cameras with its large 1.875" (47.6 mm) inside diameter bayonet minimizes vignetting on full-frame sensors by eliminating the restrictive 1.5" (38 mm) diameter standard T-thread interface.

The adapter body is precision-machined aluminum and black-anodized. The bayonet is machined stainless steel, and both the body and the bayonet are baffled and painted flat-black on the inside.

The ADATCCEOS will place the camera sensor at the perfect 80.8 mm distance from the rear flange of the recommended back-focus spacer of the field flattener or TCC. Refer to the DSLR & Mirrorless Camera Systems diagrams below.

Warning: Be very careful if using filters with any of the TCC Telecompressor-Correctors, as they have very limited clearance to the back optical element. DO NOT stack multiple filters when using the TCC!

Designed for:


  • Net spacing distance: 1.45" (36.8mm)
  • Camera adapter: Canon DSLR bayonet
  • Female threads: 3.27 x 16tpi to use with the back-focus spacer specified for your field flattener or TCC.

Please note: this adapter can NOT be used with Canon manual-focus 35 mm cameras (series FD and earlier lenses).

Diagrams and Instructions

Refer to the following diagrams for additional information regarding spacing.

Current recommendations:

Legacy documents for your reference in case you own some of these components:

Custom Spacers & Adapters

If you need a spacer or adapter for a configuration that is not described above, we recommend that you contact PreciseParts. You may also review the following diagram that shows additional components you might find useful. Keep in mind that some are legacy parts: Field Flatteners, TCCs & QUADTCC Imaging Train Options

Astro-Physics 80.8mm Back-focus Spacing Distance

For more information regarding the concept for the 80.8mm back-focus spacing distance, refer to this webpage: Spacers & Extensions