Description

Designed to be used with: Current 2.7” Prime Focus Field Flatteners (67PF462, 67PF562 and 67PF582) and previous 2.7” and 4” Prime Focus Field Flatteners (67PF69, 67PF79 and S155EDFFF)

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. Since the introduction of Canon’s full 35 mm frame DSLR’s, people have been asking for a solution to the vignetting caused by the small clear aperture of the standard T-ring interface that is universally used to connect telescopes to DSLR cameras. This was especially true for Astro-Physics telescope owners who also had either our 2.7" or 4" Field Flatteners. What good were pinpoint stars to the edge of a wide field when the edge of that field was darkened by the T-ring’s vignetting effect? So, in keeping with our commitment to imagers, we introduced a solution!

The adapter body is precision-machined aluminum and is anodized black. The bayonet is machined stainless steel, and both the body and the bayonet are baffled and painted flat black on the inside. The adapter was developed to be used exclusively with 4" and 2.7" Astro-Physics Prime Focus Field Flatteners. (Please note that the Starfire 175EDF, 160EDF and 130GTX CCD Field Flatteners and Telecompressor Correctors have their own large diameter EOS Adapter, the ADATCCEOS). 

The 67RLEOS will position the chip (or film) at the correct distance from the Field Flattener optics for pinpoint stars.

A 48 mm internal thread allows the use of a filter in the optical path; however, double-stacking is not possible when used with a flattener.

The optical section of the 2" Advanced Convertible Barlow (BARADV), along with the 2" Barrel Extension w/ 48 mm Threads (A3703) can utilize these internal threads for a 2x magnification with central flat field (flattener not used) when used with an APS-C size sensor. This configuration requires using the 2.7" to 6x7 Outer Bayonet Adapter (ADA2767).

This adapter and the ADA2767, along with full frame Canon EOS DSLR's, can produce vignette-free, easily framed images with a wide variety of configurations.

This adapter has a net spacing distance of 1.67" (42.4 mm).

The spacing distance from the 48 mm internal threads (when using a BARADV or CCDT67) is 1.35" (34.4 mm).

Note: If you received your 2.7" Field Flattener prior to May 1994, you will need new aluminum parts to use this adapter. Please call Astro-Physics for details.