The Baader Planetarium Protective T-ring adapter for Canon EF mounts is an ultra-precise T2 ring which minimizes unwanted movement inherent in the low-tolerance bayonet mounts found on inexpensive T-rings.
The protective T-ring can be used to keep dust out of your Canon DSLR body and away from the sensor. However they are most useful when shooting through a filter, and strict adherence to the focal plane distance is required. Scopes such as Celestron's EdgeHD, and other scopes with built-in field flatteners have a sweet spot where the correction is optimal.
When used with unmounted filters, the height profile of the T-ring is identical to other T-rings on the market. When used with Baader low-profile filter cells, the T-ring is only 0.3mm taller, which is negligible.
The protective T-ring accepts 50.8mm and 50.4m unmounted filter glass, as well as filters mounted in low-profile 50.8mm (2") filter cells with a maximum height of 6mm (not including filter threads). A Delrin temperature compensation ring is included to protect unmounted filter glass from damage caused by high temperatures.
The largest possible clear aperture of 47.3mm (1.86") is achieved using the M48 adapter ring, providing exposures free from vignetting with extremely short focal length scopes.
A Baader Planetarium 7nm Hydrogen Alpha (Hα) filter is included with this product.
Three mounting adapters are included for maximum connectivity potential.
Additional adapters may be required to complete the connection to telescopes, spotting scopes and microscopes. If you're not sure, ask us.
Note: This product is also available with clear, UV-IR blocker or UHC-S filters, or without a filter.