Baader ACF DSLR Astro Conversion Filter - for Canon EOS 350D/10D/20D/30D

This filter replaces your Canon 20D's original internal filter, which blocks most of the red light from deep-sky nebulae. The Baader ACF filter allows this critical Hydrogen-alpha light to pass through, dramatically increasing your camera's sensitivity for astrophotography of emission nebulae.

Yes. After this modification, your camera's color balance will be strongly shifted toward red. While it's possible to correct this with a custom white balance, the camera is best considered a dedicated astronomy tool post-conversion. Autofocus with standard camera lenses may also be affected.

Simply removing the stock filter alters the camera's required back focus distance, making it impossible to reach infinity focus with many lenses and telescopes. The Baader ACF filter is a plane-parallel replacement that maintains the correct optical path length, ensuring sharp focus while also protecting the exposed CMOS sensor from dust.

You will see the most significant improvement on emission nebulae rich in Hydrogen-alpha. Expect stunning results on targets such as:

• The Orion Nebula (M42)
• The Lagoon Nebula (M8)
• The North American Nebula (NGC 7000)
• The California Nebula (NGC 1499)

The modification requires careful disassembly of your DSLR. While it is technically possible to reverse the process if you save the original filter, it is a delicate and complex procedure that carries a significant risk of damaging the camera. For this reason, it is generally considered a permanent modification.

It means the filter's surfaces are manufactured to be extremely flat and perfectly parallel to each other. This is a critical quality feature that prevents image degradation. It ensures the filter will not introduce any distortions or blur, preserving the full sharpness and resolution of your optical system.