Jump to content
Sign in to follow this  
wingeing Pom

Using Canon lenses for astro work

Recommended Posts

I have given misleading/incorrect information about using Canon lenses for astrophotography. If you look at the focus indicator window on a Canon lens, you will see at the infinity point a vertical bar (indicating infinity). At the bottom of this vertical bar is a horizontal bar off to the right. This bar indicates the amount of movement the lens has BEYOND INFINITY. So when connecting this lens to your camera you must use the correct back focus distance and you will find there is enough movement beyond the infinity point for FocusMax to do its stuff. If you operate the lens INSIDE the correct back focus distance in order to "free up" some movement beyond infinity, all you will do is increase the star FWHM values above what they should be at correct focus.


  • Like 1

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this