Jump to content

Canada's top-tier Telescopes & Accessories
Be as specific as possible when reporting issues and *ALWAYS* include the full version number of the application you are using and your exact *CAMERA MODEL*
NEVER POST YOUR KEY IN ANY PUBLIC FORUM, INCLUDING THE O'TELESCOPE SUPPORT FORUM ::: IF YOU DO YOUR KEY WILL BE DEACTIVATED WITHOUT NOTICE!
  • 0

Focus Problem - Frame and Focus


JTWaters

Question

What's the best way to focus my Canon 6D when no stars are displayed in 'Frame and Focus'?  There are no bright stars to focus on.  The lens are already set to infinity.  What's the ISO setting of the camera during Frame and Focus?

 

Jim

Phoenix, AZ

Link to comment
Share on other sites

  • Answers 5
  • Created
  • Last Reply

5 answers to this question

Recommended Posts

Jim,

 

The ISO setting is either what you have set it to be or the maximum value of the camera, depending on whether you have chosen to use "Maximum Sensitivity" setting.

 

With many lenses, infinite focus is not at the end of the focuser travel. It is back from it a bit.

 

The small size of the stars with a short focal length lens and the short exposure of LiveView frames make it very difficult, if not impossible, to focus a lens with LiveView. I would suggest taking short Snap exposures and use them to gauge how well you are focused. You can select a star and calculate the FWHM or HFD of it with short still frames, as well as with LiveView.

Link to comment
Share on other sites

In most cases, you'll need to forget the idea of Focusing on Dim Stars around your chosen DSO Target.

 

You should Slew to a Bright Star (but avoid any near the Horizon - and avoid any of the Hyper-Giant Stars like Beetlegeuse or any Close Binaries as all will make Focus Difficult), perform your Best Focus, and then Slew to your Target for Framing.  THis will also give you the best chance of Framing using the Dimer but now In-Focus Stars of your Target FOV.

 

And Don't Forget:  Reset ISO to your desired Imaging ISO when returning to Imaging from Frame&Focus.

Link to comment
Share on other sites

Jim,

 

When using a camera lens, instead of a telescope, you may have a problem even seeing a very bright star in LiveView.

 

Also, BYE and the Canon SDK allow you to change the exposure and ISO in LiveView. However neither of these affect the LiveView frame rate. So take short (5-10 second) snap images for focusing. This is the technique that you would have to use with a CCD camera. It works just fine. It is however somewhat slower than using LiveView.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.


×
×
  • Create New...

Important Information

This site uses cookies to offer your a better browsing experience. You can adjust your cookie settings. By closing this banner, scrolling this page, clicking a link or continuing to browse otherwise, you agree to the use of cookies, our Privacy Policy, and our Terms of Use