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Any experience using astro autofocus software with DSLR lenses?

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#1 nathanm

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Posted 07 July 2020 - 02:43 PM

There are numerous software packages that will autofocus a telescope by taking photos and judging where the minimum size star disk is.   This includes Focus Max as a dedicated focus application, and/or features within telescope and camera control software like APT, NINA etc.

 

I use Canon DSLR - astro modified 5D Mark IV, and more recently a QHY 128c with Canon mount.   I use Canon and other Canon-mount lenses from 14mm to 200mm.

 

I already found that using a stepper motor with a Cine-style follow-focus gear on the lens can step much more finely than I can by hand.   I did this "manually" meaning I am still judging the spot size by eye.  But the stepper motor is much better than turning the ring.

 

But once I am there I thought hey, why not do autofocus with the same software that one uses for telescopes.

 

I believe the simplest way to do that is to get an ASCOM compatible controller for my stepper, like this https://pegasusastro...tor-controller/  and then use one of the many software approaches.

 

What is your experience doing this?   Is there any software that is particularly good in this case?  



#2 2ghouls

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Posted 07 July 2020 - 03:40 PM

https://sourceforge....focuserpro2diy/

 

For your Canon lenses mounted to your QHY 128C, this is the better solution though IMO: http://astromechanics.org/ascom.html



#3 nathanm

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Posted 07 July 2020 - 06:35 PM

The Astromechanics Canon lens interface is very interesting and I do use it with QHY.

 

That allows controlling the aperture, and also the focus motors if it is an autofocus lens.

 

However, most of the lenses that I use are NOT autofocus lenses.   They are manual - like Zeiss or Samyang/Rokinon.   So this approach does not help for them - that is why I use a cinema-style follow focus gear on the lens, engaged by a stepper motor.   Which can then be driven by a manual controller to bump focus by a tiny amount.   

 

My hope is that I can use it with astrophotography autofocus software.  Which in principle should work. 



#4 2ghouls

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Posted 07 July 2020 - 07:18 PM

Yes, I understand. The first link I provided is an Ascom driver for controlling a stepper motor through an arduino board that should work for you

Sent from my VOG-L29 using Tapatalk

#5 nathanm

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Posted 08 July 2020 - 12:02 AM

Thanks!



#6 Iamhondo

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Posted 08 July 2020 - 07:10 PM

...

 

I use Canon DSLR - astro modified 5D Mark IV, and more recently a QHY 128c with Canon mount.   I use Canon and other Canon-mount lenses from 14mm to 200mm.

 

...

You have several answers, but I'll throw in a couple more. 

 

First, tools like EOS Utility and Backyard EOS have the ability to adjust the focuser (via computer control) of a Canon EOS camera with a Canon lens. Neither does autofocus. Other programs interface to EOS DSLRs -- like APT. I don't know which if any will do autofocus for an EOS camera/lens combo. I think you have several references to an interface that would allow you to connect and focus a Canon lens with non-Canon cameras, like ZWO and QHY. Some tools can adjust aperture, too.

 

Second, I'm experimenting with the Tilta Nucleus-Nano wireless focuser. This is designed for film production, not astrophotos. I've mounted my ZWO camera with a Nikkor 180mm AIS lens. The focuser allows me to make micro adjustments using the hand controller, but not with a computer (afaict). That's not a huge drawback. Once I get precise focus on my lens, I lock that focus for the night.

 

Here's a short demo video of the Nano: https://www.youtube....h?v=CkOhuQYDYtw

 

HTH,

Joe



#7 nathanm

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Posted 11 July 2020 - 02:24 PM

I am currently using stepper motors designed for cinematographers similar in spirit to the Tilta Nucleas-Nano - they are just not wireless, and are controlled either with a hand controller, or via software on a PC, but not autofocus.

 

Basically what I want to do is use the cine-style steppers with an ASCOM driver and astro autofocus software.  I've been messaged by people who do similar things so I think it will work. 




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