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LiveView Focusing

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#1 martinclayden

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Posted 18 October 2020 - 09:50 AM

Hi All,

 

I use Astro Photography Tool (APT) software to assist with collecting (mainly) DSO images. I use a Canon 77D DSLR,  APT (3.84)  and I'm attempting to use the camera Liveview function with APT to assist focusing (Lens Control function).

 

The problem is that even at ISO 25600 and simulated 30" exposure there's nothing to see to focus with via the APT LiveView display, yet a test shot at these settings shows plenty of stars on the downloaded image.

 

Is there a setting somewhere I've missed; perhaps something in relation to exposure simulation, is the sky simply too dark (although, having said that, 30" at ISO25,600 shows lots of stars!)

 

I'd appreciate any thoughts any one may have

 

TIA

 

Martin



#2 Boeglewatcher

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Posted 18 October 2020 - 10:06 AM

for my setup (f/7 scope w Canon 2000D), live view is too dark except for really bright objects like the planets or stars like Vega, etc down to Altair. I use a Bahtinov mask to focus w life view x10 mag at ISO 3200 (Vega, Deneb, Altair, etc.). for all other purpose like setting the right camera angle, etc. I do exposures, e.g. 10-20" at ISO 1600 or such.


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#3 martinclayden

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Posted 18 October 2020 - 10:16 AM

Boeglewatcher, thank you.

 

I do have the feeling that it's just too dark for LiveView. What I'm having some difficulty understanding is why, with Exposure Simulation active, LiveView is dark and captured images show lots of stars.

 

Just to be clear:

  LiveView, simulating 30" at ISO 25,600 = Dark

  Image taken at 30" and ISO 25,600 = Lots of stars

 

Regards

 

Martin



#4 Boeglewatcher

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Posted 18 October 2020 - 10:47 AM

Hi Martin,

i think Camera live view is Not helpful for taking Astro images. At least not for my cheap canon. The monitor needs to be switched off since it produces some heat and even life view when active for let’s say 30 sec when I am doing the focusing increases the camera temperature by some degrees. So, better to take short exposures with APT and align the camera in such way. I think life view of the Camera has its limitations when it comes to Astro photos.

cs Joachim 



#5 BrendanC

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Posted 18 October 2020 - 05:43 PM

I routinely use a really bright star now for focusing using Live View. I've got a plan set up in APT called simply Vega, all it does is Goto++ to that star so I can focus, using my Bahtinov mask with the Bahtinov Tool, then crack on with the rest of the session. 


Edited by BrendanC, 18 October 2020 - 05:45 PM.

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#6 17.5Dob

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Posted 18 October 2020 - 06:52 PM

Live View is pretty much worthless, except to get your focus "close" on a 1st mag star...

You'll still need to take some test shots to confirm.

AND...!!!! you need to continuously monitor your focus as ambient temps cool down...


Edited by 17.5Dob, 18 October 2020 - 06:53 PM.



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