Taking flat frames with a Canon EOSS R


Kevin Dixon
 

Good Morning folks,

I have begun to use my new Canon EOS R for astrophotography.  Images to date have been wonderful.  However, the raw images would definitely benefit from the use of flat frames.  I am quire familiar with shooting flat frames with a CCD camera but have no idea as to how to shoot flats for the Canon EOS R.  I am hopeful that you might offer up the procedure that you use to acquire effective flat frames for a camera like the EOS R.

Thanking you in advance.

Clear skies,
Kevin Dixon


John Schnupp
 

Kevin,

The purpose of flats is the same no matter the camera type, so the procedure is approximately the same.  I usually try and get a histogram that is centered about half way.  Needs to be exposed enough to show the fainter dust bunnies and donuts, but not so much that there is saturation.  Start with and evenly illuminated image field.  Two common ways are illuminated panel or sky flats with a t-shirt.

On a dedicated astrophotography camera [true CCD are rapidly being replaced by CMOS, the terms CCD and CMOS are more about the semiconductor manufacturing technology used, which is a whole other discussion] the exposure is totally manual.  That is to say, you at the operator, need to pick the correct exposure time to get the histogram to the desired position.

Depending on how you are using your DSLR there may be two different scenarios. 
1. DSLR is attached to a scope.  On a scope the aperture is fixed.  Use any of the automatic modes so that the camera automatically chooses the correct exposure time.
2. DSLR is attached to a compatible lens.  Using a lens will usually allow control of the aperture.  In this case use the Av mode and make sure the aperture is set to the same aperture as your light frames. 
Then set the DSLR to manual mode, use the same exposure time (and aperture) and take multiple frames.  You need enough frames for a good statistical average but larger numbers are not usually necessary.  I usually shoot 16, sometimes I do 32 if I have a large number of light frames.

I've never used IP Camera Control so I can't comment on exactly how to use IPCC to do this.  IP and IPCC are no longer supported (which is why the developer released them as free programs).  The EOS-R is a newer camera and I'm pretty sure that it is not supported by IPCC.  Double check the supported cameras list, http://www.mlunsold.com/ilcameracontrol.html.  Additionally, IP probably won't directly support the CR3 format, again check the features and specs, http://www.mlunsold.com/ILImageProcess.html.

However, if you can convert the EOS-R CR3 format to one of the types that IP uses (FITS, TIFF or DNG all work), then ImagesPlus program will work just perfectly fine for calibration, stacking and image processing.

John Schnupp, N3CNL
2007 R1200RT +68,100
1995 XLH 1200 106,495 (retired)
Georgia, VT
44.7675°N, 73.1592°


Kevin Dixon
 

Thank you very much for the detailed information John.  I will be using an illuminated panel to create the flats.  The DSLR is attached to a Newtonian telescope.

I had read that I could set the camera to Av mode so that it chooses the proper exposure duration.  Have you found this to be an effective means to create effective flats?

Thanks again.

Clear skies,
Kevin


John Schnupp
 

Kevin,

I would only use the Av mode for the first frame, note the exposure time that the camera picked.  Then I would manually set the aperture and exposure times in Manual. 
Using a light panel it should be fairly consistent but by manually setting the exposure you would not need to worry about the camera changing anything during the series of flats.

John Schnupp, N3CNL
2007 R1200RT +68,100
1995 XLH 1200 106,495 (retired)
Georgia, VT
44.7675°N, 73.1592°


phils67
 

While using AV mode will work, I prefer to use AV mode for a single
flat to get an exposure time. Once I have this, I switch to manual to
take the series of flats, using the exposure time from the AV one. If
you check the histogram from the AV exposure, you can also decide to
slightly increase or decrease the exposure time to place the histogram
hump exactly where you want it.

Phil

On Mon, 2022-05-16 at 10:00 -0700, Kevin Dixon wrote:
Thank you very much for the detailed information John. I will be
using an illuminated panel to create the flats. The DSLR is attached
to a Newtonian telescope.

I had read that I could set the camera to Av mode so that it chooses
the proper exposure duration. Have you found this to be an effective
means to create effective flats?

Thanks again.

Clear skies,
Kevin


Kevin Dixon
 

Thanks very much John and Phil. I really like that approach to determining the exposure setting for flats with the EOS R.

Clear skies,
Kevin

----- Original Message -----
From: "phils67" <plsherman@...>
To: ImagesPlus@groups.io
Sent: Tuesday, May 17, 2022 11:37:20 AM
Subject: Re: [ImagesPlus] Taking flat frames with a Canon EOSS R

While using AV mode will work, I prefer to use AV mode for a single
flat to get an exposure time. Once I have this, I switch to manual to
take the series of flats, using the exposure time from the AV one. If
you check the histogram from the AV exposure, you can also decide to
slightly increase or decrease the exposure time to place the histogram
hump exactly where you want it.

Phil


On Mon, 2022-05-16 at 10:00 -0700, Kevin Dixon wrote:
Thank you very much for the detailed information John. I will be
using an illuminated panel to create the flats. The DSLR is attached
to a Newtonian telescope.

I had read that I could set the camera to Av mode so that it chooses
the proper exposure duration. Have you found this to be an effective
means to create effective flats?

Thanks again.

Clear skies,
Kevin


Chuck Sterling
 

Be sure to use the same manual parameters for your flat darks.


On Tue, May 17, 2022, 12:23 PM Kevin Dixon <ksbtk@...> wrote:
Thanks very much John and Phil.  I really like that approach to determining the exposure setting for flats with the EOS R.

Clear skies,
Kevin

----- Original Message -----
From: "phils67" <plsherman@...>
To: ImagesPlus@groups.io
Sent: Tuesday, May 17, 2022 11:37:20 AM
Subject: Re: [ImagesPlus] Taking flat frames with a Canon EOSS R

While using AV mode will work, I prefer to use AV mode for a single
flat to get an exposure time. Once I have this, I switch to manual to
take the series of flats, using the exposure time from the AV one. If
you check the histogram from the AV exposure, you can also decide to
slightly increase or decrease the exposure time to place the histogram
hump exactly where you want it.

Phil


On Mon, 2022-05-16 at 10:00 -0700, Kevin Dixon wrote:
> Thank you very much for the detailed information John.  I will be
> using an illuminated panel to create the flats.  The DSLR is attached
> to a Newtonian telescope.
>
> I had read that I could set the camera to Av mode so that it chooses
> the proper exposure duration.  Have you found this to be an effective
> means to create effective flats?
>
> Thanks again.
>
> Clear skies,
> Kevin










Geof Lewis
 

Hi Kevin,
I’ve never used the Av function on my DSLR to take flats, preferring to use manual and then check the intensity in IP by opening a frame and moving the cursor through the image. I typically look for between 20k and 28k ADU (16 bit scale) at the centre of the image.
In fact, I still use that method for my QSI camera with LRGB and Ha filters. I’ve used both day time sky flats and a light panel for the DSLR, but only a wall mounted light panel in my observatory for the QSI.
As Chuck comments, I then shoot flats and dark flats at the same exposure settings.
Cheers,

Geof

From: ImagesPlus@groups.io <ImagesPlus@groups.io> on behalf of Kevin Dixon <ksbtk@...>
Sent: Tuesday, May 17, 2022 7:23:41 PM
To: ImagesPlus@groups.io <ImagesPlus@groups.io>
Subject: Re: [ImagesPlus] Taking flat frames with a Canon EOSS R
 
Thanks very much John and Phil.  I really like that approach to determining the exposure setting for flats with the EOS R.

Clear skies,
Kevin

----- Original Message -----
From: "phils67" <plsherman@...>
To: ImagesPlus@groups.io
Sent: Tuesday, May 17, 2022 11:37:20 AM
Subject: Re: [ImagesPlus] Taking flat frames with a Canon EOSS R

While using AV mode will work, I prefer to use AV mode for a single
flat to get an exposure time. Once I have this, I switch to manual to
take the series of flats, using the exposure time from the AV one. If
you check the histogram from the AV exposure, you can also decide to
slightly increase or decrease the exposure time to place the histogram
hump exactly where you want it.

Phil


On Mon, 2022-05-16 at 10:00 -0700, Kevin Dixon wrote:
> Thank you very much for the detailed information John.  I will be
> using an illuminated panel to create the flats.  The DSLR is attached
> to a Newtonian telescope.
>
> I had read that I could set the camera to Av mode so that it chooses
> the proper exposure duration.  Have you found this to be an effective
> means to create effective flats?
>
> Thanks again.
>
> Clear skies,
> Kevin










Kevin Dixon
 

Thanks very much Geof and Chuck.

Clear skies,
Kevin


From: "Geof Lewis" <geoflewis@...>
To: "ImagesPlus" <ImagesPlus@groups.io>
Sent: Tuesday, May 17, 2022 2:43:58 PM
Subject: Re: [ImagesPlus] Taking flat frames with a Canon EOSS R

Hi Kevin,
I’ve never used the Av function on my DSLR to take flats, preferring to use manual and then check the intensity in IP by opening a frame and moving the cursor through the image. I typically look for between 20k and 28k ADU (16 bit scale) at the centre of the image.
In fact, I still use that method for my QSI camera with LRGB and Ha filters. I’ve used both day time sky flats and a light panel for the DSLR, but only a wall mounted light panel in my observatory for the QSI.
As Chuck comments, I then shoot flats and dark flats at the same exposure settings.
Cheers,

Geof

From: ImagesPlus@groups.io <ImagesPlus@groups.io> on behalf of Kevin Dixon <ksbtk@...>
Sent: Tuesday, May 17, 2022 7:23:41 PM
To: ImagesPlus@groups.io <ImagesPlus@groups.io>
Subject: Re: [ImagesPlus] Taking flat frames with a Canon EOSS R
 
Thanks very much John and Phil.  I really like that approach to determining the exposure setting for flats with the EOS R.

Clear skies,
Kevin

----- Original Message -----
From: "phils67" <plsherman@...>
To: ImagesPlus@groups.io
Sent: Tuesday, May 17, 2022 11:37:20 AM
Subject: Re: [ImagesPlus] Taking flat frames with a Canon EOSS R

While using AV mode will work, I prefer to use AV mode for a single
flat to get an exposure time. Once I have this, I switch to manual to
take the series of flats, using the exposure time from the AV one. If
you check the histogram from the AV exposure, you can also decide to
slightly increase or decrease the exposure time to place the histogram
hump exactly where you want it.

Phil


On Mon, 2022-05-16 at 10:00 -0700, Kevin Dixon wrote:
> Thank you very much for the detailed information John.  I will be
> using an illuminated panel to create the flats.  The DSLR is attached
> to a Newtonian telescope.
>
> I had read that I could set the camera to Av mode so that it chooses
> the proper exposure duration.  Have you found this to be an effective
> means to create effective flats?
>
> Thanks again.
>
> Clear skies,
> Kevin