Sony A7S Astrophotography Workflow Recommendations

[bgercken]

Hello,

 

Just started shooting astrophotography with an A7s Mk2 and I am trying to come up with a workflow that includes automated dark frame subtraction.

 

When using the Canon 6D I use PixelFixer which has a batch processing mode for this purpose and works great. Unfortunately PixelFixer does not support ARW.

 

Ideally, I would like to do this in camera raw with neutral settings but have not been able to find a way to script in CR. 

 

I can use batch processing in PS (with actions) to do this but would like to avoid the extra step (but in hind sight this is the same thing I am doing with PixelFixer).

 

Has anyone found I good work flow?

 

Thanks!

-bill

[adwb]

Can pixel fixer use .Dng raw files? if so use the free Adobe dng converter.

[bgercken]

adwb,

 

It totally does! I can't believe I missed that. That will work fine on the PC side. 

(Need to work on something for OS X - maybe photo mechanic.)

 

Thanks for opening my eyes... 

-bill

[bgercken]

adwb,

 

It totally does! I can't believe I missed that. That will work fine on the PC side. 

(Need to work on something for OS X - maybe photo mechanic.)

 

Thanks for opening my eyes... 

-bill

 

 

Bummer. Turns out that even though Pixel Fixer uses DNGs it can not recognize the Sony raw data.

 

So unfortunately, that did not work. Oh well back to PS method.

 

Thanks.

bill

[AndyWear]

I use Adobe Bridge for batch processing along with Adobe After Effects and Premiere, but those are expensive options.

[bgercken]

I use Adobe Bridge for batch processing along with Adobe After Effects and Premiere, but those are expensive options.

 

 

Andy,

 

I have the full CC but have not tried after effects.

 

Is there an easy way to script something like this? The steps I need are, select a dark frame image, subtract it from an image, and then save the new image, repeat using the same dark frame for each new image.

 

Thanks for the reply.

-bill

[Guest all8]

There are some astro image processing applications which might be more scriptable. Deep Sky Stacker is a fairly popular one, but there are a few others.

 

Also, for your long exposures you can use the Automatic NR of the camera, it takes a dark frame after a shot, and then subtracts that from the shot. That at least works for unto 30 sec exposures, longer than that I'm not sure.

 

And its also worth checking if a dark frame is even necessary, if you can use lower ISO you might find that there is not to much noise. My experience was that the Automatic NR, i.e. Dark Frame, was not achieving very much ... if anything ... because apparently the Sony sensors are pretty good for that kind of noise. YMMV.

[bgercken]

There are some astro image processing applications which might be more scriptable. Deep Sky Stacker is a fairly popular one, but there are a few others.

 

Also, for your long exposures you can use the Automatic NR of the camera, it takes a dark frame after a shot, and then subtracts that from the shot. That at least works for unto 30 sec exposures, longer than that I'm not sure.

 

And its also worth checking if a dark frame is even necessary, if you can use lower ISO you might find that there is not to much noise. My experience was that the Automatic NR, i.e. Dark Frame, was not achieving very much ... if anything ... because apparently the Sony sensors are pretty good for that kind of noise. YMMV.

 

 

Thanks I will check into Deep Sky Stacker I have not looked at that yet.

 

In camera noise reduction is not really an option for me as I am shooting panorama's and the MW moves pretty fast. My capture workflow is to shoot one or two rows every 15-30 degrees (15-30s each) and then capture the same same for the foreground (2-4 minutes each @iso 4000) and then capture the dark frames.

 

Even at relatively lower ISOs (5K-6400) there is a lot of sensor noise without the NR turned on. Dark frame subtraction definitely improves that. Also, I am dong very long exposures for foreground shots (2-4 minutes) which definitely causes noise. 

 

Thanks for the feedback.

 

-bill

[bgercken]

I was able to resolve this by using an action in photoshop to do the work and batch process it using Bridges->Tools->Photoshop->Batch option.

 

To use the action I rename the dark frame that I want to use to "DF.ARW" and reference in the action. The action has an "open" and a "save"  step. When it loads an image it opens in camera raw, which allows me to apply the lens profile (and appears to record anything you do in CR). 

 

The batch processing in bridge allows you to select sources and specify a destination (or rename the target). Works very well. 

 

Cheers.

-bill