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Full Spectrum A7S - Filter advice

astrophotography
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#1 tsk1979

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Posted 16 April 2019 - 12:00 AM

I am looking at various filters for Astrophotography for full spectrum Sony A7S camera. I am interested in wideband, but not narrowband

 

I see the Astronomik filters (Light pollution) or similar STC Astro filters

https://www.cyclopso...sony-alpha-7-9/

 

What advantage do these give over normal lens screw on filters? Any specific disadvantages for these?

 

If anybody is using high iso A7S untracked on 35-70mm focal lengths please advise on your workflow and results?

Also if you recommend other filters do share.

 



#2 Jim Waters

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Posted 16 April 2019 - 12:24 AM

Do some research on this.  Clip-In Filters for Full Frame camera's produce vignetting.  The amount depends on the filter and camera.  Lens screw-on LP filters can result in filter spectrum-shift for F.L.s under ~100mm.


Edited by Jim Waters, 16 April 2019 - 02:38 PM.


#3 t_image

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Posted 16 April 2019 - 07:14 AM

I am looking at various filters for Astrophotography for full spectrum Sony A7S camera. I am interested in wideband, but not narrowband

 

I see the Astronomik filters (Light pollution) or similar STC Astro filters

https://www.cyclopso...sony-alpha-7-9/

 

What advantage do these give over normal lens screw on filters? Any specific disadvantages for these?

 

If anybody is using high iso A7S untracked on 35-70mm focal lengths please advise on your workflow and results?

Also if you recommend other filters do share.

There is some decent discussion here on different filter results:

https://www.cloudyni...euibii-filters/

 

Clip-in filters designed for the correct sensor are better than filter before objective all day.....

 

Note LP filter have a bad color cast so you will need to learn how to color correct....(https://www.cloudyni...-at-processing/)

 

Note the a7s is a tool best suited for longer focal length as the 8.4micron pixels reduce your spatial resolution greatly with wide shots.....

Also investment in a cheap fast prime (even a used Canon or Nikon lens mechanically adapter) exploits the benefits of a7s high ISO much.

 

Also, most fun can be had with tracking and a h-alpha NB filter....

But widefield with high ISOs and a7s is a good place to start to get your feet wet...

 

Enjoy!



#4 tsk1979

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Posted 16 April 2019 - 01:37 PM

Thank you

I was looking at A7/A7S specific filters. I plan to use 

 

1. 20mm F1.4 for milky way photography

2. 85mm F1.8 for Nebulae and galaxies

 

These will be my starter lenses.

 

From filter web page it says no vignetting below 14mm. So I guess I should be good




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