Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

H-Alpha filter with DSLR cameras

  • Please log in to reply
28 replies to this topic

#26 Reece

Reece

    Vostok 1

  • -----
  • topic starter
  • Posts: 179
  • Joined: 18 Jan 2021

Posted 08 April 2021 - 02:23 PM

I have never purchased a filter before. Would these be 2 inch filters I should be looking at to avoid vignetting on an APS-C sensor Canon 20Da? 



#27 klaussius

klaussius

    Apollo

  • *****
  • Posts: 1,094
  • Joined: 02 Apr 2019
  • Loc: Buenos Aires

Posted 08 April 2021 - 02:31 PM

Since you're using lenses, you'll need a clip-in filter.

 

Beware that some lenses have such a short flange distance that they can't be used with clip-in filters, they bump on the filter. Most notably EF-S lenses IIRC have that problem.


  • Reece likes this

#28 T~Stew

T~Stew

    Messenger

  • -----
  • Posts: 406
  • Joined: 29 Sep 2020
  • Loc: central Ohio

Posted 08 April 2021 - 04:57 PM

Which filter were you using that caused this problem? I don't have any experience with clip filters yet, but the round filter is a bit of a hassle with mounting to the front of a lens. The filter drawer would fix this for sure. Was it with full frame or APS-C sensor?

 

The OIII will be affected by moonlight for sure. But it'll be useable data versus unfiltered during the full moon. Your H-a data will be great. The emission nebulae I've shot during full moon with the l-enhance filter have been decent.

It was my full frame 6D. I've generally heard good reviews with clips and the APS-C so the issue might be primarily ff and the tighter space it fits into. It still works but requires a bit extra cropping, which kind of defeats some of the purpose of using the ff vs crop sensor. Hopefully I can go to 2" filters in the lens to be able to swap cameras more easily. I just picked up an old canon lens that was suppose to originally come with a holder for 48mm filters, but it must've been swapped for a gel holder. And now I can't find any replacement drawers for 48mm filters. Darn! I may just unmount the filter and see if the gel holder will hold it.



#29 Reece

Reece

    Vostok 1

  • -----
  • topic starter
  • Posts: 179
  • Joined: 18 Jan 2021

Posted 09 April 2021 - 09:35 PM

I have done some reading on filters.

 

It appears that the L-Extreme works better with slower lenses as there is some loss of light transmission when using it with fast lenses such as my Canon 200mm F/2.8. The L-Extreme would allow wavelengths of light which might reduce it's usefulness under a bright moon. It is also more expensive. 

 

The L-Enhance filter appears to work fine at F/2.8. One buyer of this filter who seemed quite knowledgeable claimed it suffers considerable loss of light transmission at F/2 however.

 

Astronomik makes a 12nm h-alpha filter. This lens has a wider passband at the h-alpha wavelength than the L-Enhance or L-Extreme. It would presumably be less susceptible to the reduced light transmission effect of the fastest lenses. It would be strictly h-alpha. I am not sure of the significance of this in practice for the imaging of nebulae and planetary nebulae.

 

Baader appears to make filters specifically for fast telescopes such as the RASA. I have been unable to find a DSLR clip filter from them for fast camera lenses unfortunately.

 

I may wish to purchase a Sigma 85mm 1.4 at a later date. It would be frustrating to purchase equipment now which would be sub-optimal with future equipment purchases. 


Edited by Reece, 09 April 2021 - 10:10 PM.



CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics