PDA

View Full Version here: : Light polution filter(s)


allan gould
07-12-2006, 10:03 AM
I'm looking at getting a light polution filter to do some DSLR photography from BrisVegas. No kidding if I go longer than 5 secs I have sky glow. At 10 seconds at iso800 then my shots are orange. From the experience of others what would be the best LPR filter to do longer DSLR shots and what time could I expect to go to. Or is this all a pipe dream?
Thanks for your advice
Allan

rmcpb
07-12-2006, 10:44 AM
Have a look at this thread (http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/1286619/page/0/view/collapsed/sb/5/o/all/fpart/1#Post1287293) on CN, in particular the comments on the Orion Skyglow filter. It appears that this is one of the uses for this filter so it may be worth a try for you.

avandonk
07-12-2006, 11:30 AM
In my opinion the 'best' light pollution reduction filter is the Hutech LPS-P2.
Below is a picture of spectra I made some time ago.
From the top
Kenko 'H Alpha'
Hutech Nebula filter
LPS filter (brand unknown) but this is typical for most LPR filters.
Hutech LPR filter
Mercury street lamp
High pressure Sodium street lamp
Tungsten globe

As you can see the Hutech LPR has two extra peaks between the light pollution spectral lines. This gives it better colour balance as well as higher useful total transmission of light from stars and nebulae.

All of the pictures I have produced have been from my home in Eltham which is about 20k from Melbourne.

I can expose for ten minutes at an ISO of 400 at 640mm F6.4. At 300mm at F2.8 and ISO 200 I have even exposed for twenty minutes.
With the nebula filter even longer than the LPR filter. The other very good thing about the Hutech filters they are optically very good and If you exchange the Nebula filter for the LPR filter, focus does NOT change. They are optically identical.

Bert

allan gould
07-12-2006, 01:14 PM
The reviews as well as the picture from Bert were most informative. Many thanks for all that. Where in Australia would you purchase Hutech LPS-V3
Allan

Striker
07-12-2006, 01:21 PM
I too agree with Bert regarding the Hutech LPS filter.

But also consider the UHC-S as it will cut out more skyglow then the LPS but the color correction is not as good as Bert said....but still a great option.

No auzzie retailers dealing with hutech as far as I know Allan.