light pollution filter tests svbony

[realflow100]

ive been doing some tests with this filter and i'm not sure im using it correctly
SVBONY Telescope Filter 1.25 inches UHC
I took two pictures to compare without and with the filter.
50mm F1.8 lens

No tracking because i was lazy.

First picture is without the filter
iso 400 5 seconds short exposure.

Second picture is with the filter
iso 400 and 25 seconds long exposure

I'm not sure what its supposed to do to the image. beside having a large increase in exposure time
Maybe theres a little more contrast and stars a bit more visible but its hard to tell.

[realflow100]

Anyone?
Should I instead try to go for a specific filter wavelength like a narrowband filter for orion nebula or something else?
should a UHC filter really cut down so much light I need to more than double the exposure time? from 5 seconds to 25 seconds?

[Graeme1858]

Hello RF

Are those overhead cables in your images?

I have an IDAS D1 for my Canon, I never used it much because I didn't like the changes in colour it produced. But I don't remember having to increase the exposure to such a degree.

Your Svbony appears to have improved the image, the contrast is better. Seems you are using it correctly. What's it like visually when there are no clouds?

Regards

Graeme

[ARock]

I am able to increase ISO with the SVBONY UHC. This is with a Canon T3i and Aperture=80mm, FL=400mm scope.

For longer exposures (say 2min) in LP skies, I previously had to reduce ISO to 200 with my DSLR, otherwise everything turns white. With the SVBONY UHC, I can increase ISO to 800, and still get decent contrast for the sky.

Compare 20sec exposures for 200-400mm lenses with ISO=400 without UHC, and ISO=1600 or 3200 with UHC. On a cloudless sky.

[Greenman]

I am able to increase ISO with the SVBONY UHC. This is with a Canon T3i and Aperture=80mm, FL=400mm scope.

For longer exposures (say 2min) in LP skies, I previously had to reduce ISO to 200 with my DSLR, otherwise everything turns white. With the SVBONY UHC, I can increase ISO to 800, and still get decent contrast for the sky.

Compare 20sec exposures for 200-400mm lenses with ISO=400 without UHC, and ISO=1600 or 3200 with UHC. On a cloudless sky.

Sounds reasonable for a low cost filter.

[realflow100]

yes those are powerlines. sorry.
Also I havent been able to test with no clouds because its SO CLOUDY HERE especially at night a lot of the time
I dont know when we will have a perfectly clear night here in orangeburg SC

I used 50mm F1.8 because I can get away with shorter exposure time (30 seconds or under)

I have 55-250mm F4 to F5.6 IS II lens if I want to zoom in more. but at that small aperture I can go way past 30 seconds exposure time if I simply decrease the iso so its reasonably exposed.
Also the filter wont fit on that lens. I have no way to adapt it to fit that lens.
for now it only works with my 50mm F1.8 lens. unless I buy a new filter of 58mm diameter.
if I do buy a new filter what would be a better filter to get? (better reduction of light pollution without reducing nebulas and galaxies as much?) Something that will work best on the bright nebula and galaxy targets. not the fainter stuff like horsehead.

I have to use a low iso at F1.8 otherwise the whole sky is blown out white from the severe light pollution

Should I instead keep the same exposure time and raise the iso when using the UHC filter? this way has more noise. with same brightness as no filter. but shorter exposure time.
Or keep the same iso and raise the exposure time? when using the UHC filter?. doing it this way has about the same amount of noise as no filter. with the same brightness as no filter but when using the UHC filter

I'm not sure what my white balance on the camera should be.

I'm also not sure what targets would be best suited for the UHC filter based on what wavelengths of light it affects.

[ARock]

I have to use a low iso at F1.8 otherwise the whole sky is blown out white from the severe light pollution
Should I instead keep the same exposure time and raise the iso when using the UHC filter? this way has more noise. with same brightness as no filter. but shorter exposure time.

I just use the UHC to be able to use the higher ISO and not get a blown out sky. But my setup is different from yours. Try it and see what you get. Use the maximum exposure time you can get, and then adjust ISO with and without the UHC.

I use the UHC on everything, mainly to get better contrast on the sky.

[realflow100]

Does it make stars fainter? or the same brightness?
are stars the same brightness but the sky darker?
Or does UHC filter on work on extended objects like nebula galaxies ect?

my maximum exposure time is about 30 seconds at any focal length. since im using an ALT-AZ super cheap goto star tracker.
otherwise there would be star trailing at the edges of the image in a spinning motion.

[ARock]

The effect on stars is minimal once I stack enough subs and process. I would think everything gets darker with the filter, the sky just more than others.

This image was livestacked using AstroToaster with 50 RAW subs 20 secs each, ISO=3200 with darks,bias, flats. Canon T3i with the SVBONY UHC and a Meade Adventure 80mm on a motorized EQ mount.

AstroToaster has settings to stretch and increase saturation of colors.

[realflow100]

Tested on a clear night.
Didnt seem to really do anything except lengthen the exposure time change the background sky color tint. and make a strange colored pink-red vignette around the edges. Filter is too small for lens.. a larger one would fix that problem. I have a weird adapter attached to the lens hood to get it to fit lol.

The ICE broadband LIPO filter i have takes less exposure time but doesnt have as strong as effect. seems to more mild but an improvement over no filter still. no vignetting.

[John Baars]

An UHC doesn't work on stars, and for that matter not on galaxies either.
It works on some (many) planetaries and emission nebulae.
Furthermore it darkens the lightpolluted sky. Having seen you images, it works!
Still, the well known gasoline filter works best.

[realflow100]

Not possible to go anywhere. im especially not going anywhere considering the virus situation either.

its way too cold right now too. I have to be indoors and shoot out my open window. and its STILL kinda chilly

[Frank]

Have you tried a Variable Filter? From nunerius articles I have read and from what few sites that allow photographs to be posted with reviews (Amazon was one of them) seems like the Svbony and Celestron Variables are pretty good for the price and you can control the degree of darkness you want to use. I am looking into filters recently as well as EPs to add to my telescope and far from rich so these 2 mentioned here have hundreds of great reviews over even more expensive Variable filters. Seems like Svbony is upoing theor game a lot lately with quality and those Youtube videos saying they use plastic lenses, not in the ones I have used they don't. Svbony with the image quality and price, may pick one up?

[realflow100]

I have a variable filter already.
all it does is change brightness from 1% to 40% when you adjust it. its not for adjusting light pollution stuff at all.
yes its glass not plastic.