I had a beautiful night for this comparison test of my new IR Filter test.
The sky cleared up to give 8/10 seeing and 10/10 Transparency.
The below images of Carina Neb and Keyhole are taken under almost identical conditions, seeing temp etc.
All images taken with ED80, modified Toucam 840k Pro II, Focal Reducer, stacked in Registax, all processed equally in PhotoShop CS.
Make up your own mind about the results, but as usual feel free to comment or help.
IMAGE 1:
In the 1st panel is Carina with no filters at all. Just raw Toucam.
In the 2nd Panel I used the crummy little Toucam Lens IR Filter.
In the 3rd panel I used a proper Astronomical Imaging IR Cut Filter.
IMAGE 2: The full size images cropped to show real-size detail.
the IR cut filtter has made the stars look heaps better, they look more sharper and smaller/less bloat (if you know what I mean) to me. But I dont like the lost color can you get it back to red somehow?? then it would rock. I cant believe you are getting these with a simple webcam you are the man, well done mate
Ken,
Do you know the characteristics of these IR filters? Undoubtedly, the have different transmission and IR wavelength characteristics. I prefer the Astronomical IR filter as it really does cut down star bloating (as Joe mentioned), however this can be remedied in processing techniques - its still best to prevent it occuring in the first place.
IR filters could start at anywhere between 659nm through to 800nm, hence its difficult to make direct comparions. In addition to this they all are likely to have different transmission characteristics ranging from 60% to 95%. If your Astronomical IR filter doesnt have a good transmission rate, then you're going to need to increase exposure time to compensate - this *could* partly be the problem why the colours are off with the Astronomical filter. Finally, you need to also consider spectral response of the Toucam. Its will not be 100% over all visual wavelengths thats for sure.
If your Astronomical IR filter doesnt have a good transmission rate, then you're going to need to increase exposure time to compensate - this *could* partly be the problem why the colours are off with the Astronomical filter.
Jase,
if I take longer exposures than these, the Amp Glow dominates the image. I did take an image only 30 seconds longer and 3/4 of the image was washed out and lost to Amp Glow.
So, unfortunately I don't have the luxury of longer exposures than 180 seconds, without getting the 'Amp Off' mod done.
Joe, less noise in the IR cut filter image was done by me using PhotoShop actions. I forgot to do the other 2.
To me, the Toucam filter and the IR Cut filter give identical clean stars.
None of the images have been processed to 'nice' level. I usually do quite a bit of processing with them but that would not give a comparison of data collected in this instance. So I left them almost Raw.
We prefer the crummy little Toucam filter the best
Both the filters do a great job on star bloat but there's a loss of detail and colour with the IR cut filter. Maybe it would perform differently with a DSLR
I say the original Toucam filter for me..
I reckon it gives the best result as the onboard camera processing is designed around having this filter present...
great comparison Ken..
cheers
We prefer the crummy little Toucam filter the best
Both the filters do a great job on star bloat but there's a loss of detail and colour with the IR cut filter. Maybe it would perform differently with a DSLR
I agree. I think the Toucam innards may be different compared to DSLR's.
As Gary says:
Quote:
Originally Posted by Garyh
original Toucam filter .. I reckon it gives the best result as the onboard camera processing is designed around having this filter present"
