I have read many forums and articles regarding a light pollution filters for an unmodded DSLR. What are your recommendations/experiences? Looking at either the UHC or CLS.
I have a Canon DSLR which I won’t be modding as I use it for normal photography as well. I am in a bortle 5 zone.
I think the usefulness of a filter will depend on what type of light pollution you're trying to remove.
The old sodium or mercury vapour lamps put out light at specific frequencies that could be removed by filters. The new LED lights use many different frequencies that can't be filtered out.
Other members more knowledgeable about the UHC or CLS filters can no doubt add their wisdom...
You really aren't going to notice any difference between a UHC & CLS filter, they are basically the same thing. The good thing with having an unmodded DSLR is you don't have to worry about getting the "CCD" version of a CLS filter which are more expensive as they have an IR cut-off at ~710nm. The standard ones don't but it isn't needed with an unmodded camera.
You don't say if you have a full frame or crop sensor camera, or if you want a clip filter or not. Optolong does pretty decent UHC & CLS filters at a reasonable price, both clip in & other standard sizes, that you may find useful. Being in bortle 5, you will appreciate the greater contrast either of these will provide.
You really aren't going to notice any difference between a UHC & CLS filter, they are basically the same thing. The good thing with having an unmodded DSLR is you don't have to worry about getting the "CCD" version of a CLS filter which are more expensive as they have an IR cut-off at ~710nm. The standard ones don't but it isn't needed with an unmodded camera.
You don't say if you have a full frame or crop sensor camera, or if you want a clip filter or not. Optolong does pretty decent UHC & CLS filters at a reasonable price, both clip in & other standard sizes, that you may find useful. Being in bortle 5, you will appreciate the greater contrast either of these will provide.
Cheers,
Mark
I have a crop sensor and clip in would be handy as I don’t see how you can attach a 2” filter on a 135mm lens. I’ve read that you can use step down threads but that can cause vignetting so clip in would be the way to go.
If your crop sensor camera is a Canon, you won't be able to use Canon EF-S lenses with a clip-in filter. You can use Canon EF lenses or third party lenses intended for crop sensors (or full frame), just not Canon EF-S. That may or may not matter for your lens collection.
I have a crop sensor and clip in would be handy as I don’t see how you can attach a 2” filter on a 135mm lens. I’ve read that you can use step down threads but that can cause vignetting so clip in would be the way to go.
Which make and model of 135mm lens do you have? What is its front filter thread diameter? It is possible that something MIGHT be possible without too much compromise depending on your lens aperture.
Depending on the lens performance you may even like the lens stopped down a little. In that case the restricted circular aperture offered by front mounted filters would be better than stopping down the lens via its normal aperture blades as there would be no attendant diffraction spikes induced by the aperture blades of your lens if stopped down.
Which make and model of 135mm lens do you have? What is its front filter thread diameter? It is possible that something MIGHT be possible without too much compromise depending on your lens aperture.
Depending on the lens performance you may even like the lens stopped down a little. In that case the restricted circular aperture offered by front mounted filters would be better than stopping down the lens via its normal aperture blades as there would be no attendant diffraction spikes induced by the aperture blades of your lens if stopped down.
It has a 77mm thread on the front. I have seen light pollution filters with a 77mm thread but unsure yet if these are any good/better than using a Astronomik or Optolong clip in filter.
The Samyang 135mm f/2 is a very sharp lens, even wide open at f/2, but does get some 5-10% sharper at f/4 so the size of any front mounted filter could be reduced somewhat, if you for instance did not want to shoot wide open at f/2. Do you have any preference for how you'd like to use the lens: Wide open or stopped down? If it's wide open you probably only have one type of front mounted filter available to you, possibly only in a couple of sizes 77mm or 72mm with a step down ring that shouldn't vignette. If stopped down there are some other types available or possibly just lower cost options you could try.
With anything related to light pollution it may not be that easy to say this type of filter is better than that, especially when you're talking about an UNMODIFIED DSLR, since it too will have its own built UV-IR filter built in over the sensor and in Canon's case that will typically allow for no more than ~25% transmission of Hydrogen Alpha. The trick is of course to get rid of everything else that isn't the true sky. That is possible to an extent if your light pollution is from Sodium Type Street lighting. If it's LED based or more broad band light pollution, it can be reduced somewhat, but nothing like what's possible for results with simple filters designed to deal with Sodium Based street lightning.
So that begs the question: What type of light pollution do you have that you want to deal with?
The main light pollution I have in my area is the glow from the city which give my images a yellowish tinge. I live in a Bortle 6 zone.
Just an idea. Would I be better off astro modding my 1200D and keep that as my dedicated portable astro camera that way I can still use my 700D for everyday photography? The only issue with that is I am not confident enough to mod the camera myself and the services I found nationwide are no less than $500 which doesn't seem like it's worth it as I am not out every night taking photos.
I was considering a cooled OSC but the purpose of this setup is to be very portable (DSLR and batteries) and I have no intention of adding an autoguider yet.
Quote:
Originally Posted by JA
The Samyang 135mm f/2 is a very sharp lens, even wide open at f/2, but does get some 5-10% sharper at f/4 so the size of any front mounted filter could be reduced somewhat, if you for instance did not want to shoot wide open at f/2. Do you have any preference for how you'd like to use the lens: Wide open or stopped down? If it's wide open you probably only have one type of front mounted filter available to you, possibly only in a couple of sizes 77mm or 72mm with a step down ring that shouldn't vignette. If stopped down there are some other types available or possibly just lower cost options you could try.
With anything related to light pollution it may not be that easy to say this type of filter is better than that, especially when you're talking about an UNMODIFIED DSLR, since it too will have its own built UV-IR filter built in over the sensor and in Canon's case that will typically allow for no more than ~25% transmission of Hydrogen Alpha. The trick is of course to get rid of everything else that isn't the true sky. That is possible to an extent if your light pollution is from Sodium Type Street lighting. If it's LED based or more broad band light pollution, it can be reduced somewhat, but nothing like what's possible for results with simple filters designed to deal with Sodium Based street lightning.
So that begs the question: What type of light pollution do you have that you want to deal with?
The main light pollution I have in my area is the glow from the city which give my images a yellowish tinge. I live in a Bortle 6 zone.
I would say it's a little unusual to notice a yellowish tinge unless you are shooting a nightscape at much a wider angle than available with a 135mm lens on a crop sensor camera. Just checking - Are you sure your white balance is set correctly to Daylight? Still it might be just that way. Certainly if you look at the street lights and they are yellow/orange then it's likely its a high pressure sodium lamp, whose light can be tamed somewhat with a Neodymium type filter, sometimes called didymium or redhancer, red-intensifier filters. The best that I've tried / seen is the Marumi ? Crystal Optics brand. Hoya also make a type, but I've tried those and they don't cut as much as the Marumi nor is the contrast as good. There are other Astro brands too with similar filters, sometimes called skyglow filters as well as other types, which sometimes create a significant colour cast, so try first if possible. There are more expensive name brands also available such as Baader and IDAS, etc...
Quote:
Originally Posted by Saturn488
Just an idea. Would I be better off astro modding my 1200D and keep that as my dedicated portable astro camera that way I can still use my 700D for everyday photography? The only issue with that is I am not confident enough to mod the camera myself and the services I found nationwide are no less than $500 which doesn't seem like it's worth it as I am not out every night taking photos.
I was considering a cooled OSC but the purpose of this setup is to be very portable (DSLR and batteries) and I have no intention of adding an autoguider yet.
For now use your DSLR as is, nice and portable as you say, and try to get somewhere dark to see what's possible before buying new gear. A modified DSLR will get you over twice as much exposure as an unmodified DSLR (~65% transmission Versus ~25% transmission of Hydrogen Alpha) , but really ONLY in the Hydrogen ALpha wavelengths / deep reds. There's still plenty to capture using an unmodified DSLR and its more muted (only in the deep reds) RGB sensor if you go for broadband targets. If you're thinking of a new camera at some stage, some of the FujiFilm mirroless cameras have excellent Hydrogen Alpha Response (~45% transmission) in their standard (unmodified state). I'm not sure if that's across all models or just the earlier models like the Pro1 and X-E1.
The image on the left is without flats, on the right with flats.
Think the flats I captured wernt any good as its making the corners bright.
A lot of yellow was removed using background extractor in pixinsight but I feel I can get better results with a filter as the image does look a little flushed out.
Thoughts?
Quote:
Originally Posted by JA
I would say it's a little unusual to notice a yellowish tinge unless you are shooting a nightscape at much a wider angle than available with a 135mm lens on a crop sensor camera. Just checking - Are you sure your white balance is set correctly to Daylight? Still it might be just that way. Certainly if you look at the street lights and they are yellow/orange then it's likely its a high pressure sodium lamp, whose light can be tamed somewhat with a Neodymium type filter, sometimes called didymium or redhancer, red-intensifier filters. The best that I've tried / seen is the Marumi ? Crystal Optics brand. Hoya also make a type, but I've tried those and they don't cut as much as the Marumi nor is the contrast as good. There are other Astro brands too with similar filters, sometimes called skyglow filters as well as other types, which sometimes create a significant colour cast, so try first if possible. There are more expensive name brands also available such as Baader and IDAS, etc...
For now use your DSLR as is, nice and portable as you say, and try to get somewhere dark to see what's possible before buying new gear. A modified DSLR will get you over twice as much exposure as an unmodified DSLR (~65% transmission Versus ~25% transmission of Hydrogen Alpha) , but really ONLY in the Hydrogen ALpha wavelengths / deep reds. There's still plenty to capture using an unmodified DSLR and its more muted (only in the deep reds) RGB sensor if you go for broadband targets. If you're thinking of a new camera at some stage, some of the FujiFilm mirroless cameras have excellent Hydrogen Alpha Response (~45% transmission) in their standard (unmodified state). I'm not sure if that's across all models or just the earlier models like the Pro1 and X-E1.
The image on the left is without flats, on the right with flats.
Think the flats I captured wernt any good as its making the corners bright.
I prefer the one on the left without the flats. The one on the right is NQR with greens etc...
Quote:
Originally Posted by Saturn488
A lot of yellow was removed using background extractor in pixinsight but I feel I can get better results with a filter as the image does look a little flushed out.
Thoughts?
In those areas there should be a yellowish/orange/brownish glow in certain areas as that is the core of the Milky Way around M8 & M20. This can be seen in the much wider widefield (low res) image below ...
I prefer the one on the left without the flats. The one on the right is NQR with greens etc...
In those areas there should be a yellowish/orange/brownish glow in certain areas as that is the core of the Milky Way around M8 & M20. This can be seen in the much wider widefield (low res) image below ...
Best
JA
Stunning image JA!
What lens was used?
I noticed the ISO 800 and the f1.4 in the image title (and number of frames and exposure time).
The following image is a composite of several images with the camera panned between shots (groups of shots) so it's not just one small section. Done in an area where I used to have nice dark skies until the installation of all of the new LED street lights, one of which shines into my back yard and lights up 2/3 of the yard, good for thieves and burglars I guess (I hope the mongrels trip over my junk, lol).
I had a lot of trouble trying to process the image until I did some basic reading on gradients and obtained a free program I still don't really know how to use but the overall results aren't too bad for my playing around.
14mm f2.8 Rokinon (Samyang) lens, Nikon D810 just 15 frames per image section at 25 seconds (maybe ISO 2200, I don't remember but can look that up).
In saying that did you select a lower ISO to keep noise lower?
I don't know how noisy my images may be, my eyes aren't as good as I wish they were. I just like to pretend it's all stars.
I'm a little ashamed, I have access to a few properties reasonably close where the dark skies are amazing, starting at around 15 minute drive to 40 minute drive which I haven't taken advantage of yet because of health but I really should soon while we still have our reasonably crisp winter skies (and no fear of treading on a tiger snake in the dark).
In keeping with the theme of this thread you would know this JA because you have the Nikon D810 from memory, do they accept any clip in type filters?
I've been curious with an occasional lens without filter thread (like the 14mm) but it would also solve the problem of needing a range of different sized filters for a range of lenses if it does take clip in units.
And sorry, I know I can look this stuff up online but I'd rather hear from someone I know has experience than someone who just thinks they know the answers.
Stunning image JA!
What lens was used?
I noticed the ISO 800 and the f1.4 in the image title (and number of frames and exposure time).
Thx Leo.
I've tried to answer a few times, but get timed out. Quick answer now is that the lens used was a Sigma Art 35mm f/1.4 shot wide open and UNTRACKED on a fixed tripod for max duration of 15s. The camera used was a Nikon D600 at ISO800. Very clean output but decided to shoot at ISO 800, not much higher as there's no need to and you get more dynamic range with lower ISO. With sufficient dynamic range you can extract more in post if you want to. I would happily shoot it at ISO 400 and have shot it as low as ISO100.
The time out is a bit of a pain, whether clearing your cache would help, heaven knows I just though about it but haven't tried it myself and since the problem is affecting everyone it seems it's more server side, host/server issues amdin should be able to get answers to on either independent forums with mention of vbulletin and version.
I used to be an admin at a large site some years back with 3,000,000 members world wide but members themselves and the site owner could come up with the issues and fixes. Sometimes it's a version update that can throw bugs out left right and centre. Thankfully I never had to deal with issues like this.
OK, it's an old version of VBulletin, I'll look and see if I can find any answers later and pass the info along. VB3.8.7 released August 2010.
The image is spectacular for the D600 though my dream was always to get the D610 till the 810 came up at a price I couldn't pass up with only 70,000 or thereabouts on shutter count. In near new condition cosmetically, someone who looked after his cameras as well as I look after mine (I still have a near new F601 and F801 here on my shelf).
I'm lucky on a pension to afford any of this stuff, the sky really is the limit I'm soon learning.
I have a 35mm Rokinon, purchased used but I can't achieve infinity focus at F1.4 (no comparison to the Sigma-art I know that). One day I''l find a fix on youtube or some other dumb site and strip the lens down and repair it myself, if I ever find said information. I found it for the 14mm, the 135mm but not the 35mm. Stopping down is always an option but that somewhat defeats the purpose f throwing money at an f1.4 lens for astro use.
Quick question, I recently saw a formula which throws the 500 rule out with the bath water and lists a 14mm maximum exposure time at 16.x seconds, would you happen to know this formula?
I lost the link I found it through.
Thanks!
Still, for an old fella in my 60s with bad eyesight I think my images are good enough to fool those who have no idea what they are looking at, including myself.
I would however love to play with a 35mm lens for the regions of the Milky Way.
In keeping with the theme of this thread you would know this JA because you have the Nikon D810 from memory, do they accept any clip in type filters?
I've been curious with an occasional lens without filter thread (like the 14mm) but it would also solve the problem of needing a range of different sized filters for a range of lenses if it does take clip in units.
And sorry, I know I can look this stuff up online but I'd rather hear from someone I know has experience than someone who just thinks they know the answers.
Great image Leo. Incredible view!
There are a few brands of clip in filters for full-frame Nikon cameras. There are many types and brands. Here are a few...
I have the STC one, which fits my D800, but as yet it's untested. With any of the filters take care or pretest (if you can) because the 14mm f/2.8 may present some challenges in terms of an even illumination/filtering across the frame.
Quick question, I recently saw a formula which throws the 500 rule out with the bath water and lists a 14mm maximum exposure time at 16.x seconds, would you happen to know this formula?
I lost the link I found it through.
Thanks!
With any of these exposure "rules", more like guides, aside from focal length, FOV multiplier, it's all a question of a few extra things:
the amount of star trailing you can tolerate
the distance to the Celestial pole (centre of apparent star rotation)
whether you like to zoom in for a tight view or happy to view image as a whole
I've used the 500 rule a few times, but personally much prefer something like 300 to 400 for untracked images on various wide and normal FF focal lengths that I've applied it to.
On your 14mm Samyang, depending on where you are pointing in the sky , you may prefer to use a lower numbered "rule". If you are shooting with your frame centre near the South Celestial Pole then your star trails will be shorter than if you are shooting with your frame centre well away from the SCP. This means significantly longer star trails for the same exposure duration in the latter case. It therefore might be better to go for something in the 200 to 300 range range, so your suggestion of 16 seconds (16 x 14 = 224), seems like a reasonable choice.
There is an exposure "rule" which also takes account of the distance (angle) to the SCP, involving the cosine of an angle, but your suggestion of 16 seconds will get you out of trouble, perhaps a little higher to 20 seconds if you need some more depth. If you are in a darker location, shoot to lower ISO as there's no need to increase the sensitivity too much, as all this will do is reduce dynamic range and if excessive, crush colours.
Thanks JA, much appreciated!
I hadn't thought about star trails as I get further from the celestial pole which shocks me, it's common sense. I haven't had a chance to get out for a while and now our weather seems like it's turned nasty, anyone would think it was still winter.
When the sky clears next I will get out. I've noticed 25 second exposures still get me elongated stars, more outer edges. I'll next run at 16 seconds though I last night hand filed a piece of aluminium stock I had laying around and found it clamps nicely into my EQ5 PRO head, easier than setting up a scope, just one modified piece of aluminium stock and a tracking mount outside, may allow me to use higher zoom lenses.
I'd like to try my old 70-200 f2.8 I purchased new in 91. It's the 16 glass elements and should produce crisp images. The autofocus has always been a little crappy for the price of the lens new but the images have always been amazing, back when I could hand hold the 1200 gram weight at arms length for zoom photography. Not so much now.
The filters would be for a range of lenses, cheaper for me than buying a filter for every lens. I'll have to look into them.
The filters would be for a range of lenses, cheaper for me than buying a filter for every lens. I'll have to look into them.
The clip in filters are not that cheap (a few/several hundred), but looking at your location, Lithgow, I'm not sure that you even need any filters- even in the centre of town your light pollution reading (SQM) is 20.99 !!!!!!!! or 0.432mcd/m^2 according to LightpollutionMapInfo World Atlas 2015. Travel a few kilometers out of town and it would be even better. Bearing in mind that a perfectly dark sky is around 0.171 mcd/m^2 your area is VERY DARK. As you can see from my signature line, my area is MUCH brighter than that.
