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I currently have room for another option in the mid-wide range and I'm specifically targeting something around 300mm, the only criteria being decent F-ratios (Think F/2-3). Until I get a second rig I don't think adding another expensive telescope would be the best option for me at the moment, so I'm leaning towards camera lenses. Preferably Nikon F mount as that would be less of a hassle to adapt with my current equipment. I currently use a 2600MM, Esprit 100ED, Edge 8, Samyang 135 and a Rokinon 85. I've swapped to mostly Z-mount lenses for daytime photography so I don't have that many options left from my current selection of lenses. I've been considering a Nikon 300mm F/2.8D lens, I briefly looked at the Tokina ATX 300mm F/2.8 but I got mixed feelings about that one after going through some forum posts. I'm open to suggestions if anyone happens to have some experience with other alternatives as well. The idea is to use it wide open for narrowband at least, stopping down slightly with step down rings for broadband is an ok drawback. |
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| Nikon 300mm f/2.8 AFS, the more recent the better. I have a bunch of pictures in my profile, if you feel inclined to have a look. I only use it wide open. |
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And this is the test shot: https://www.astrobin.com/c8onpo/?nc=collection&nce=7793 |
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| Thank you! I'll have a look, the test image looks rather well! Shouldn't be too hard go get a copy on the used market sometime I reckon. |
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You mention narrow band. Even with say a 5nm filter, at f/2.8, you are likely going to experience some spectral shift. A 3nm filter is probably off the table. To avoid spectral shift (which can do funky things, like vignette the field and also attenuate the band signal), you might need an even wider NB filter, 8nm or thereabouts. If you are imaging under dark skies, this probably wouldn't be an issue...but, it might be if you are trying to image under light polluted skies. Fast NB is kind of an oxymoron...so make sure your plans for filters are indeed compatible with an f-ratio that fast. |
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| I have used the lens with the Optolong L-eNhance with rather good results and also the L-eXtreme with a bit more halos than the other. After pondering on what to stick to I decided to go for the L-eNhance as reasonable compromise (besides, I also use the L-eXtreme on the other rigs). L-Pro works well as I suspect similar filters. Any filter narrower than 5nm gets the chop unless is tailored for fast systems. |
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Jon Rista: I'm already doing F/2 with my Samyang 135, the Antlia 3nm filters works a treat - also the 4.5nm Edge one that I used to have but I believe those are recommended for faster than F/2.6 anyways. Those are the only filters I use though, so I'm sure other variations or brands might show some issues. I opted for the 3nm ones in the end since they accomodate all my scopes the best when all things are considered. As for LP it isn't a huge issue for me as I'm usually around B3 where I live. I appreciate the input though  |
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| C6/Hyperstar V4 = 300MM @ F2 and it covers APS-C. Plenty of examples in my portfolio, most recent submission of NGC1499 was with the F2 L-Extreme. I know you said camera lenses but I don't know of one that is going to give you a satisfactory result without a huge expense, that comes close to what my recommended option can achieve as it relates to quality and cost. |
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| Except it isn't a lens, is it? |
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andrea tasselli: ooh wow, i just realized that. Enlightening, thanks. |
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Jan Erik Vallestad:Jon Rista: Just to be clear...at f/2 with 3nm, you ARE experiencing spectral shift. That means your 3nm filter is costing you transmission the farther you get off the optical axis. This doesn't necessarily mean you lose all the transmission, but that as you move away from the center of the frame, the bandpass shifts and will eventually shift off the band at enough of an angle. The center of the field may appear fine. The periphery will probably appear more vignetted, and it can be difficult to clearly understand what you are losing in the band signal in the periphery of the field, but most likely you are losing something, and maybe a non-trivial something. |
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andrea tasselli: Wha... not a lens? (takes a closer look) What do you mea... (screams) |
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C6/Hyperstar V4 = 300MM @ F2 and it covers APS-C. Plenty of examples in my portfolio, most recent submission of NGC1499 was with the F2 L-Extreme. I know you said camera lenses but I don't know of one that is going to give you a satisfactory result without a huge expense, that comes close to what my recommended option can achieve as it relates to quality and cost. I have considered the Hyperstar for my Edge 8 before, or even a RASA, but I think I'm well enough equipped on the telescope side for now. But it's a great suggestion if a cheap C6 were to appear. The reason I haven't gotten a Hyperstar already is simply because I dread having to unmount my filters from my EFW and use a filter drawer. I would generally be open to telescope suggestions as well, but I could get a Nikon 300mm F/2.8D for less than $380 used which is hard to beat. I was kind of hoping some vintage manual lens could be a possible dark horse though |
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Jon Rista: I am aware of the theory, but Antlia still makes 3nm filters for specific high F-ratios above F/2.6, between F/2.6-3.5 and smaller F-ratios. I might be wrong but your statements might not be up to date as well. Unless you also claim that the manufacturer lie about the products they sell (Since you are already making claims about what I am experiencing)? My filters are specifically rated like this:  It says F/3, but it also says that they are tested to meet the requirement of a Hyperstar/RASA telescope which is at F/2. My usage of the Samyang 135mm at F/2 so far show no particular vignetting or anything else that I have noticed. I cant speak for what minimal loss actually means, but to me it seems good enough. What could make me stop down ever so slightly though is to improve star shapes. Plenty of people use fast optics and narrow NB filters with stellar results. As always I'm happy to be proven wrong and learn something new, but when my vendor sell me filters made for fast optics - I will use them on fast optics. But this is likely a topic on it's own and don't really belong in this thread as per my original post. If you have any recommendations that suit my request you are most welcome to share them. |
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I am aware of the theory, but Antlia still makes 3nm filters for specific high F-ratios above F/2.6, between F/2.6-3.5 and smaller F-ratios. I might be wrong but your statements might not be up to date as well. Unless you also claim that the manufacturer lie about the products they sell (Since you are already making claims about what I am experiencing)? So does Astronomik and Baader and I think Chroma as well. I have a set of the Astronomiks on order for my Tak Epsilon 130D (f3.3) and they are supposed to be good down to f 2.2.. Astronomik Max FR |
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| I tried to use antlia 3nm ha and oiii before with ASI533MM and hyperstar c8 390mm f1.9. Ha is ok, but oiii has halo. although you still can take picture. But it is so slow. I dont know, but in my opinion, it will slow like F/6-F/7. If you want to use, you should try badder's narrowband filter._ fast version. |
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I tried to use antlia 3nm ha and oiii before with ASI533MM and hyperstar c8 390mm f1.9. Ha is ok, but oiii has halo. although you still can take picture. But it is so slow. I dont know, but in my opinion, it will slow like F/6-F/7. If you want to use, you should try badder's narrowband filter._ fast version. I've been using the Antlia filters for a couple of years now (both 1.25" and 2") and I have yet to see halos on either the F/2 lens of the F/5.5 refractor I use. That also goes for the Oiii filters. So I disagree. Note that there are different versions of the 3nm filters available from Antlia as well. But again, this is not strictly on topic. I'm not asking for peoples different experiences with filter brands. |
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Bill McLaughlin:I am aware of the theory, but Antlia still makes 3nm filters for specific high F-ratios above F/2.6, between F/2.6-3.5 and smaller F-ratios. I might be wrong but your statements might not be up to date as well. Unless you also claim that the manufacturer lie about the products they sell (Since you are already making claims about what I am experiencing)? I've heard good things about them. Chroma was never on my list due to cost though, as far as I'm concerned the possible knive's edge quality difference isn't justified by the jump in cost.. I was just pointing out to the previous poster that, as far as I know, 3nm filters aren't necessarily unfit for fast optics. I only mentioned Antlia because that's what I've been using myself the past few years. I am very pleased with Antlia and how they perform though |
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Jan Erik Vallestad:Jon Rista: Ah! You are actually using one specifically designed for faster f-ratios. Sorry, I did not catch that previously. If that's the case, then you might be fine. F/2 is pretty darn fast, but more than that, the wider field is what is likely to create highly oblique angles of light for peripheral parts of the field. Its that angle of incidence that is the potential issue. I haven't actually tried to image with a wide lens at a fast f-ratio, so I can't speak directly to any experience here. I would just be wary of the potential consequences of spectral shift. If the lens was a narrower field, like a hyperstar, or something, then it wouldn't quite be the same...but the wide field of view means some pretty wide angles of light. |
