Astro-work lens

What are you folks happy with for astro work? Just curious. I've used several of the lenses in my Sig.
I'm looking to take advantage of the clear winter skies and wondering if one of these fast rokinon 1.4 primes would be worthwhile. Other recommendations? Or should I just stick with what I have?

Rokinon 14mm f2.8

Cheap and works great.

Look at Mikey Mack's flickr account, I believe he uses the Rokinon 14mm a lot. His flickr account should be all the convincing you need.

Since you're on crop the Rokinon 10/2.8 or any of the Tokina 11-xx's would be a little better for the wide field stuff. Although you could buy a tracker and use it with all of your lenses. You could do a 2 shot composite with your 12-24/4 with one shot tracked and the other not tracked to capture the foreground.

To get a proper exposure of the milky way in a dark location, you are looking at 28 seconds f2.8 ISO 6400 with a wide end of a Tokina 11-16/2.8. This goes to 56 seconds with your 12-24/4. This would however give star trails if untracked since you needs to follow the 500 rule which is 500/FL * crop factor. Lonelyspeck.com gives a lot of details for this.

When you put the 12-24/4 on a tracker, you could easily get a 4 minute exposure without star trails. So now instead of using ISO 12800 at f4 12mm for 30 seconds, you could drop that ISO down to 1600 and get a much cleaner picture. Combine a 10/2.8 with a tracker and you are talking about ISO 800 and you can probably push a tracker harder, but I've not used one in wide field applications.

Look at my gallery. The two of comet Lovejoy were shot with my 135/2 and the Ioptron sky tracker. Your Tammy 70-300 with a tracker could do pretty well too given dark sky conditions and if you stacked images in deep sky stacker or another stacker program, it would be even cleaner.

Frodge wrote in post #17846697
What are you folks happy with for astro work? Just curious. I've used several of the lenses in my Sig.
I'm looking to take advantage of the clear winter skies and wondering if one of these fast rokinon 1.4 primes would be worthwhile. Other recommendations? Or should I just stick with what I have?

Heya,

The Samyang/Rokinon 24mm F1.4 lens is ideal (on full frame) for wide field astro. It's sharp wide open and most importantly has really good coma control, which the 24L II can't even match. The Rokinon 14mm F2.8 is of course a common and less expensive ultrawide that is great both on full frame and APS-C alike, fast enough for general long exposure, and sharp wide open. If you're on APS-C, the Rokinon 16mm F2 is a great new addition, giving another stop of speed advantage.

Really though, a tracker is the better way to get light if you really want to do wide field astro. It allows any lens to work well for it. Allows lower ISO. Overall get cleaner images. Removes shutter duration and focal lengths as limiting factors. The Sky Watcher Star Adventurer would be what I suggest starting out.

Very best,

MalVeauX wrote in post #17847558
The Sky Watcher Star Adventurer would be what I suggest starting out.

Did you ever get your skytracker to take a load again? Send it in for the $60 repair? Or did you go and get the above? It looks a little nicer and can handle a heavier load.

FEChariot wrote in post #17847637
Did you ever get your skytracker to take a load again? Send it in for the $60 repair? Or did you go and get the above? It looks a little nicer and can handle a heavier load.

Heya,

I've not sent my iOptron back to them yet for repair. I need to.

Regardless of my iOptron working again, I will likely move to the SkyWatcher soon. It will handle longer lenses better without getting a full on $1k+ EQ tracker.

Very best,

Thanks for all these responses. Its a lot to consider. Do you guys think imbbetter off getting a faster lens or that star tracker? The star tracker from what I'm reading is a good solution...I appreciate it.

Frodge wrote in post #17848075
Thanks for all these responses. Its a lot to consider. Do you guys think imbbetter off getting a faster lens or that star tracker? The star tracker from what I'm reading is a good solution...I appreciate it.

Heya,

Well, I guess it really depends on what you want to do.

If you want to have less to carry out into the field, do shorter exposures, use a lot higher ISO, and either do a lot of clean up, or be ok with lots of noise, or do a lot of post-work with stacking, then getting a fast wide lens is a good idea. If you're heavily interested in incorporating foreground & wide field astro in one shot, without doing composites, then this is the way to go. Again though, you will be completely limited by shutter length relative to focal length if you do not want star trails. This means really high ISO, even at F1.4, you will still be pushing higher ISO. This isn't an issue if you are ok with some noise and proficient with post-work to clean it up. But this only will be useful if going for wide field work that allows 20~30 second exposures. Even 24mm is too "long" on an APS-C for that exposure length. While the F1.4 helps get more light to make up for the lack of shutter length and high ISO use, it's still not ideal. 16mm on APS-C will get you a solid 20 seconds before trails occur. This is where the Rokinon 16mm F2 really shines, you get the speed of F2, and the benefit of 20 second exposure length. Plus it's wider field to get a large structure like the Milky Way instead of just a section of it.

Otherwise, a tracker liberates you from the limitation of shutter duration, liberates you from needing super fast glass, liberates you from needing high ISO performance, and allows any old lens & camera to soak up enough light at lower ISO to get a clean image and you can use a lot more focal lengths, such as wide angle, all the way to telephoto (200mm even). The tracker does a lot more for you in the long run if you want to really capture the night sky and get more interested in more than just wide field and get more into deep space objects. The trade off? Time mostly. You will be doing longer exposures with this, 2 minutes... 4 minutes... etc. It takes more time. But the result is cleaner, brighter, and sharper images from basically anything you put on it. One other thing to consider is that because the tracker moves, foreground objects or horizons will move too, blurring. So trackers are for the sky, and only the sky. To combine the sky and foreground, you would need to do a composite, where you do whatever exposure of the sky and then do a separate non-tracked exposure of the foreground and simply layer them into a composite. So it depends on your needs.

Both methods require post-processing work beyond just basic stuff, both need substantial effort to get the kinds of images you see floating around here of dark skies, bright stars and objects and lots of color.

For cost, I would always recommend a tracker over better camera & lens equipment.

While a 6D + Samyang 24mm F1.4 is a really fantastic way to do night sky & foreground in one shot, it's also $1500. And still will not yield a cleaner image than something from a tracker.

Also, if you really want to do night sky without a tracker, and you're spending that kind of money, you're way better off saving a bit more and going for a Sony A7S series. The ISO performance topples the 6D by several stops for this purpose which will give more flexibility with focal length options. And I'd still pair it with the Samyang 24mm F1.4.

But for cost, a $450 tracker setup is simply going to give you more freedom of equipment while getting you cleaner, sharp, bright images.

***************

Here's some examples from a basic T4i and various lenses on a cheap $300 tracker.

EF 85mm F1.8, what's important to note, is that this is a two minute single exposure at ISO 400 on a crop.

IMAGE LINK: https://flic.kr/p/kPpD​Si

IMAGE LINK: https://flic.kr/p/kRz9​wv

IMAGE LINK: https://flic.kr/p/nqb5​2w

IMAGE LINK: https://flic.kr/p/nS8k​eV

IMAGE LINK: https://flic.kr/p/nzCy​TM

IMAGE LINK: https://flic.kr/p/nVtz​yC

IMAGE LINK: https://flic.kr/p/nS8k​WM

IMAGE LINK: https://flic.kr/p/nTUK​5c

That's a lot to soak in. I've never used a tracker before, but it sounds like the answer long term. I've been doing some reading on night photography and am becoming really interested in it. I really appreciate all your help Martin, it gives me a good starting place. Ideally I'd love to get a 6d a fast lens and a tracker and have it all at once. Lol. From what I read on some of these sites, certain lenses aren't as sharp wide open so they recommend stopping down, which totally defeats the purpose of a fast lens. The more I absorb your last greatly informative post, the more a good tracker makes sense. Does anyone have a link on how to do a composite? Its funny this was brought up, because I need to do this for another project o thought up. I need to separate the sky from the foreground and stitch together the two different exposures. Have a good day guys.
BTW..nice shots!

Quick question. What is the pitfall of the 24mm rokinon 1.4 on aspc vs the 14mm 2.8? I re-read your post several times and the implication is not to use the 24mm 1.4 on crop, but to rather use the 14mm. OR am I reading this wrong?

24 on crop would give you 13 second exposure with out star trails which is pretty good at 1.4. However I have found that 24 on crop is just not really wide enough for Milky Way landscape shots and too wide for anything deep sky. Andromeda is 5 times larger in the sky than the moon and it takes 200 or so on crop of not a little more. I have shot that with my 135/2 just to get the speed of f2 but I cropped quite a bit. If you wanted to do a multi shot pano of the Milkey way or just a section of it, then the 24 would be a good pick.

how about modifying the camera. I have thought about modifying a 70D I have to full spectrum and then adding a cls filter for astrowork. If you get more nebular light in then would you get a better short photo before star trails start or would that necessitate a tracker?

I must admit the thought of trying to take a photo of a nebula with my 300 2.8L on a converted 70D with a cls filter sounds pretty fun. Of course I'd rather not spend all that money if I'm wrong.

(conversion 300/star tracker 400/clip filter 150)

Frodge wrote in post #17848747
Quick question. What is the pitfall of the 24mm rokinon 1.4 on aspc vs the 14mm 2.8? I re-read your post several times and the implication is not to use the 24mm 1.4 on crop, but to rather use the 14mm. OR am I reading this wrong?

Heya,

It's due to the crop factor and how it will alter perceived angles of an arc. Basically less portion of the arc is in the frame, so something passing through the frame will be perceived as moving faster relative to it, so it will trail faster, compared to a wider view, where the arc is a greater distance. So a 24mm on APS-C can go to about 13 seconds of exposure time, before trails become obvious and visible. 11~12 seconds is a safer bet to avoid the beginning of star trails. This is due to the angle of view relative to the arc. On full frame, that same 24mm has a wider angle, so it will be able to go to about 21 seconds before trails begin, or more likely 20 seconds to be safe.

If using a tracker, it doesn't matter either way, and you can expose for as long as you want, 4~5 minutes easily.

Very best,

Luxx wrote in post #17848886
how about modifying the camera. I have thought about modifying a 70D I have to full spectrum and then adding a cls filter for astrowork. If you get more nebular light in then would you get a better short photo before star trails start or would that necessitate a tracker?

I must admit the thought of trying to take a photo of a nebula with my 300 2.8L on a converted 70D with a cls filter sounds pretty fun. Of course I'd rather not spend all that money if I'm wrong.

(conversion 300/star tracker 400/clip filter 150)

At 300mm on crop you are limited to about a 1 second exposure which really limits you. Canon did produce the 60Da in addition to the 60D so full spectrum would have advantages, but you're still going to want a tracker.

Thanks Fechariot and malveaux for all the this and information.I think I will be looking into a tracker. Thanks a bunch guys!