Third party prime for night sky photography/Auroras

Aussie shooter

@brett.guy.photography
Dec 6, 2016
435
431
I am looking at getting a fast prime for milky way and aurora photography. Running a 7d2 atm so thinking something that will give me around a 20mm equivalent on the crop sensor but obviously will fit a FF when I go in that direction. Any suggestions on a decent affordable option?
 

Joules

EOS RP
Jul 16, 2017
275
183
Hamburg, Germany
I use the Samyang 16mm 2.0 on my 80D, because the FF part was not important to me. But 25mm equivalent can be a bit narrow at times. It's a lens only for APS-C though. There's also the Irix 15mm 2.4. Wasn't available when I made my purchase so I have no idea what the differences in optical quality between the two are. But it is a Full Frame lens. Price wise they are similar, the Irix comes in a Version with lower built quality but identical optics.

I guess apart from the affordable bit the obvious choice is the Sigma 14mm 1.8. Faster and wider than both of the other lenses, also Full Frame compatible and with AF and electronics. If it wasn't so expensive, it would've been my choice.
 
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Joules

EOS RP
Jul 16, 2017
275
183
Hamburg, Germany
Yeah. I am really think 1.8 minimum and preferably 1.4. That would go a long way to make up for the lower SnR of the 7d2 sensor.
Depending on what your preferences are, you might also want to consider a portable sky tracker. The Sigma 14mm 1.8 gives you not even a two stop advantage over the cheaper options. And it is really quite a lot more expensive for such a specialized piece of kit. For that money, you can get some dedicated Astro gear.

Something like a Skywatcher Star Adventurer, Vixen Polarize or Fornax Lightrack II, to name a few, allows you to significantly increase your exposure speed. This offers far higher exposure gains than just 2 stops and therefore basically transforms all you lenses to ASTRO lenses. Could also get an Omegon LX2, a tiny tracker with an affordable price that doesn't need batteries.

The downside is additional weight to carry around and some effort setting up on location.
 

Aussie shooter

@brett.guy.photography
Dec 6, 2016
435
431
Depending on what your preferences are, you might also want to consider a portable sky tracker. The Sigma 14mm 1.8 gives you not even a two stop advantage over the cheaper options. And it is really quite a lot more expensive for such a specialized piece of kit. For that money, you can get some dedicated Astro gear.

Something like a Skywatcher Star Adventurer, Vixen Polarize or Fornax Lightrack II, to name a few, allows you to significantly increase your exposure speed. This offers far higher exposure gains than just 2 stops and therefore basically transforms all you lenses to ASTRO lenses. Could also get an Omegon LX2, a tiny tracker with an affordable price that doesn't need batteries.

The downside is additional weight to carry around and some effort setting up on location.
Thanks for the info but probably not the best option for aurora shots.
 

Joules

EOS RP
Jul 16, 2017
275
183
Hamburg, Germany
Thanks for the info but probably not the best option for aurora shots.
Good point. Tracking only helps with stars and deep sky objects.

I have no experience with Aurora. I thought that they are bright enough so that aperture doesn't matter as much. But they also move faster, so exposure time becomes a greater issue.

I just bought a Fornax Lightrack recently to get better night skies and eventually start doing deep sky stuff when I've got polar alignment figured out reliably and accurately. Seeing how uncertain the future of cameras is right now, I thought it made more sense for me to by a lower priced lens for the gear I use (16mm 2.0 for the 80D) now and a more expensive bit of Equipment that will work with anything I might use in the future, regardless of whether that will be APS-C or FF, DSLR or Mirror less, Canon or something else.

So I thought I'd mention the option.

But just in terms of quality, there's not much you can do wrong by going with an Art lens, especially for something that requires manual focus anyway, like anything Astro does. My Samyang 16mm 2.0 is quite sharp wide open, but it looks pretty poor when comparing it directly to my Sigma 35mm 1.4 Art. Looking at TDPs tool, the story doesn't seem to change much when comparing it to the 14mm 2.4 full frame lens:


It's too bad that throwing in affordable into the requirements usually means making some compromise. Astro is such a niche and unfortunately Canon hasn't done much to serve it in the past.

For Canon DSLR, all options I'm aware of have been listed here. There are more for mirror less and other systsms, but that doesn't help for your 7DII.
 
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