Viltrox 13mm for astro, done better? And quite possibly a thumbs up

In the thread below, I did tests, posted results, and I think I was wrong :-P. I hate doing tests like this, so bear with me; I'm not a shoot pictures of a brick wall type usually.

https://www.dpreview.com/forums/post/66883085

If you don't want to read any further, I have come to the conclusion that at f2.8, the Viltrox 13 mm that I have may well be the best choice for astro over my other lenses.

I lucked into some lack of cloud cover last night (Pacific Northwest) and did some more tests, and came to different conclusions **based on the lenses I have**, YMMV.

To make a long story short, I have with me at present: Laowa 9mm f2.8, Rokinon 12mmf2 (and a Samyang copy as well), Fuji 14mm f2.8, Samyang 14mm f2.8 (FF lens), Fuji 16mm f2.8. X-T5 is the camera.

After trying different things, I decided to be a bit more thorough, aim the camera at the same portion of the sky (my last test, I had to move around due to clouds), and try each lens at f2 if available, f2.8, and f4. 13 seconds exposure which it turns out may be too long for best results across the board, but it worked for these tests.

What I reported as field curvature issues on the Viltrox 13 was actually star movement in the corners which appeared to be radiating in towards the center simply because I was pointed mostly eastward and up some.

I ended up focusing on f2.8 as the sweet spot simply because f2 showed poor results in the corners on all my options.

However, I accidentally shot the Viltrox at f2.5, and it did okay there, so I will have to see where it actually breaks down. F2 was not good in the corners.

Other things I have noticed is that the Fuji 16 f2.8, and that Laowa 9mm both do reasonably well at f4 (images not included) as does the Rokinon 12., and in a pinch might be okay for some work at f2.8.  The Laowa has fierce vignetting as is known. My Fuji 14, sadly, shows coma even at f4.

Prior to this, I was using an X-T3, so I think the greater resolution may be showing some of the weaknesses of some lenses like the Rokinon 12.

Here are the boring pics, full size if you want to peep them. 50% JPG to reduce the size:

Laowa 9

Rokinon 12

Viltrox 13

Fuji 14

Samyang 14 f2.8

Fuji 16 f2.8

Thanks for the update. 
Again, if I could get out myself (and get clear skies) I’d be interested to see how the Viltrox performs at f2.8 against the 16-55 @16mm.

grey pilgrim wrote:

GMacF wrote:

Thanks for the update.
Again, if I could get out myself (and get clear skies) I’d be interested to see how the Viltrox performs at f2.8 against the 16-55 @16mm.

A lens I don't have, but I imagine the 16-55 makes a pretty fine astro lens at 16.

From 13 to 16 is a pretty sizable change in FOV. 16 needs a shorter exposure at all the same settings. I didn't do that with my 16 f2.8 here, but should have.

I also wonder how the 16 f1.4 does at f2.8 (another lens I don't have) or even the new 18 f1.4 even though that's fairly tight FOV for astro landscapes.

Doug

Yup, from my own experience, 16mm is pretty long for widefield astro work without some sort of tracking capability.  The length of exposure needed to bring out much in the way of detail at 16mm f/2.8 is almost certainly going to yield some rather unwelcome trailing, I would think (or excess noise at higher ISOs).  So, I'm not so sure that the 16-55 would be all that great for astro, hence I haven't really even tried it as yet.  Concerning the 16mm f/1.4, given the additional speed, it might be fast enough to give you a decent result with a shorter exposure.  Would be interested in seeing a sample from a test.

I'm on the fence on this lens hoping that it'll do better than the Rokinon 12mm. The absolutely best I have now is a Sony a7r3 with a Batis 18mm (equivalent to 12mm on APS-C). But now that I upgraded to the X-T5, i'd love to find a lens that comes close to that Batis; also, not carrying 2 bodies would be nice. I mostly stack but bought a small tracker last year.

I did try the 16-55mm mounted on the tracker and it was disappointing. 16mm is also too long for the kind of astro shots I like to do.

Did you try several copies, or was this your 1st lens you got? I wonder how is the copy variation with this lens.

zurubi wrote:

I'm on the fence on this lens hoping that it'll do better than the Rokinon 12mm. The absolutely best I have now is a Sony a7r3 with a Batis 18mm (equivalent to 12mm on APS-C). But now that I upgraded to the X-T5, i'd love to find a lens that comes close to that Batis; also, not carrying 2 bodies would be nice. I mostly stack but bought a small tracker last year.

I did try the 16-55mm mounted on the tracker and it was disappointing. 16mm is also too long for the kind of astro shots I like to do.

Did you try several copies, or was this your 1st lens you got? I wonder how is the copy variation with this lens.

Well, from all I’ve read here and many other places, the Rok 12 is one of the best widefield astro lenses out there, so not sure what your issue is with it.  With a tracker, I’m a bit surprised that the 16-55 didn’t perform fairly well, at least at 16mm.  Most of what I do these days is widefield starscape shots with no tracking, so I’m usually using the wide end of my 8-16 f/2.8 lens — which, BTW, is simply superb for that purpose.  25s exposures yield a fair amount of detail, and you can play around with different ISO settings to see which one gives you the best combination of detail and minimal noise.  Obviously, with a properly aligned tracker, you should be able to increase the exposure time and capture even more detail.  I can’t tell you and what point the noise would become a real issue with a longer exposure since I no longer have any tracking capability.

grey pilgrim wrote:

Jerry-astro wrote:

zurubi wrote:

I'm on the fence on this lens hoping that it'll do better than the Rokinon 12mm. The absolutely best I have now is a Sony a7r3 with a Batis 18mm (equivalent to 12mm on APS-C). But now that I upgraded to the X-T5, i'd love to find a lens that comes close to that Batis; also, not carrying 2 bodies would be nice. I mostly stack but bought a small tracker last year.

I did try the 16-55mm mounted on the tracker and it was disappointing. 16mm is also too long for the kind of astro shots I like to do.

Did you try several copies, or was this your 1st lens you got? I wonder how is the copy variation with this lens.

Well, from all I’ve read here and many other places, the Rok 12 is one of the best widefield astro lenses out there, so not sure what your issue is with it. With a tracker, I’m a bit surprised that the 16-55 didn’t perform fairly well, at least at 16mm. Most of what I do these days is widefield starscape shots with no tracking, so I’m usually using the wide end of my 8-16 f/2.8 lens — which, BTW, is simply superb for that purpose. 25s exposures yield a fair amount of detail, and you can play around with different ISO settings to see which one gives you the best combination of detail and minimal noise. Obviously, with a properly aligned tracker, you should be able to increase the exposure time and capture even more detail. I can’t tell you and what point the noise would become a real issue with a longer exposure since I no longer have any tracking capability.

I would have agreed with that assessment about the Ron 12 with the X-T3. I was always happy shooting it at f2.8. Now, with the X-T5, I am seeing significant coma at f2.8. Maybe the greater resolution is showing that up? Or maybe my technique needs a fine tuning.

The issue for me is lack of testing time here in the Pacific Northwest right now.

So far, it still looks like my copy of the Viltrox 13 is giving me better results at f2.8 than my two copies of the Rokinon/Samyang 12. Others have reported the Samyang 12 as great wide open with respect to coma. Mine are not. So, sample variation could be coming into play, or the testing conditions right now.

I did manage to get a 2 min tracked test of the Viltrox at f4, iso 200. Looked good. I tried other tacked shots where it became my polar alignment was off.

I've tried some stacking as well, but it looks like there were clouds hitting some of the edges which messed those tests up.

Either way, I am keeping the Viltrox; it has shown me enough to convince me at f2.8 it's a solid performer.

Doug

My Rokinon is fine+ for MW shots but not stellar. I actually never tried it since I bought the tracker so I should. I also never took the XT5 on an astro shoot since it's too new. Probably will rent that Viltrox to benchmark it against the others.

That Batis 18mm/2.8 FF is just phenomenal, so the bar is high....