Focusing Aurora

Discussion in 'Astrophotography' started by popcan, Apr 17, 2016.

  1. popcan

    popcan Mu-43 Regular

    62
    Aug 3, 2013
    image. image. image.


    I tried using my pan 12-35 2.8 on Aurora display a few nights ago- looking at the results I wonder if I'm getting the focus quite right? I wanted the foreground trees to be sharp, so I had pre focused on them. But in others' Aurora pics I have seen, the lights appear far better defined. Especially in the last pic, in a tighter shot.
    The lights seemed to be moving a lot also, so maybe this is the reason?
    Is there an optimum exposure duration to "freeze" the shimmering aspect of Aurora?
    These frames were at 2.8, between 6 and 8 seconds, ISO 800 - 1600.
     
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  2. wjiang

    wjiang Mu-43 Hall of Famer

    Aurorae will often move a lot, and since it looks somewhat close on the horizon the apparent movement will be reasonably large. I'd say anything longer than about 4 seconds is going to start looking noticeably blurred. If you're right under a very active one maybe even less. It's one area where m4/3 will find it really challenging - increasing exposure times with alignment and stacking doesn't work with aurorae like it does with plain astrophotography - you really have to jack the ISO up to get a reasonably high shutter speed, especially if you can't afford to shoot at f/1.8 due to lens or DoF limitations.
     
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  3. georgian82

    georgian82 Mu-43 Regular

    119
    Jan 17, 2014
    In focus or not, those are beautiful pictures! Great job
     
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  4. Levster

    Levster Mu-43 Top Veteran

    If you focus on the tree using f/2.8 then you're going to get a little bit of subject isolation, so the foreground would blur. I'm not sure how much of an issue it would be at the focal lengths that you're using. You could always take two shots and combine, then see if that looks better? One focusing on aurora and one focusing on tree.
     
  5. popcan

    popcan Mu-43 Regular

    62
    Aug 3, 2013
    Thanks - this is only the second time we've had an Aurora at the lake when I've been around to try getting some pictures. First time was a disaster, I had no idea what I was doing. Who knows when we'll get another display, but I'm learning a bit more each time.
     
  6. Levster

    Levster Mu-43 Top Veteran

    I'm jealous that you get to experience them! I'm a bit too far south to see them. I'd be very happy with your shots!
     
  7. tradesmith45

    tradesmith45 Mu-43 All-Pro

    Dec 13, 2012
    Oregon
    Hey Warren, good work & its such a privilege to have a location you can go to more than once for aurora. I'm envious!

    Looks like you got the focus ok but I'm seeing lots of noise for ISO 800-1600. That is certainly softening your images. What camera & NR software are using?

    Aurora, especially dim ones, are a big challenge for m43. If this is a subject you want to pursue, you may want to invest in different gear. Unfortunately newer m43 & Sony mirrorless cameras are showing worse hi ISO long exposure noise than some of the older cams. I've tested several & so far the original E-M5 is the best m43 for this subject. And IMHO f2 or faster lenses are a huge help for night work w/ m43 because it does so much to reduce sensor noise. They are also easier to focus than f2.8s at night (except for the M.Z 8mm f1.8 FE which has such a long focus through).

    I've done many night landscapes & find the resolution of the EVF & LCD have an impact on my focus success. The E-M5 m2 is so much better than the original E-M5. Even w/ mag live view, it can be pretty hard to know you've nailed it especially with focus by wire lenses. Haven't owned the Pana 12-35mm but my M.Z 12mm has only 1 MF ring position that hits infinity. I do a test capture & magnify it on the LCD too but that can also produce ambitious results.

    Practice night focusing on a pinpoint light source you have easy access to or star to learn your gear & do test shots you think are in focus. Then check them on a computer or tablet. I haven't tried using WiFi & my iPad for night shots yet but will.

    I checked the 12-35mm review over at LensTips & it has little coma & modest 9% astigmatism in the corners. So if you check focus at a corner, you might feel its out of focus when it isn't. But this is a problem for probably every lens you might use for nigh sky work.
     
  8. popcan

    popcan Mu-43 Regular

    62
    Aug 3, 2013
    Thanks for the reply tradesmith - I was using a GX8, pretty new to me still. But I also still have an original EM 5 I can try. PP in Lightroom, but I'm just getting to learn that too. Definately try some different exposure combinations next time!
     
  9. tradesmith45

    tradesmith45 Mu-43 All-Pro

    Dec 13, 2012
    Oregon
    The GX8 seems to be a very good camera but almost certainly has more noise than the old EM5. But the older OMD has a lower rez EVF so harder to focus.

    Check out DXO Optic Pro 10 for NR. It has given me the best NR results of the things I've tested including LR. Topaz has a new NR program out i haven't tried but have seen positive comments about it.

    Not sure where you're located but based on the images you've posted, one of the 12mm f2 m43 lenses would improve your images on either cam by providing more light. For far north locations, 12mm isn't wide enough however because the aurora can cover most of the sky. The new MZ 8mm f1.8 would produce terrific images. If you search for my aurora trip, you'll see images i got w/ the Kowa 8.5mm f2.8, another great lens but I had to use ISO 1600-3200.

    Good luck!

     
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  10. popcan

    popcan Mu-43 Regular

    62
    Aug 3, 2013
    I'm located in the South Cariboo Region of British Columbia, perched at about 3600' above sea level on the Fraser River Plateau. It's a very good spot for dark skies and little haze, but we are not really far enough north to see the Aurora very often. It's a treat when we do. I have in mind to also try some Milky Way captures. I have been eyeing the samyang/rokinon 12mm f2, and wondered how much difference the extra stop would make over my 2.8 zoom. Is the MZ 8mm 1.8 a fish eye? I will try to look at your pics for sure!
     
  11. tradesmith45

    tradesmith45 Mu-43 All-Pro

    Dec 13, 2012
    Oregon
    I'm much further south in Oregon. Did a study for a presentation to my camera club by searching Flickr & found low on the horizon/dim aurora can be captured even in S. Oregon about a dozen times a year. W/ your dark sky, you'll have far more opportunities. Watch for magnetic disturbance levels of Kp=>5.

    The E-M5 can make excellent aurora captures even w/ an f2.8 lens but all the m43 cameras will do much better @ f2. That extra stop will make a surprising difference if it allows use of ISO1600 instead of 3200.

    Yes, the MZ 8mm is a FE so really big FOV. All that FOV if useful for big aurora but will just contain lots of dark space if the aurora is small. Depending on your budget & given your location, I'd put large aperture ahead of large FOV. And the FE distortion may not be to your liking.

    The FE was not available for my Yukon trip last Sept so I took the excellent Kowa 8.5mm f2.8. If I was doing the trip today, not sure which I'd take. The FE would make the wonderful mountains so tiny. Not yet convinced FE is for me but right now its the ONLY f2 UWA choice we have. That's why I'm seriously considering a Fuji X to use the Sam 12mm f2 to get rectilinear f2 UWA. Plus Fuji has much less noise especially for long exposures.

     
  12. popcan

    popcan Mu-43 Regular

    62
    Aug 3, 2013
    After seeing your pics, and comparing with my feeble effort, I am convinced that my exposure is all wrong - as well as my focusing! Back to the drawing board!
    But I am not discouraged; I have only just begun to delve into astro-photos and have much to learn. It's quite challenging, testing both me and my equipment!
    I will def try with the EM5 body next time, or shoot with both to see how much difference there is in the way they capture.

    I should be at the lake for the next new moon in July (got a 2nd grandson coming the end of May, so I'll miss the beginning of June), and I hope to have a go at the Milky Way then.
    With luck, we will have some more Aurora too while I'm there, although it takes a fairly significant event to reach us, and typically we only have a handful of those a year, so it's very hit and miss.
    And then, of course, there is the small matter of random cloud cover. Is there an app for that yet? lol


    BTW, regarding Fuji X... what are the main points of interest to you there other than the option of mounting a UWA....more MP/larger sensor, lower noise, sexy looks? I must admit, the looks of that XPro2 appeals to an ex-Leica M4 owner.....
     
    Last edited: Apr 20, 2016
  13. tradesmith45

    tradesmith45 Mu-43 All-Pro

    Dec 13, 2012
    Oregon
    Sounds good. Congrats on the young one & best of luck at the lake.

    There are only three reasons for me to consider Fuji & several things that are not so good for me. The Sam 12mm f2 is one big plus. Other pluses are terrific noise performance especially for long exposures. Take a look over @ Brendan Davey's work on this - the Fuji is one of the best (thought not as good as a Sony A7s). There other advantage of the Fuji is going w/ it for day/night landscape kit will not add but about 0.5 lbs to my kit weight for backpacking. A FF kit adds a couple lbs.

    Haven't tried it yet so don't know how easy it will be to focus an X cam at night.

    Main downside is as yet there are no really stellar long tele options, nothing like what Oly offers. The new XF100-400 looks to be too soft for me at >300mm. So I'd keep the E-M1 & my ZD300 so 2 systems.

     
  14. Ctein

    Ctein Mu-43 Regular

    Dear Popcan,

    I think your pictures are entirely satisfactory. If this is your first effort, you did a very good job. Don't belittle yourself.

    Regarding your sharpness issues, that's just plain depth of field (or lack thereof) working against you. You can focus on the trees… or you can focus on the stars… but you won't get both tack sharp at the same time, unless you're at 12 mm, in which case you really shouldn't be seeing an obvious difference. Still, pick one or the other.

    As far as what's required to freeze the fine structure in aurora, that is incredibly difficult. I haven't seen anything other than image-intensified scientific photos that do that well. In all the wonderful, artistic photographs you find online, that fine structure is blurred out the same way it is in yours, even if it isn't obvious when you look at those other photographs.

    To give you an idea of the difficulty, I photographed these back in 1986 (on medium format ISO 400 film):

    Ctein's Online Gallery

    Exposure times for all of them were in the 5-10 second range, and they're showing structure (or lack thereof) similar to yours). There was one exception:

    http://ctein.com/Green_Curtain.jpg

    I photographed this one at one second, and it's showing a bit more of the filamentary structure.

    Unfortunately, that appears to have been a lucky fluke. The structures normally are not that stable. Two years ago I went to Yellowknife to photograph aurorae, and this is a one-second exposure from there:

    Blog326figure1

    (note: this is not typical of the photos I made there-- I cranked the ISO way up, 'cause Vivian couldn't hold still for more than a second under those conditions)

    It shows a little more structure than the 5-10 second exposures I made at the same time, but not really anything like what you could see with the naked eye. More discouragingly, I did a series of test exposures down to 1/4 second, and none of them were noticeably more detailed than the longer exposures. I think it's going to require an exposure of at least 1/10th of a second and possibly 1/30th (or even shorter!) to catch the fine structure. That is simply beyond the range of micro 4/3 equipment at present, unless you have an exceptionally bright (rare!) aurora.

    I'm going to be going back to Yellowknife this fall, and I'm going to rent a Nikon D810 and a Sigma 24mm f/1.4 lens. I'll do some tests ahead of time to make sure this is the right combo, but it may let me get down into that exposure range and still get an acceptable image.

    Mind you, I have no idea if it will be sufficient to show the fine structure. But, y'know, it's an experiment. And the reality is that you can do absolutely wonderful aurora photographs with a current micro 4/3 camera and a reasonably fast lens. I got a bunch of nice portfolio stuff my last trip (not on my website, yet, because I'm woefully behind).


    pax \ Ctein
    [ Please excuse any word-salad. MacSpeech in training! ]
    ======================================
    -- Ctein's Online Gallery Ctein's Online Gallery
    -- Digital Restorations Photos Restored Digitally by Ctein
    ======================================
     
    Last edited: Apr 23, 2016
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  15. popcan

    popcan Mu-43 Regular

    62
    Aug 3, 2013
    Thank you for the detailed reply Ctein, I particularly like the last pic - it's more along the lines of what I was hoping to capture. I guess maybe I have expectations higher than my current equipment is capable of?
    These pics weren't my very first effort - more like my third attempt. I'm sure there is plenty of room for improvement.
    I will continue to experiment, and probably will look into a faster/wider lens for this kind of photography.