Mirrorless Night Sky Photography, Milky Way and Perseids

Discussion in 'Astrophotography' started by robcee, Aug 12, 2016.

  1. robcee

    robcee Mu-43 Veteran

    330
    Jan 10, 2016
    Toronto
    Rob Campbell
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  2. HRC2016

    HRC2016 Mu-43 Regular

    99
    Dec 6, 2016
    Hi Rob,
    Your article is just what I've been looking for.
    I have the Oly 12-40.
    Are there any inexpensive primes that you'd recommend for a beginner?
     
  3. Web-Betty

    Web-Betty Mu-43 Top Veteran Subscribing Member

    868
    Jun 16, 2013
    Denver
    Melissa
    Wonderful! I've been putting off trying night sky shots until we head up to the mountains.

    Is it worth trying night shots in a neighborhood with a few surrounding street lights?
     
  4. robcee

    robcee Mu-43 Veteran

    330
    Jan 10, 2016
    Toronto
    Rob Campbell
    I haven't used it, but the Rokinon/Samyang 12mm f2 lens gets pretty solid reviews. They're manual focus, but for shooting stars that's not really a problem. Focus once and leave it.

    Absolutely! Exposing to the right can still get a lot of star detail when you adjust in lightroom (or whatever software you're using). It won't look like much on preview in camera, especially if you're metering around +3.0EV, but get it into your software and decrease exposure, increase contrast and some stars should show up.

    Can't hurt to try it. :)
     
  5. HRC2016

    HRC2016 Mu-43 Regular

    99
    Dec 6, 2016
    Betty, I live in an urban area that has a lot of light pollution. There are a couple of large parks nearby that I visit to avoid streetlights, but I don't go alone due to transients who camp out there and nocturnal wildlife.
     
  6. HRC2016

    HRC2016 Mu-43 Regular

    99
    Dec 6, 2016
    Thanks Rob, I had my eye on that lens.
     
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  7. Levster

    Levster Mu-43 Top Veteran Subscribing Member

    I haven't read the whole blog yet, only got as far as the camera settings. From my experience an ISO of 400-800 is the maximum that I'd go to in order to minimise dark noise. I wouldn't go anywhere near ISO3200.

    There's a good article here comparing the E-M5 and E-M1 sensors at different ISOs and exposure lengths:

    wrotniak.net: Dark Noise in Olympus E-M5 and E-M1

    It is much better to stack multiple ISO400-800 images than artificially amplify the signal using ISO3200. You can see in the above example that noise at ISO400 is almost non-existent but noise at ISO3200 is substantially worse (it also shows that you really shouldn't use an E-M1 for long exposure shots!). I'd also avoid using the Panasonic 16MP sensors as they are poor at minimising long exposure noise too.
     
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  8. Levster

    Levster Mu-43 Top Veteran Subscribing Member

    "ISO3200 happens to be the largest workable ISO on the Olympus and Micro Four Thirds cameras before the sensor goes into boost mode (yes, I know it doesn’t say that on the screen, but trust me), so it has the best noise characteristics for long exposures"

    This isn't true, all ISO does in digital photography is amplify the signal generated when photons hit the sensor. Using too high an ISO (amplification) boosts both the noise and useful signal. The sensor receives the same number of photos regardless if the ISO setting, but either way the image will need some boosting to bring out the dim stars. Using ISO400-800 (depends on camera) provides the maximum amount of in camera amplification before the noise starts to become an issue. I had a link somewhere that listed Olympus cameras and their optimum ISO setting to minimise long exposure noise, I'll need to delve into the belly of the Internet to find it again.

    I like the rest of the blog! I'd also recommend a tracking mount to avoid star trails, these can be found for £200 and upwards on the used market.
     
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  9. robcee

    robcee Mu-43 Veteran

    330
    Jan 10, 2016
    Toronto
    Rob Campbell
    You're right, that boosted ISO adds a lot of noise to an image. Unfortunately, for dark sky photography, that's the easiest way to get to an image with a lot of dim objects in it.

    I'd consider doing a "Part 2" of that blog post and talking about stacking, but it's more difficult, and is more about using software than photography.

    I'm agreeing with you, in principle. The highest ISO I'd use on the EM1 is around 800 if I'm looking for detail, but 3200 produces a usable dark sky image for me, using the techniques I describe. If you have a better way, feel free to use it and post some examples.

    I'd love to get one of those star trackers, or better still, an actual tracking mount, but haven't put aside the money for one yet. Someday!

    Thanks for the feedback! :)
     
  10. robcee

    robcee Mu-43 Veteran

    330
    Jan 10, 2016
    Toronto
    Rob Campbell
    oh, another thing about sensor noise, the EM1 really isn't great for dark sky photography because the sensor becomes so noisy past 30s exposures. (edit: The linked article you included was a good analysis) I'm hoping the EM1mk2 performs better there and early reports say that it does. I just haven't seen any examples yet. Oddly, the original EM5 was far better at long exposure photography and markedly better than later versions, even. I'm kind of sad I sold mine.

    cheers!
     
    Last edited: Jul 17, 2017
  11. wjiang

    wjiang Mu-43 Hall of Famer Subscribing Member

    On the current m4/3 sensors 3200 is the highest unboosted ISO. At this ISO and below there is a different gain path in the hardware which does make a difference. For wide field stuff, I've had more success with images at ISO3200 than I've had with extreme pushing of lower ISO shots (for a fixed maximum exposure time to avoid trails). Stacking in both cases helps a lot - I'd say it's almost mandatory for this sensor format.
     
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  12. Levster

    Levster Mu-43 Top Veteran Subscribing Member

    Including landscape makes things more difficult! I only shoot nebula and galaxies so I don't have an issue stacking lots of shots because there is no static point of reference to worry about. I want to try a combination of a stacked Milky Way and a foreground object, which I'll try the next time I go camping. I use a Skywatcher Star Adventurer which also has a landscape mode where it tracks at 1/2 of the speed to try to give a bit more exposure without seeing obvious star trails, but this must start to blur the foreground at some point.
     
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  13. robcee

    robcee Mu-43 Veteran

    330
    Jan 10, 2016
    Toronto
    Rob Campbell
    yeah, I've struggled with landscape in my astro shots before. With some different exposure settings, lowering ISO, and shooting slower exposures, I can get a decently exposed ground shot and mask it into my night sky scene. It breaks down if there's any motion on the ground or harsh lighting that don't take the mask well.

    I've been eyeballing those Skywatcher trackers for awhile now. I think I have one in my Amazon wishlist waiting for the right combination of too many beers and an itchy mouse button. :)
     
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  14. cdd29

    cdd29 Mu-43 Rookie

    24
    Jun 11, 2017
    For your long exposures, are you using any kind of a tacking mount (ioptron, etc.)?
     
  15. robcee

    robcee Mu-43 Veteran

    330
    Jan 10, 2016
    Toronto
    Rob Campbell
    I'm not, no. I talk about setting exposure times to match focal length in the post to minimize blur. The rule of thumb is wider = longer. 12mm at 20s, 8mm can go as long as 30-40s with minimal star trails. By 40mm, you only get around 8-10s for a clean shot. That's why a fast aperture and high ISO are so important.
     
  16. robcee

    robcee Mu-43 Veteran

    330
    Jan 10, 2016
    Toronto
    Rob Campbell
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