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Thread: Milky Way / Night Sky with Medium Format

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    Milky Way / Night Sky with Medium Format

    I'm curious to compare experiences with others shooting the night sky with medium format equipment. I previously did a couple of test shots with an IQ-260 but I'm now using the IQ-3100. My goal is to be able to print crystal clear, noise free images up to 48 inches across.

    I've experimented with three approaches:

    1: ISO 1600 for 30 seconds @ f/4.0

    2: ISO 1600 for 30 seconds @ f/4.0 with tracking and image stacking in Photoshop

    3: ISO 400 for 4 minutes @ f/4.0 with tracking

    Of the three, option #3 gives me the best results, but is the most cumbersome to use. Each exposure take 8 minutes, you have to photograph the foreground separately without tracking, and you have to have a good view of the North Star for best alignment. The length of the exposure time also makes stitched panoramas much more challenging so I have not explored that yet.

    I'm using the Sky-Watcher Star Adventurer tracking mount along with the optional equatorial mount. I chose it because it offers an 11 pound payload capacity and has an integral alignment scope. I've not had any problems with it handling the XF / IQ-3100 with the 35mm LS lens, even when it's mounted as shown, though this position puts a lot of torque on the mount and it does sag a little. I'm planning to buy or make an angle bracket to position the camera more on top of the unit. The only real drawback I've found is that the alignment scope is built into the central axis of the mount so you have to align the mount before you mount the camera. If anything shifts then you have to remove the camera and ballhead to re-align the setup. I haven't tried tracking longer than 4 minutes, but I've had very good results at 4 minutes.

    I've used the P1 28mm FP, 35mm LS and 150mm LS lens. The 28mm is noticeably better than the 28mm, especially as far as chromatic and coma aberrations are concerned. Focus can be a challenge with any of the lenses since they don't have a hard stop exactly at infinity.

    I'm still very undecided about post processing. Nearly all Milky Way photos I see online have been processed very heavily to really bring out the galactic center. They're dramatic, but not representative of what you actually see. On the other hand, the purpose of photography is to show what you cannot see, so maybe that's OK too.

    It also seems that the "right" amount of processing to boost contrast and saturation varies with the target resolution and print size. Smaller and lower resolution images seem to need more processing. When the tracking mount is set up correctly the stars are all rendered as pin points of light, so it seems to take more of a contrast boost to bring them out, especially at lower resolution usage. With non-tracked exposures the short star trail helps to highlight the stars at low resolution, but they definitely show streaks when enlarged.

    I've mostly just done test shots near home, but I'll be leaving in a couple of days for the Western US and hope to do some more serious night photography.

    I'm curious what approaches others are using and what we can learn from each other.


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    Re: Milky Way / Night Sky with Medium Format

    Out of curiosity, which of your 3 methods did you use for the image you posted? I'm yet to try and milky way photography with MF but would like to in the coming months....

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    Re: Milky Way / Night Sky with Medium Format

    The sample was ISO 400 for 4 minutes @ f/4.5 with the 28mm FP lens blended (roughly) with the foreground.
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    Re: Milky Way / Night Sky with Medium Format

    Seeing the weight of the XF & 35mm LS cantilevered out like that inspired me to make an angled bracket to better center the load over the drive and tripod.

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    Re: Milky Way / Night Sky with Medium Format

    I've used the P1 28mm FP, 35mm LS and 150mm LS lens. The 28mm is noticeably better than the 28mm, especially as far as chromatic and coma aberrations are concerned. Focus can be a challenge with any of the lenses since they don't have a hard stop exactly at infinity.

    This is interesting. I'm curious. Is that supposed to be, the 28mm lens is better than the 35mm...? Or..

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    Re: Milky Way / Night Sky with Medium Format

    Quote Originally Posted by waynelake View Post
    This is interesting. I'm curious. Is that supposed to be, the 28mm lens is better than the 35mm...? Or..
    Sorry for the typo. The 35mm is better than the 28mm.
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    Re: Milky Way / Night Sky with Medium Format

    If you shoot tracked then it would be best to shoot from an open area with as least obstacles as possible - it makes the blending work much easier and allows you to choose more creative foreground. But this will be like if one downloads some mega high resolution Milky Way materials from NASA's website and do the composition.

    Note that the XF+ body won't allow you to disable darkframe NR countdown so it may be painful to wait for each frame of long exposure.

    Generally you get way better end results if you shoot with a Nikon D810A + 24mm f1.4G lens wide open, in six directions, each with multiple frames, stacked and stitched in post-processing. That's more number of pixels, better signal-to-noise ratio, wider angle of view, as well as better representation of the H-Alpha colors, without having to carry the heavy tracking mount.

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    Senior Member Ed Hurst's Avatar
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    Re: Milky Way / Night Sky with Medium Format

    Hi Craig,

    Firstly, thanks for the thread - and the lovely shot. Certainly shows what a clean, crisp result can be achieved with a tracker.

    I generally shoot with a 645Z set to ISO 6400 and f4 for 15-20 secs for the sky - blended with ISO 800 frames (over several minutes) for the foreground; panos are common. No tracker. That approach is certainly easier without a tracker of course, since there is less of an issue at the horizon.

    My processing has tended to concentrate on the fantasy - an effect I have liked but am beginning to see as over-done. I expect to produce more realistic processing in future.

    Anyway, here are a few examples.

    [IMG]Australia Telescope Compact Array by Ed Hurst, on Flickr[/IMG]

    [IMG]Milky Way rising over Palm Beach and Barrenjoey Head by Ed Hurst, on Flickr[/IMG]

    [IMG]PanoFromFilesIMGP5115-21And5368-73V7Step10FlatsRGBSMALL-L by Ed Hurst, on Flickr[/IMG]

    [IMG]Pretty Beach by Ed Hurst, on Flickr[/IMG]

    [IMG]IMGP9607Step7SSsRGBSMALL-L by Ed Hurst, on Flickr[/IMG]

    [IMG]_IMG3761Step4SSsRGBSMALL by Ed Hurst, on Flickr[/IMG]

    [IMG]_IMG3640Step2SSsRGBSMALL by Ed Hurst, on Flickr[/IMG]

    [IMG]PanoFromFilesIMGP9872And75And78And81And84(ForLeftS ideOnly)Step5sRGBCropSMALL-L by Ed Hurst, on Flickr[/IMG]
    Ed Hurst, www.spiffingpics.com
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    Senior Member Ed Hurst's Avatar
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    Re: Milky Way / Night Sky with Medium Format

    A few more here for reference:

    [IMG]Narrabri 1 by Ed Hurst, on Flickr[/IMG]

    [IMG]Narrabri 2 by Ed Hurst, on Flickr[/IMG]

    [IMG]Narrabri 3 by Ed Hurst, on Flickr[/IMG]
    Ed Hurst, www.spiffingpics.com
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    Re: Milky Way / Night Sky with Medium Format

    Quote Originally Posted by Ed Hurst View Post
    I generally shoot with a 645Z set to ISO 6400 and f4 for 15-20 secs for the sky - blended with ISO 800 frames (over several minutes) for the foreground;
    Nice and stunning images there!

    Though the red cast in the shadow for long exposure at high ISO could have been drastically improved if you picked the Nikon D810A instead of an ordinary sensor, not to mention that faster wide angles at f/1.4 are available to choose.
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    Re: Milky Way / Night Sky with Medium Format

    Thanks for sharing Ed. Love the shots.
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    Re: Milky Way / Night Sky with Medium Format

    I have yet to capture what I think of as my "ideal" night sky photo, but this is what I think I've learned about using medium format for night sky photos. I realize most people aren't using medium format cameras for the night sky, but this thread isn't about alternatives to medium format. My intent is to share what we've collectively learned about using medium format.

    Focusing can be a challenge and the IQ3100 live view isn't good enough to show individual stars for focusing. I have set the hyperfocal tool for each lens so that the hyperfocal distance is at infinity and I've now assigned the front button to go to the hyperfocal distance, so now focusing is a snap.

    I've done a few more comparisons of shooting at high ISO and stacking versus lower ISO for a longer exposure and continue to find that ISO 400 is a good balance between speed and noise and gives me a better result than I get with stacking.

    I'm continuing to use the tracking mount. For perfect tracking you do need a view of the north star for polar alignment, but since I'm usually using a wide angle lens (28mm or 35mm) I can get it close enough just using my iPhone.

    Sensor resolution is so great that when I have stars in focus they are very small pinpoints. One of the challenges that presents is making sure they're visible at different resolution. For low res online usage I usually need to bump up the stars with some combination of sharpening, clarity or Photoshop's Maximum filter. For large, native-size prints they look good with less manipulation.

    I'm still struggling with dynamic range. The Milky Way likes a fairly long exposure, say 4 or 5 minutes, but that tends to blow out individual stars. The result is that I loose the relative size and colors of the stars. Keeping exposure to around 2 minutes seems to do better for the stars but underexposes the Milky Way for the way I like it to render. I may end up needing to do some form of HDR stacking to optimize both.

    Oddly I find that using medium format and the tracking mount creates some of these issues. I've also done some nigh sky photos with my Sony a6000, both with and without the tracking mount as well as with the IQ3100 without the tracking mount. Lower resolution cameras seem to render the individual stars relatively larger compared to the frame since, for instance, a 4 pixel dot is a larger percentage of the frame. Not tracking also renders the stars quite a bit larger, even for relatively short exposures of 15 to 30 seconds. Some of the issues I'm trying to perfect sort-of disappear when you use lower resolution equipment and/or shoot without tracking, but I don't find the overall quality to be as good as the potential with tracking.

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    Re: Milky Way / Night Sky with Medium Format

    Beautiful Ed!

    We'll be heading into New Mexico later this month to shoot the Large Array at night with the new IQ1-100 as well as an old ghost town.
    Don Libby
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    Re: Milky Way / Night Sky with Medium Format

    Hi Craig:

    Nice shot for sure. I can't speak to the MF for night work, as I choose a different platform (K1) and love it.

    Curious, with the wide retro focus lenses, 28mm and 35mm, when you track them, do you have the same issues I have run into with 15mm to 20mm on 35mm? in that the Milky Way needs to be as close to center as possible other wise you will still get trails and blur of the M Way.

    Still might have to try tracking the IQ100 sometime next year, as I agree with you that tracking provides a lot more overall, clarity, depth, and look/feel to the M way. It's actually pretty amazing.

    Paul C

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    Re: Milky Way / Night Sky with Medium Format

    With tracking I don't generally get star trails unless the mount isn't aligned properly. The bigger issue seems to be chromatic and coma aberrations, especially with the 28mm. Here is a link to a full size JPEG looking southeast with minimal processing in C1. C1 doesn't remove the chromatic aberration but Lightroom does.

    http://www.craigstocksarts.com/CF004454.jpg

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    Re: Milky Way / Night Sky with Medium Format

    I should probably title this "The Resolution Dilemma." I find that the high resolution of the IQ3100 + tracking makes some aspects more difficult. Since stars are rendered closer to pinpoints just a couple pixels across they start to look like noise and I also start to loose differentiation between brighter and dimmer stars. The result is an unnatural look with more stars showing than are visible and the stars we're used to seeing are lost in the field. Shooting with higher ISO without tracking hides that problem since it smears the stars and makes them more visible. The result actually looks better at low resolution, but at large print resolution you see the short star trails.

    Here's an example from the other night showing the difference without and with tracking, bot full frame and at 100%. All JPEGs are 1600 pixels across. The full frame without tracking looks better, but the 100% shows the obvious star trails. Taken with the IQ3100 and SK 35LS, ISO 1600, 30 seconds @ f/3.5. Just basic C1 adjustments. Yes, 30 seconds is probably too long based on the 400 rule but even at 1/2 the length the star trails would be pretty visible.

    My solution is to apply a combination of filters in Photoshop to enhance the brighter stars so they stand out. I turn the star layer into a smart object and then Cmd(Ctrl)-J to create a copy. Turn off the upper layer and apply two smart filters to the bottom, a 3 pixel Minimum filter to "turn off" the dim stars and then a 6-8 pixel Maximum filter to enhance the remaining stars. Apply a 6 pixel Gaussian blur. Then turn on the upper layer and set it to Lighten blending mode to bring back the dim stars. You can control how big you want the bright stars by varying the Maximum filter radius. Be sure the filters are set to preserve Roundness.

    I've also attached two images showing the Big Dipper without and with the added processing.

    Has anyone else found a better way?






    Last edited by Craig Stocks; 20th October 2016 at 13:51.

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    Re: Milky Way / Night Sky with Medium Format

    Hi Craig,

    Interesting dilemma indeed.

    curious, you mention applying a min and max filter. Can you elaborate on that just a bit? I understand how to run a min and max stack mode on a smart object, but not as a filter.

    Also you mention a star layer, are you creating a smart object on just one layer?

    Thanks
    Paul C

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    Re: Milky Way / Night Sky with Medium Format

    The Minimum and Maximum filters are found under "Other" filters. The minimum filter expands dark area and the maximum filter expands white areas. So, the minimum filter "turns off" the smaller and dimmer stars but leaves remnants of the larger stars. Then the maximum filter only sees the remnants and enlarges them into sharp round dots. The final blur filter takes the sharp edge off. The second layer is a copy of the original star layer and Lighten blend mode just puts back the dim stars without affecting the enhanced stars. I apply them as smart filters so they're nondestructive but you can also simply apply them to a layer.

    My sky layer is separate from the foreground layer. Since I'm using a tracking mount the sky is sharp but the foreground is blurred by the tracking motion. I shoot at least two frames, one with tracking for the sky and one without tracking for the foreground. The big advantage of tracking is I can shoot at ISO 400 with a 4 minute exposure and get sky images I can print 40 inches wide without worrying about noise.

    There's as side of me that says this is cheating, but you could say the same thing about stacking, noise reduction or long exposures in general. The result, to me, is a more realistic looking sky that is more like what I experienced.
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    Re: Milky Way / Night Sky with Medium Format

    Hi Craig

    Thanks. I am also a huge believer in tracking, via the Pentax K1. IMO the best solution. Has a bit of trouble with retro focus wides, but the results speak for themselves. I also usually track in the ISO 400 to 800 range, 2 to 4 minutes. Average is about 2 minutes for me.

    Again thanks for sharing the workflow as I am always looking for a better way.

    Paul C

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