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   goatsarah (goatsarah@thegoatery.dyndns.org)'s status on Friday, 10-May-2024 16:27:58 JST goatsarah

   • Neil Brown

   @neil Ta! Have thermos full of Yorkshire Tea, will travel.

   Star trails is 15 minute exposure + 15 minutes for dark frame subtraction. Had someone driven past in the first 15 minutes, it would have wrecked it. So remote up there that nobody did.

   • Embed this notice
     goatsarah (goatsarah@thegoatery.dyndns.org)'s status on Friday, 10-May-2024 17:13:30 JST goatsarah

     in reply to

     • Neil Brown
     • Andrew Zonenberg

     @azonenberg @neil Fuji XE-4, TTArtisan 7.5mm fisheye. Don’t know the aperture because it was pitch black and it’s a manual lens, so not recorded, but probably about f/4. ISO 160, tripod (obviously).

     Basically, drop the iso as low as possible, as long as the camera is able to subtract hot pixels, etc (which the Fuji is).

     And pray nobody drives past in that 15 minutes, because it’ll wreck it.

   • Embed this notice
     Andrew Zonenberg (azonenberg@ioc.exchange)'s status on Friday, 10-May-2024 17:13:31 JST Andrew Zonenberg

     in reply to

     • Neil Brown

     @goatsarah @neil 15 minute single exposure? Wow. What ISO/aperture?

     Most of my night work to date has been much shorter (few second) high ISO exposures, which are easier to get but also have much worse SNR.

   • Embed this notice
     goatsarah (goatsarah@thegoatery.dyndns.org)'s status on Friday, 10-May-2024 17:23:27 JST goatsarah

     in reply to

     • Neil Brown
     • zip
     @zip @neil The red is the tail lights of my car which was parked nearby with its side lights on, so I didn’t fall over and break my neck! The red illumination was not sufficient for me to see it with the naked eye, so when it turned up in the photo it was a pleasant surprise!
   • Embed this notice
     zip (zip@wandering.shop)'s status on Friday, 10-May-2024 17:23:28 JST zip

     in reply to

     • Neil Brown

     @goatsarah @neil dark frame subtraction?

     also i like how the exposure is so long that the trees are lit up eerily by what i assume is a red LED

   • Embed this notice
     goatsarah (goatsarah@thegoatery.dyndns.org)'s status on Friday, 10-May-2024 17:36:52 JST goatsarah

     in reply to

     • Neil Brown
     • zip
     @neil @zip Also, the yellow in the sky is not light pollution. It’s sunlight. I started the exposure at the end of the dregs-end of twilight and it was pitch black by the time it was finished.
   • Embed this notice
     goatsarah (goatsarah@thegoatery.dyndns.org)'s status on Friday, 10-May-2024 17:52:48 JST goatsarah

     in reply to

     • Neil Brown
     • Andrew Zonenberg

     @azonenberg @neil It’s a manual focus lens. I zoomed in to pixel level on the viewfinder and turned the focus ring until the streetlights 50km away were single points of light.

     Not easy because the viewfinder image was super noisy.

     Autofocus generally has no chance in those kinds of conditions. The other one is a 14mm autofocus lens but that’s only a 1 minute exposure and there was enough contrast left between the sky and the foliage to get an autofocus lock.

   • Embed this notice
     Andrew Zonenberg (azonenberg@ioc.exchange)'s status on Friday, 10-May-2024 17:52:49 JST Andrew Zonenberg

     in reply to

     • Neil Brown

     @goatsarah @neil Interesting, your camera does dark frame correction internally? I thought that was pretty much always done in post.

     Also, do you have any tips on focusing for these shots? I find with my Sony lenses "run to the end stop" is actually a little past the true "infinity" focus point, and every time I try manual focusing on stars I get it slightly off.

   • Embed this notice
     goatsarah (goatsarah@thegoatery.dyndns.org)'s status on Friday, 10-May-2024 17:58:05 JST goatsarah

     in reply to

     • Neil Brown
     • Andrew Zonenberg
     @neil @azonenberg I will say that I have ruined attempts before because of the same end-stop problem. It worked better when I turned the focus peaking off in the viewfinder because it was getting in the way.
   • Embed this notice
     goatsarah (goatsarah@thegoatery.dyndns.org)'s status on Friday, 10-May-2024 18:03:20 JST goatsarah

     in reply to

     • Neil Brown
     • zip

     @zip @neil The dark frame subtraction is an option on the Fuji X cameras. After the shot, it closes the shutter and takes another exposure of the same length, but in pitch black.

     It then subtracts the second from the first, eliminating stuck pixels, a certain amount of background noise, etc.

   • Embed this notice
     zip (zip@wandering.shop)'s status on Friday, 10-May-2024 19:48:14 JST zip

     in reply to

     @goatsarah that's super neat!

     goatsarah likes this.
   • Embed this notice
     goatsarah (goatsarah@thegoatery.dyndns.org)'s status on Friday, 10-May-2024 19:53:28 JST goatsarah

     in reply to

     • Neil Brown
     • Andrew Zonenberg
     @azonenberg @neil city lights are brighter than stars, if there are any in frame.
   • Embed this notice
     Andrew Zonenberg (azonenberg@ioc.exchange)'s status on Friday, 10-May-2024 19:53:29 JST Andrew Zonenberg

     in reply to

     • Neil Brown

     @goatsarah @neil Oh, yeah I didn't even attempt AF because I knew it'd get nowhere.

     That's pretty much what I've done, zoom in as far as I can on the EVF and twiddle the focus ring until the stars stop getting smaller. But yeah, noise makes that tricky. I guess I just need to practice more.

   • Embed this notice
     Andrew Zonenberg (azonenberg@ioc.exchange)'s status on Friday, 10-May-2024 20:03:57 JST Andrew Zonenberg

     in reply to

     • Neil Brown

     @goatsarah @neil

     Here's a few examples of otherwise-nice shots I lost due to this.

     I've mostly been able to take camera/tripod motion out of the equation by setting a ~5 second self timer, pressing the shutter button, then stepping away and letting the vibrations damp out before the exposure starts. So this blur should be all defocus.

   • Embed this notice
     goatsarah (goatsarah@thegoatery.dyndns.org)'s status on Friday, 10-May-2024 20:03:57 JST goatsarah

     in reply to

     • Neil Brown
     • Andrew Zonenberg
     @azonenberg @neil Yeah. Maybe stop down the aperture to f/8? Might help. Longer exposure needed though.
   • Embed this notice
     Marcos Dione (mdione@en.osm.town)'s status on Monday, 13-May-2024 01:55:02 JST Marcos Dione

     in reply to

     • Neil Brown
     • Andrew Zonenberg

     @azonenberg @goatsarah @neil lenses need that extra, post infinity 'reach' to do the autofocusing. Not sure if any of them actually have the infinity properly marked; none of the few ones I have/had had it. My current one has something that doesn't feel very accurate. Looking at manual focus lenses, they implement a similar cursor, but most seem to have the extra info of FoD, which make hyper focusing easier.

     I use a similar technique to what @goatsarah explained. I mostly use Jupiter.

     goatsarah likes this.