@Neil Brown 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.
@Andrew Zonenberg @Neil Brown Fuji XE-4, TTArtisan 7.5mm fisheye. Donât know the aperture because it was pitch black and itâs 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 itâll wreck it.
@zip (happy halloween 2024!) @Neil Brown The red is the tail lights of my car which was parked nearby with its side lights on, so I didnât 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!
@Neil Brown Point camera at sparse source of photons. Leave shutter open for a boringly long time. Go home, see what youâve managed to get in Adobe Lightroom.
There are two, what I assume to be Starlink, satellites in it if you look carefully.
@Neil Brown @zip (happy halloween 2024!) Also, the yellow in the sky is not light pollution. Itâs 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.
@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.
@Andrew Zonenberg @Neil Brown Itâs 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 thatâs only a 1 minute exposure and there was enough contrast left between the sky and the foliage to get an autofocus lock.
@Neil Brown @Andrew Zonenberg 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.
@zip (happy halloween 2024!) @Neil Brown 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.
@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.
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.
You can get Yorkshire Tea in Portugal? I'm so envy. So far I haven't found it in Nederlanden. Fortunately, my wife is traveling every few months to UK and brings a big bag. @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.
Sarah Brown
Unknown parent • •@Neil Brown 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.
Andrew Zonenberg
in reply to Sarah Brown • • •@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.
zip
in reply to Sarah Brown • • •@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
Sarah Brown
in reply to Andrew Zonenberg • •@Andrew Zonenberg @Neil Brown Fuji XE-4, TTArtisan 7.5mm fisheye. Donât know the aperture because it was pitch black and itâs 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 itâll wreck it.
Sarah Brown
in reply to zip • •Sarah Brown
Unknown parent • •@Neil Brown Point camera at sparse source of photons. Leave shutter open for a boringly long time. Go home, see what youâve managed to get in Adobe Lightroom.
There are two, what I assume to be Starlink, satellites in it if you look carefully.
Sarah Brown
in reply to Sarah Brown • •Sarah Brown
in reply to Sarah Brown • •@Neil Brown Annnyway, at this level the camera is pretty much counting single photons.
And, of course, all the colours are still there. The human eye just doesnât see colour below a certain intensity.
But cameras do.
Andrew Zonenberg
in reply to Sarah Brown • • •@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.
Sarah Brown
in reply to Andrew Zonenberg • •@Andrew Zonenberg @Neil Brown Itâs 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 thatâs only a 1 minute exposure and there was enough contrast left between the sky and the foliage to get an autofocus lock.
Sarah Brown
in reply to Sarah Brown • •Sarah Brown
in reply to zip • •@zip (happy halloween 2024!) @Neil Brown 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.
Andrew Zonenberg
in reply to Sarah Brown • • •@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.
Andrew Zonenberg
in reply to Sarah Brown • • •@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.
zip
in reply to Sarah Brown • • •Sarah Brown likes this.
Agnieszka R. TurczyĆska
in reply to Sarah Brown • • •So far I haven't found it in Nederlanden. Fortunately, my wife is traveling every few months to UK and brings a big bag.
@neil
Sarah Brown
in reply to Agnieszka R. TurczyĆska • •Sarah Brown
in reply to Andrew Zonenberg • •Agnieszka R. TurczyĆska
in reply to Sarah Brown • • •@neil
Sarah Brown
in reply to Andrew Zonenberg • •Marcos Dione
in reply to Andrew Zonenberg • • •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.
Sarah Brown likes this.
Marcos Dione
in reply to Andrew Zonenberg • • •Astrophotography with RawTherapee, Clarkvision.com
clarkvision.com