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I like taking city photographs, like monuments or squares, with a starry sky. Since the square/monument is usually well illuminated, I take advantage of HDR with a short exposure for the illuminated things and a long one for the sky. The final result has always some little problem I would like to avoid:

  • the sky shot has flares I don't want: some areas have brighter "dark blue" and this results in an unaesthetic result, if not retouched
  • I want to take as many stars as possible
  • Noisy sky if I set high ISO, but more flares if I set a lower one (and more exposition time)

an example of what I'm talking about:

enter image description here

What changes can I make in order to improve the points I've listed above?

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  • 1
    Welcome to Photo SE; I've made a small tweak to this (good) question to stop it being purely about changing settings, as there may be other things you can change which would improve things. Hope that's okay, if not feel free to revert my changes.
    – Philip Kendall
    yesterday
  • 2
    If you are taking pictures with a tripod you could take a second shot covering with a board the lower part of the picture and then stack the two frames.
    – FluidCode
    yesterday
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    in Madrid, it's the Debod Temple en.wikipedia.org/wiki/Temple_of_Debod
    – Bertuz
    yesterday
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    Personally, I wouldn't add too many stars. The amount of stars looks pretty reasonable to me given the lighting of the sky. If I were to see the whole milky way in your picture, my mind would go "yet another photoshop act". 20 hours ago
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    What about a graduated nd filter? Might work for you 18 hours ago

2 Answers 2

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Your basic problem is that most stars are much dimmer than the parts of your scene lit up by artificial lighting. Combined with the diffusing properties of air and all of the particulates and moisture floating around in it, there is a haze from the brighter light reflecting off the stuff in the air and it is drowning out the very dim light from all except the brightest stars or planets.

Since you can't increase the amount of light provided by the stars, your only option to balance the two is to reduce the brightness of the artificial illumination in the scene. Is there a time later at night when the flood lights are turned off and you can shoot the scene while only illuminating the monuments and buildings using techniques such as light painting or controlled flashes. The advantage to either one is that the stars can be exposed for longer while the light you provide for the foreground subjects can be much shorter in duration.

The only other option if you want a darker sky with stars showing in it is to shoot a separate frame for the sky away from the light pollution of the artificial lighting and combine the two shots after the fact. HDR won't really give optimal results in this case because it will pull up the very dim diffused light that is reflected off the moisture, dust, and other particulates in the air along with the stars and that diffused light will continue to limit how many stars are bright enough to shine through the haze.

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  • I think a sodium line filter for the star shot may also help in some situations, though sodium lamps are disappearing and don’t seem to dominate the example scene.
    – Seb
    yesterday
  • If you want to keep things lined up the same way, e.g. on a tripod, take 2 shots in the same location, one with a very long exposure and one short. The buildings and ground will be washed out in the first and the stars will be invisible in the second, but at least they're lined up properly, which should make compositing easier. yesterday
  • Might be some benefit to use something as a gobo on the building during a long exposure. That is, use a piece of paper or some other object suitably shaped to block the light from the building from hitting the lens while exposing the sky, making sure to pull it away in time to allow some exposure of the building. Still wind up with reflected haze issues, though. yesterday
  • @DarrelHoffman Please put that in an answer so it may be voted upon. You're not taking into account the diffusing properties of the air and the particles in it. Longer exposures will most likely result in brighter haze that still overpowers all but the brightest stars.
    – Michael C
    12 hours ago
  • @jeffronicus That sounds more like an answer than a comment to this different answer.
    – Michael C
    12 hours ago
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Notwithstanding the existing answers to try fix it at source, another option is to use something like Aurora HDR, which you can use on your separate shots or even the composite. The closer to the original RAW files you give it, though, the more it can work it.

This is what I managed to squeeze out of it using your uploaded jpg.
I added a little bit of burn & dodge in Photoshop.
Not brilliant, but not too shabby…

enter image description here

Click for full size

The warm glow we'll call artistic interpretation ;) I couldn't really get any detail back into the trees , but I managed to rescue a fair bit back into the stonework. From the RAW I'd bet you can get a lot more out of the stars too.

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