# Playing with HDR - Questions about night HDR



## pgowder (Aug 31, 2009)

I've started playing with HDR.  

Here are my first few:
HDR - a set on Flickr

Not the most interested subjects, but wanted to play with the technique.

I also tried a few at night.  The noise was terrible!  

Are there some tips for that?

Also I've seen some shots of fireworks using HDR.  How is that done with the long exposure?


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## pgowder (Aug 31, 2009)

Also on this one:






The wood on our roof is a light blue.  How can I get that to be a more true blue?  In this it turned grey.


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## manaheim (Aug 31, 2009)

This HDR thing is like some kind of virus lately.


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## Jaszek (Aug 31, 2009)

manaheim said:


> This HDR thing is like some kind of virus lately.


I'm afraid it's starting to become a pandemic. At least I got an "HDR Shot" so I think I'm mostly immune to it. Might try an HDR from time to time, but if it doesn't work out I just dump it.


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## manaheim (Aug 31, 2009)

Jaszek said:


> I'm afraid it's starting to become a pandemic. At least I got an "HDR Shot" so I think I'm mostly immune to it. Might try an HDR from time to time, but if it doesn't work out I just dump it.


 
Certainly don't care that people do it, but it boggles me to see people do it when it seems totally pointless.  Like folks just don't even know why you should be doing it to begin with, but they heard it was what all the cool kids were doing, so they dive in.

(no offense, OP... just that your images are generally those that don't benefit a TON from HDR/tonemapping... admittedly SOME... (mainly in the shadows under the deck, for example), but really not enough to warrant the effort, IMO)


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## Stormin (Aug 31, 2009)

manaheim said:


> This HDR thing is like some kind of virus lately.



I'm going to say that it's more like Crack in the eighties, Meth in the nineties. HDR is the new drug of choice for the youth these days.

To the OP, it all has to do with bringing out details that you would not have seen if the image weren't tonemapped. There's so very little variation that you don't need it.


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## pgowder (Sep 1, 2009)

manaheim said:


> Jaszek said:
> 
> 
> > I'm afraid it's starting to become a pandemic. At least I got an "HDR Shot" so I think I'm mostly immune to it. Might try an HDR from time to time, but if it doesn't work out I just dump it.
> ...



I agree these weren't great HDR candidates.  Like I said in my first post I'm trying to just learn the technique and the software.


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## pgowder (Sep 1, 2009)

Does anyone have answers to the questions I asked?


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## manaheim (Sep 1, 2009)

1. Use noise reduction software like Noise Ninja to reduce noise.

2. I assume an HDR of a firework would be done by taking a raw image, creating 3-4 exposures of the firework from the single image and then using them to create a "fake" HDR. (if there is such a thing)


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## pgowder (Sep 1, 2009)

manaheim said:


> 1. Use noise reduction software like Noise Ninja to reduce noise.
> 
> 2. I assume an HDR of a firework would be done by taking a raw image, creating 3-4 exposures of the firework from the single image and then using them to create a "fake" HDR. (if there is such a thing)



1.  So after you combine the images take it into NN or run the 3 photos into it before?

2.  How does that work?  Just save the 1 image as 3 separate images with different exposure settings?


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## manaheim (Sep 1, 2009)

1. Yes (though photomatix does have some NR in it... though it only seems to work "kinda")

2. Essentially, yes. Crank your exposure up and down in the RAW settings.

btw, interestingly I don't think most people notice or care much about noise in HDR/tonemapped images... I think there's so much obvious difference from a "usual" photograph that people glaze right over it. I've never corrected the noise in any of my HDRs.


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## pgowder (Sep 1, 2009)

manaheim said:


> btw, interestingly I don't think most people notice or care much about noise in HDR/tonemapped images... I think there's so much obvious difference from a "usual" photograph that people glaze right over it. I've never corrected the noise in any of my HDRs.



The ones I did at night made the sky look like sandpaper!


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## manaheim (Sep 1, 2009)

pgowder said:


> manaheim said:
> 
> 
> > btw, interestingly I don't think most people notice or care much about noise in HDR/tonemapped images... I think there's so much obvious difference from a "usual" photograph that people glaze right over it. I've never corrected the noise in any of my HDRs.
> ...


 
hm... i supposed if you had an underexposed shot that might occur given that your darker shots would be noisier, but...

Honestly, I dunno why you'd be doing an HDR at night anyway.


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## pgowder (Sep 1, 2009)

manaheim said:


> pgowder said:
> 
> 
> > manaheim said:
> ...



HDR at night - here is my inspiration for trying it:
Disney World


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## Dwig (Sep 1, 2009)

pgowder said:


> I also tried a few at night.  The noise was terrible!
> Are there some tips for that?



1. Always use the lowest ISO if at all possible. Raising the ISO defeats the purpose of HDR since it limits the tonal range captured in any one of the individual shots. 

2. Be careful not to boost the shadow detail excessively. You need to expose properly so that the "shadow" shot captures the desired detail without significant boosting.

Failing to follow these rules will lead to a significant increase in noise.



> Also I've seen some shots of fireworks using HDR.  How is that done with the long exposure?



Usually the fireworks themselves exist in only one of the shots. The HDR processing is used primarily for the background skyline or foreground. The only way to get multiple images of the fireworks in the HDR stack is to grenerate multiple versions from a single RAW original with different conversion settings.


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## pgowder (Sep 1, 2009)

Dwig said:


> pgowder said:
> 
> 
> > I also tried a few at night.  The noise was terrible!
> ...


Thanks for the advice!


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## manaheim (Sep 1, 2009)

Oh hey, Dwig knew the answer on the firework one.  Interesting!  Thanks, Dwig!


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