Night Shot HDRs

Discussion in 'Digital Photography' started by rhomsy, Mar 2, 2008.

  1. rhomsy macrumors regular

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    Jul 6, 2007
    #1
    I'm interested in doing City scene HDRs at night. Some of these scenes have lots of range, and reflection which can benefit from HDR. However, the low light can cause problems because you have to crank the ISO and this results in noise. Plus, when you run images with noise through an HDR program like photomatix, it results in amplified noise and a completely useless photo.

    How do you guys create nighttime cityscape HDRs? If I kept my ISO at 100, I'd get nothing. Do you run it through noise software first. I don't have a particularly noisy camera (Canon 40D), but I still find these shots impossible.

    The most promising solution that I was investigating was the use of image stacking software to remove the noise, and then create the HDR. I downloaded the trial for PhotoAcute. With PhotoAcute, you can shoot your bracketed as normal, but instead of one set of bracketed shots, you would shoot like 10 shots. You can run each set of +2/0ev/-2 through PhotoAcute, and it will stack the images and remove the noise because of the principle that noise is random. It actually works amazingly well. However, when I take the resulting noise free TIF files and run them through photomatix, it doesn't work.

    After spending my entire Saturday trying to figure this out, I'm completely frustrated and need help. How do you guys do it?
     
  2. Lightglance.com macrumors member

    Lightglance.com

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  3. rhomsy thread starter macrumors regular

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    #3

    Well I do use a tripod. As far as the shutter speed goes, you are saying that I can't use my cameras auto bracketing....which is fine if that's the answer. My auto bracketing only works in aperture priority. I of course opened the aperture fully, but the shots were still coming out too dark. Maybe I'll throw it into manual and make my own bracketed shots. Of course that involves touching the camera between shots, which is something that I don't like to do.

    Tell me, if I was to manually create my bracketed shots, how do you know which shutter speeds to use to get +/- 2? I suppose I'd keep shooting until I figure out the normal exposure, but then it's a matter of calculation to get +/- two stops. Since my shutter speed settings are in less than one stop increments, I don't know how to do that.
     
  4. onomatopoeia macrumors 6502

    onomatopoeia

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    Dec 9, 2007
    #4
    Well, converting the RAW files to TIF is one problem as you are losing the dynamic range found in each RAW file. You might as well be creating HDR's from JPG. Certainly, you can use TIF or JPG but it's not "really" HDR unless you are using RAW.

    I somewhat disagree with your sentiment that night cityscapes contain a great deal of range. In absolute terms that is correct (pitch black to bright light) but HDR often works best where enough light is visible to offer the subtle tonal gradations from dark to light. While every scene is different dusk would generally be a better time than night for most HDR work.
     
  5. JDR macrumors regular

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    #5
    Valdore, paging Valdore, please make your way to the white courtesy telephone....:D
     
  6. valdore macrumors 65816

    valdore

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    #6
    Haha... :)

    For nighttime urban landscapes, I'll keep the camera in ISO 100, tripod mounted with a shutter release cable, and whether I'm going with multiple source images straight from the camera or just from a single RAW, I will often run my source images through Noiseware Standard, which is a $50 plugin for Photoshop (I use CS3), prior to merging into HDR in Photomatix.

    I like to shoot in Aperture Priority for this, keeping a constant aperture setting, with the shutter speed being the variable; this maintains consistent depth of field.

    I have applied Noiseware to both TIFFs and JPEGs (my source images after splitting them from the RAW) and have not had any problems doing so with either method.

    As for manual bracketing, I've done it this way before. If you have a solid and sturdy tripod and it is not too windy outside, simply adjust the shutter speed by scrolling your little wheel.

    Worth mentioning - if the noise is bad enough, it never hurts to run your mid-range and over-exposed sources through the noise filter two or three times (I've always found twice will suffice), and then after merging in Photomatix, take that final output image back into Photoshop and apply the noise filter once again - this time to the end product.

    Edit - I use a Canon 5D (full frame) which performs great at keeping the noise to a minimum, so that might help me out quite a bit too.
     
  7. onomatopoeia macrumors 6502

    onomatopoeia

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    #7
    So, you convert the RAW files to TIFF and then merge and tone map the TIFF in Photomatix? Is that what you're saying?

    If so, that's not HDR. It's a tone mapped TIFF image. But perhaps I'm reading your post wrong.
     
  8. valdore macrumors 65816

    valdore

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    #8
    Using multiple source images bracketed straight out of the camera, you can shoot JPEG and merge them to HDR, and it is still HDR. I used to do it all the time before I began shooting RAW.

    Now, HDR from a single JPEG isn't really HDR - you are correct. However HDR from multiple JPEGs is HDR.
     
  9. bocomo macrumors 6502

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    New York
    #9
    you can also load multiple images for noise reduction in photoshop cs3

    russell brown (www.russellbrown.com) even has a free script for it to run automatically from bridge (which is what i use to kill the noise in my night images). i find a stack of 6 works well for iso 400 on my camera...

    HDR is a composite of multiple shots encompassing a higher dynamic range than is possible with a single exposure-no matter if they are jpegs, raw, tiff, etc.

    each individual image's dynamic range is inconsequential-it is the sum/combination of them all that is HDR
     
  10. onomatopoeia macrumors 6502

    onomatopoeia

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    #10
    I guess I am splitting hairs.
    Still, the sum of 3 RAW images yields much greater dynamic range than the sum of 3 TIFF or JPG images.
     
  11. bocomo macrumors 6502

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    #11

    that is splitting hairs as one more jpeg capture (totaling 4 instead of 3) would increase the dynamic range beyond what the 3 raw files captured

    HDR is just a whole new way of thinking

    :)
     
  12. rhomsy thread starter macrumors regular

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    Jul 6, 2007
    #12
    I'm still having significant problems producing a Night Cityscape HDR. I went down to the waterfront in Boston last night, and I was able to get a few bracketed shots before multiple police cruisers came and forced me to leave. Evidently, they thought I was dropping ocean mines with my Canon 40D. Total morons.

    Anyway, the shots had some ships on the peaceful harbor water, with some strong multicolored reflections in the water. I thought this would make a great HDR. The problem was it didn't. I had my camera set at ISO 100, and I had an aperture of f/4 (which I should have had higher to get a greater depth of field, but I'm still learning), I took two sets of bracketed shots. One set with +/-2 and another with +/-1. I combined the images for 5 shots of -2, -1, 0, +1, +2. I used a tripod. The shutter speed ranged from a second or two, to 30 seconds. I did get a lens flare, but that's because I didn't have a lens hood (I'm learning and I need to buy one).

    The problem was that there was SIGNIFICANT banding on the HDR, especially on the reflections in the water. I took the RAW files and imported them into photomatix for processing. Should I be processing them prior to bringing them into photomatix. What is the proper workflow and technique for doing night HDRs.

    Thanks,
    Russ
     
  13. rhomsy thread starter macrumors regular

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    #13
    Here is the image after *trying* to tonemap it in Photomatix Pro

    [​IMG]
     
  14. rhomsy thread starter macrumors regular

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    #14
    Another disaster. Look at the banding on the side of the building, along with the rest of this total mess.

    [​IMG]
     
  15. Optimus Rhyme macrumors regular

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    London, UK
    #15
    Try posting the original file somewhere, or files if they were done with bracketing. Let other people try to do a version of it, and see if it's the photo, or just the settings. Someone could tell you the settings they used, if you like the picture more than yours.
     
  16. valdore macrumors 65816

    valdore

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    #16
    Just off hand, it looks like the Luminosity setting wasn't high enough - try at least 0 and experiment moving it higher.
     
  17. rhomsy thread starter macrumors regular

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    Jul 6, 2007
    #17
    Thanks Valdore. I love your work, and if my HDRs could only be half as good as yours I'd be happy. I'll try that out.

    I'm also wondering if the initial exposures on my shot were not done well. Does the heavy banding result from blow outs? Perhaps I should have brought all of the exposures down another stop. I guess this could be a basic photography problem more than an HDR problem. At what should I meter against for determining exposure in a night scene? The lights on a lamp post? Which metering mode is best? I was using Evaluative.....but then again, I really always leave it in Evaluative. I guess I'm a noob.

    Then again, maybe I'm just screwing up in photomatix. However, my daytime HDR's look pretty good.
     
  18. Optimus Rhyme macrumors regular

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    Oct 28, 2006
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    London, UK
    #18
    Any thought to posting the original file or files, depending how you do it? I'd love to try making an HDR of one of your shots you're unhappy with how it turns out, see if the settings I use on it work better for you.
     
  19. bocomo macrumors 6502

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    Jun 29, 2007
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    New York
    #19
    it looks like it's just a processing problem, not exposure. don't worry about metering at night as it's pretty useless. the exposures you make for HDR will have blown out highlights-no worries, that's part of the capture process and a vital part of HDR. remember, you are capturing a total brightness range, one that doesn't fit into what your camera can normally capture.

    the most common problem i see with HDR-Gone-Wrong is that the scene photographed wasn't a good candidate for HDR but the process was sort of forced on it. not saying that's the case here but it just might take a bit more adjusting in the tone mapping part of the process...
     

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