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Did You Hear Something Go Boom?

It's a holiday week here in the States, so no big lesson. Just a small one.

This is actually two images. They were combined by copying image two over image one in Photoshop. A new layer gets created. Since they were both from the same camera and precise alignment wasn't necessary, I didn't need to do anything else other than change the Blend mode to Lighten. Did some fireworks just go off in your head?

Bonus lesson: note that these fireworks aren't blown out (there are some small highlight blowout areas, which you'll never avoid), but the main elements are within proper exposure. Exposure is mostly determined by aperture, ISO, and distance to the fireworks. The closer you are, the more you probably need to stop down, especially if you're using long exposures as I was here. Don't get caught up in the fireworks display. Take an early exposure and evaluate it carefully. Note that in most programs the intensity of the fireworks will get higher, especially at the end, so if you start with overexposure, you're going to get a mess of blown values at the end.
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Banu Manubawa's profile photoEvan Spellman's profile photoDolores Perez's profile photoDavid Dennis's profile photo
15 comments
 
The firework detonations are nicely captured, but the streaky noisy background is a distraction - guess that's (comparatively) early digital technology for you :-(
 
This is a very instructive site not only for your posts Thom, but also for everyone's comments, that I have been following since I discovered it. This time I didn't understand what you said about exposure, but before going on I want to make clear that my intention is to be constructive and yet I fear that my English might not be good enough to convey that idea.
I do not consider ISO to be part of exposure. But that's a fight I won't start. I accept that everyone is different and has different ways of thinking depending on his/her backgrounds and for some including ISO as an exposure parameter might work well. For me, it's just the opposite. Now, including distance (I assume camera to subject distance) is a première. I would say that unless you go far enough so that the light trails get smaller than one pixel across, distance is irrelevant to exposure. That's why we know how to set the exposure to take a picture of the Moon, or the near and further away parts of a landscape all end up with the correct exposure (not depending on distance) as long as all receive the same amount of light. If the object being photographed is so far away that it is smaller than one pixel as is the case with most stars (the Sun being a fortunate exception) then this rule doesn't apply.
Do you have any evidence that the greater tendency to create blown outs from a short distance is linked to those becoming smaller than one pixel when you are further away? If not, what is your explanation?
 
Very timely :)   I was planning on trying my hand at fireworks for the first time with my new Nikon 1 and I very likely would have tried a fast shutter speed.  This stuff doesn't come second nature to me yet.  Getting exposure figured out early in the show is another thing that doesn't occur to me automatically. 

I really like the idea of compositing the fireworks pictures given how interchangable the backgrounds would be so I'll have to try that out.
 
+Vicente Fonseca Sorry, but ISO is a part of exposure. In particular, this is an example of when it is very, very important, as shutter speed generally is playing no role in the exposure. Put another way, you can't get a proper exposure without considering ISO in this case.

I always get grief about my distance comment, but I'll stick by it. Technically, there shouldn't be a difference. However, practically, there usually is. That's mostly because of the smoke that starts to build and drift during most shows. However, even without that, I tend to find that it's a bit like lightning: when you're close to the bolt, you get large areas of blowout unless you stop down. When you're far from the bolt you don't care as much about the blowout as they're smaller streaks and not broad areas. Try it. Get as close as you can and as far as you can from big fireworks like this: I'll be very surprised if you use the same aperture.

+Greg Fortune Typically I use 15 or 30 second exposures for fireworks. It sort of depends upon how many bursts I want to  end up in the shot. But let's assume I want multiple bursts as we have in this image: I'd be using 30 seconds and holding a card over the lens between bursts. My actual exposure is pretty much determined by ISO and aperture, typically a low ISO and a high aperture. Something like ISO 400 and f/8 in this example. You could have captured each individual burst here with a 1 second exposure. You'll have to do some early experimentation to see what looks right with you, then just stick with that.

The real trick is trying to get focus right. You won't have anything to autofocus on, and even the phase detect systems generally can't respond to fireworks very well.
 
I think I'm going to try this tomorrow on the mall (well, off it ... I've got 2 spots I need to scout).  I'm thinking about using the 85mm PC-E and seeing how much foreground/reflection I can bring into it.  This I know, is tricky because I won't have a reference point in the air to pre-focus with to get the tilt correct.  The card is an interesting idea, but I'm not sure how I would do that and get good exposure for the monuments as well as the fireworks ... my thought being I'd see what apertures will give me a good monument exposure between 5 and 15 seconds at ISO 100.  I could always slap an ND filter on for even yet more longer exposures, of course.
 
+Vicente Fonseca not using ISO to control exposure is a relic of film days where changing ISO in the middle of a roll was always risking a few frames or ruining one's first exposures on a roll. Doing star trail shots, ISO and aperture are your only controls if you want a specific length of trail and background appearance.
 
I used my D4's video feature to get these fireworks. For a first effort, I thought it turned out pretty well.  You will notice the overexposure as the fireworks accumulated in the sky, but once I corrected it the result seemed nicely filled with detail.  Incidentally, assuming the D800 book comes out before the D4 one, does it book explain the D4 autofocus system in detail since they are supposedly the same?  I would like a deeper understanding of it because there are so many options.   Fireworks
 
+David Dennis based on using my D800E and D3/D3x, I see the controls rearranged but not a lot of other changes that affect me except possibly in LiveView mode. In particular, the choices of focus point selection modes in AF-C look the same and the custom functions are the same as far as I can find right now, at least as far as description. For the most part, they seem to act the same too.
 
+David Dennis oh, I forgot to mention one thing. The speed of tracking in any of the AF-C modes in the D800E are a lot slower than the D3 bodies. This appears to be the same difference that distinguished the D700 from the D3 bodies and the reason I never got one to back up my D3. I would expect the D4 to be faster and more reliable at tracking in the AF-C modes than the D800 and the D3 series though the difference might be barely noticeable to most people. I felt it within seconds of substituting it for my D3 in a shoot.
 
Most of your teaching pictures are very uninspiring. 
 
Very interesting, Herb, thanks for the insights.  At first I really struggled with the autofocus modes but think I'm getting more of a handle on them.  I think most of my problem is that I came from the D300 and wasn't used to focus being more critical in the FX format than it is in DX.  
 
Blend mode to lighten???? I'll try it later.
 
Nice one Tom
Like the color and pattern :-))
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