Tag Archives: focus

Skies Ablaze – Capturing Fireworks

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Pod People [C_033010]

Photo 1: Abstract Sausalito fireworks (aka Pod People)

Several times a year Americans (and others around the world) find an excuse to gratuitously burn large amounts of black powder in spectacular displays that serve no real purpose except to create awe and wonder. For that reason alone, I love fireworks.

Fireworks are an interesting subject for Night Photography and require a little patience and experimentation to do well. And I have found some new approaches to photographing fireworks that make them even more interesting – as shown in Photo 1, above. Yes… that is a firework burst!  For information on how I achieved that effect, see below.

Challenges with Fireworks

Fireworks come with their own set of issues. From the ephemeral nature of the light to the selection of a site to photograph them from.  I generally favor more distant locations where I am able to switch between telephoto and wide angle lenses to alter the composition of the shot.  At greater distances the flashes of the fireworks are also a little less challenging photographically.

Brief Intense Light

Firework bursts are brief lasting seconds or less, but surprisingly they are very bright. Because they are so brief catching them at just the right moment may at first seem daunting. As with all things night photography the camera is quite inadequate at metering or adjusting for fireworks in a way that will capture the drama and grace. So the first tip:

Tip 1: Stay in MANUAL mode and do not let the camera try to adjust anything.

I generally prefer settings that are approximately like this:  200 ISO, f/9, 10 seconds.  But may change those dramatically based on the outcome of a shot or two, and how much background I’m trying to grab.  For example, I will often choose shorter exposures at higher ISOs, and sometimes I use BULB mode.  More on that in a moment.

Location, Location, Location

As in real estate, location is everything. Fireworks, in my opinion look better against a city skyline, reflected in water, or next to the moon or a snowy mountain peak. But creating an exposure to include those background elements is tricky, sometimes very tricky.

Nearly every event in which fireworks are employed is massively crowded (think 4th of July) so finding a clear view and a safe hassle free space to set up a tripod takes a little creativity and patience. Fortunately fireworks can be viewed from near or far – and far is often a bit better.

Photo 2: Fireworks and the San Francisco Skyline

Weather may also be problematic – as in the San Francisco area where fog in the summer evenings and mornings is normal. Four years of shooting produced only one year with moderate haze (as in Photo 2). Two years were complete shutouts.  Photo 2 could be improved with a brighter background – either by taking a longer exposure at the time or by combining with an exposure taken earlier or later in the evening.

The minions in the Night Photography group were clamoring to shoot fireworks, but thrice burned equals twice shy despite a fantastic location found years earlier.

Tip 2: A good location is always the better choice. Location, location, location!

Composition

Wide shot or tight shot?

Photo 3: Tight coverage of a burst

Photo 4: Wide angle with pond and reflection

Straight shot or creative shot:

Photo 5: Changing focus during exposure

Fortunately there is no rule that says you can not try a number of different approaches in the same event – provided the event lasts long enough.  However it is best to start with trying to get a pleasing result that is conventional in nature that is, more like Photo 4, above.

Timing

As in comedy, timing is important.  Start the exposure too soon and you’ll catch the bright burst of the firework which may very well overwhelm the camera and produce a “white blob”. There are three approaches to the timing problem, and sometimes I use all three in the same night:

  1. Set the camera up with an intervalometer/locked remote shutter and just let it run.
  2. Manually release the shutter using a fixed exposure length as soon as you see a burst.
  3. Manually control the shutter in bulb mode.

The main reason to use a fixed exposure length is if you intend to stack or animate your photos – keeping the background exposures the same produces a more pleasing, flicker free result. However if your only goal is to “get the boom”, option 3 is probably the best.  I recommend shooting after the initial “boom” because what makes the firework appealing is the light spreading and then falling over time.  How long to expose depends on a lot of things, of course, including how bright the background is and how many fireworks are blowing up at a time.  The Finale is usually a good time to take your eye off the camera and enjoy the show because finale’s usually end up a washed out mess.

Tip 3: Start the exposure immediately AFTER the boom.

Creative License

So how did I get the strange effects in Photo 1 and Photo 5?  I adjusted the focus while exposing.  I have also played with the zoom while exposing.  In Photo 1 the shot started focused and I defocussed it.  In shot 5 it was the other way around – it started out of focus and finished less out of focus.

Once you start playing with the focus, do not expect to have sharp images which is why I recommend you get the conventional exposure first before you get all creative.

 

Trouble with Long Exposures – Part 1 of 2.

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I administer a group on Flickr called “Star Trails” and moderate a group called “Best of Star Trails“. The good news is there is a constant source of new exciting photography there… and a fair number of beginners facing some common problems. Some of the problems are due to limitations in the camera, and some are due to the selection of exposure time, ISO, f-stop or focus. Some are due to cockpit errors of the kind I described in my August 13th article: Many Paths to Failure regarding unattended shooting with an intervalometer. This list is in addition to those problems and in a way is a bit more fundamental.

Common problems are:

  1. Poor Focus
  2. Dim Stars (low contrast)
  3. Strange Colors
  4. Purple or Pink Glow
  5. Gaps in Star Trails – see part 2.
  6. Lots of Noise (Colored Speckles) – see part 2.

Let’s tackle those one at a time.

Focus is Poor

Poor focus is a topic unto itself which I covered in My Camera Can Not Focus in the Dark – And Neither Can I! But there are a few other causes besides having an incorrect focus. Additional problems that may create noticeable lack of sharpness:

  • An unsteady tripod (often noticeable when there is wind). And it may not just be the tripod. Check the quick mount plate and the tension on the knobs.
  • Condensation (that is dew) on the lens. Use a lens hood (helps), and if really bad a lens heater.

Stars Are Not Very Bright

Often the lack of stars is due to an unnecessarily small aperture. Selecting a smaller aperture can help with your image, too. Here are some examples. First is an example from Miguel Leiva:

Photo 1: f/18, ISO 100 for 30 minutes.

???? Trails of Moon, Venus & Jupiter over the Nepean River 30/11/08

Photo 2:  f/20 ISO 400.

In Photo 1 a small aperture allows greater depth of field so that focus is sharp from the foreground to infinity but that small aperture also diminishes the contrast in the stars. Taken to an extreme a high f-stop (tiny aperture) with stars can produce an effect like that in Photo 2 by Vincent Miu which was a runner up in the 2009 Astronomy Photographer of the Year contest.  The very small aperture, f/20, eliminates all but the brightest elements from the night sky.

While a tiny aperture reduces the number of stars captured, a large aperture (small f-stop number) and/or a high ISO results in many more visible stars especially when the sky is dark. Compare these shots:

Cone Heads STILL in Awe [22012-2362]

Photo 3: f/3.5 at ISO 640: A lot of stars make for a pleasantly dizzying image.

(son of) Bristlecone Pine Star Circle

Photo 4:  f/4 ISO 100

Photo 3 was shot at f/3.5 ISO 640, while Photo 4 was f/4, ISO 100. Both  include about the the same star field but  many more stars are present in the higher ISO shot.  Even if you are not trying to reduce the number of stars in the field, you might be forced to use a smaller aperture to get more depth of field.  Another common problem that causes reduction in contrast is sky glow. When the sky itself begins to lighten you can be sure that the stars will not contrast well.  The best way to control this is to take shorter exposures and later at night – or on a clearer night (cold winter nights produce the clearest skies). The moon is also a huge source of glow. Treat the glowing moon just as you do artificial light glow – reduce your exposure length (and ISO) to take pictures when the moon is strong. But do not give up just because you can barely make out stars in your night sky – the camera can see them better than you can!  Photo 6 is a perfect example. The city glow made it impossible to see more than 8 or 9 stars toward the north and yet the star trails are quite present.

Colors are Strange

Many people are surprised to see that the stars in their photos are different colors: red, orange, yellow, blue and white. Those are the natural colors of the stars. People are also surprised to see a blue sky however even modest amounts of moonlight or a very long enough exposure will result in blue sky! Unfortunately sometimes the stars or the sky are unnaturally colored. Usually the culprit is one or more of these factors:

  1. Incorrect white balance setting (I recommend “Daylight”)
  2. The presence of artificial light.
Pleasanton Circular File [5_018700-20]

Photo 5: White balance problem due to different types of light. In this image I compromised to keep the colors on the land as natural as possible.

Getting the white balance right is not hard except when there is lot of artificial light – streetlights, city glow, etc. Unfortunately there are many different types of lights each with their own color characteristics. The popular low pressure sodium vapor lights are nearly monochromatic yellow-brown in color. There is really no way to get a naturally colored look when sodium lights predominate the scene. Florescent, tungsten, LED, and other light types all differ in their color profiles and when several different sources are in play for a scene it gets harder to keep a natural looking scene.

Sometimes when handed lemons you can make lemonade as in Photo 6. I could not correct for the predominate sodium vapor lights so instead of fighting I adjusted the color temperature to make the foreground elements look as natural as I could and did not worry that the stars became white – most people think of them as white anyway. It certainly helps that the image also includes a portion of twilight illumination to help keep the scene realistic looking.

A City and A Mountain. Part A [5_024371-434g]

Photo 6: When corrected for the sodium vapor lights the mountain looks almost natural, but the stars have lost their color.

And there is yet one more way to solve the color problem; but you will have to do some editing. To fix different color lights you can color balance each element separately and then combine the elements into one image. For example using “Daylight” white balance for the star trails and “Tungsten” for the street scene may produce a natural and pleasing looking photograph. Photo 6, above was manipulated in a similar way. Once it became completely dark the glow from the city lights caused flaring and ghosting. The solution was to choose one properly exposed frame from twilight and layer that on top. Layering like this is easier if you have an overexposed daylight shot that you can use as a mask. More on that in the Night Photography Workshop

There is Pink or Purple at the Edges

Some cameras, particularly older models may suffer from “amp noise”. The glow or noise is usually visible at the corners or edges of the photograph and usually only with longish exposures (over 8 minutes). Here is an example from Ethan Doerr of what “amp noise” may look like.

star trails

Photo 7: Amp noise is prominent in this photo taken on a Nikon D80 with a 572 minute exposure at 100 ISO. Nikon: D80, D90, D40, D200, D3000, and possibly other cameras may exhibit similar anomalies. Photo by Ethan Doerr – used with permission

If your camera is subject to amp glow there are some tactics you can try. The simplest is to keep your exposures short and stack them. Or perhaps allow the camera to cool down from time to time. Or only shoot in Antarctica ;-).

For more Trouble with Long Exposures see Part 2.

My Camera Can Not Focus in the Dark – And Neither Can I!

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Original Publish Date: Sep 20, 2010
Updated: November 15, 2017

A common and vexing question is “how do I focus when it is too dark for the camera to auto-focus, and too dark to manually focus?”

There are five strategies that I commonly employ, but before I describe those strategies, it is important to understand a little bit about what focus is and is not. There is no such thing as perfect focus. How to achieve focus will depend on several factors especially the focal length of the lens, the lens speed, the clarity of your viewfinder, the accuracy of the markings on the lens (if any), whether your camera has live view, and whether there is any bright object that can be used to focus.

It might sound silly, but you should start by thinking about what you WANT to be in focus. Usually for a star shots everything should be in focus from the foreground to the stars in the sky.  The stars do NOT have to be perfectly focused, however – more on that in a moment.

Why does focal length matter?

More than anything else the focal length of the lens dictates the depth of field. A long focal length (200 mm for example) results in less depth of field while a short focal length allows a greater depth of field. The depth of field matters quite a lot if you are trying to get a foreground object against a background of stars. The longer the focal length the farther away your foreground must be to keep both the foreground and the sky in focus. The ideal point to work with is your “hyperfocal distance”. Keep your foreground at or beyond your hyperfocal distance and all will appear as sharp as the lens and conditions will allow.

Hyperfocal Distance

Hyperfocal distance decreases as you stop down and increases as you open up the aperture. Shorter focal length lenses have shorter hyperfocal distances. Indeed a 17mm lens at f/5.6 has a hyperfocal distance of about 15 feet (2.8 meters) while a 200 mm lens at f/5.6 has a hyperfocal distance of 1,250 feet (381 meters). That is quite a difference! These numbers assume you are working with a 1.6 crop factor. When using a full-frame (35mm) sensor the distances drop to  1.72 and 238 meters respectively.

But… How DO I Focus?

Ok, with those details out of the way the question remains: how do I get good focus when it is too dark to see to focus.  Here are the methods I recommend. Start by turning OFF auto focus. I am embarrassed to say how many times I have carefully focused only to discover that I did not turn off autofocus!

  1. Do not wait until dark to focus. Focus on your foreground when there is still enough twilight to see clearly. Put gaffers tape, or a lens band across the rings so that focus does not change accidentally.
  2. Use “Live View” and zoom-in to sharpen focus if your camera allows it and there is sufficient light.
  3. If not enough light, find a bright light source in the area and focus on that. The moon, is a good choice (though a closer focal point may work a little better). Try  a nearby streetlamp, sign or other bright object.
  4. Bring your own BRIGHT light source and use it to focus on something at or beyond your hyperfocal distance.
  5. Take high ISO images to confirm your focus and then make minor tweaks to the focus. The High ISO image will be grainy but it will also help you verify what is within the frame of your photo. Tweak the focus and shoot again.

Before you invest a tremendous amount of energy getting the sky in focus consider that the stars are point sources of light anyway. Perfect focus at infinity will improve the contrast of the stars against the night sky, but sharp foreground against a slightly out of focus sky is preferable to a sharp sky and out of focus foreground… at least in my opinion.

One last comment about focusing at night.  You will find more success focusing most manual lens and high-end lenses than autofocus lenses – especially the less expensive ones. Why? Autofocus lenses are cheaper and easier to make if the lens does not stop at the infinity setting and if focus can be achieved with less movement of the lens elements. Autofocus lenses, after all are designed to focus quickly. A manual (or higher end) lens might allow a half or full turn for the focus adjustment range while an autofocus lens may have a mere 1/16th of a turn to tweak with. Curious what other characteristics make for a good night photography lens? We have an article on that.

Topics such as this are covered hands on and in more detail with our students in our Star Circle Academy Workshops.

Are there any other focusing tips, techniques or apparatus?

Why of course!  See here, and here.