Tag Archives: compositing

Sequenced Shots (How To)

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How on earth did I end up with this:

Annular Eclipse Sequence [C_040079+fives]

What I started with was lots of shots that looked liked these first three images – i.e not much of anything.

As I went along I ended up combining the “specks” into the image at the lower left. I combined the sequence with a shot taken just after sunset (middle bottom) and the result is as shown in the lower right.

We will soon provide the explanation of how to create the result. First we would like to give some clues about how the shot was planned – because, as it turns out, planning is an important part of all sequences like this one!

Avoidable Technical Content

The May 20, Annular Solar eclipse was well documented. Particularly handy is Nasa’s map based application. Choose a spot on earth by clicking on the map and some useful data pops up:

See those highlighted numbers… they tell you that when the eclipse starts it will be 31.5 degrees high in the sky, and when it ends it will be 5 degrees high – about 27 degrees top to bottom.  Allowing another 5 degrees above and say 10 below we need an image that spans 42 degrees in one direction.  Looking at the Azi numbers  The eclipse begins at 270 degrees (due west) and ends at 292.2 degrees (WNW).  So to take that all in and allow a little breathing room we need about 30 degrees.   Thus we know our field of view needs to be somewhere around 42 degrees vertically and 30 degrees horizontally. Already it sounds like we would prefer portrait mode to keep the sun/moon as large as possible. Using one of the many online tools, like the Angular Field of View Calculator by Tawbaware. Canon people might prefer the “easy to click, but perhaps not so easy to understand Canon equipment specific calculator.”

On a full frame camera, the 50 mm lens comes out to 39 x 27 degrees. which would just fit the whole sequence.  I decided to use my 70mm lens – because I already had a solar filter for it. My plan was to wait until I could catch the sun in the upper left of the frame and the foreground I wanted at the bottom. When the sun arrived, I slapped on the solar filter and started automatic 30 second intervals between exposures.

Or Just Go with Luck

Perhaps my first attempt was not so well planned.

Mamma Glows, Baby Shines

I was too interested in keeping Mt Tamalpais in the picture and ALMOST didn’t get the whole moonset. I know better now! Over three years ago I described how I created the image.  The technique is an extension of my previously described Easy HDR method.

To Be Continued…

In Part 2 of this article, we will show you a few helpful little addenda to make the process easier to manage. We will reveal a Photoshop-only method to approach the problem, AND for good measure a nifty tool to make it easy as pie.

Meanwhile if you are intrigued by the moon, you might want to join us from WHEREVER you are on one of our fun, informative, and oh so reasonably priced Moonatic Webinars.  Or maybe the next Photo Manipulation webinar is just your size.

Action! Creating a Timelapse Animation (Part 1 of 2)

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One of the nice little benefits of using the stacking technique to create star trails is  that you can take those many frames and animate them.  My first foray into animation looked like this:

“Star Races” was created using the stacking features of StarTrails.exe (Windows program) and composed into a movie using the “Animation Feature” of that same tool. The vertical format works well with the portrait mode images. This video contains no music or titling as those are not supported by StarTrails.exe.  I will cover the technique to create this in Part 2.

A more elaborate effort with music, stacking and credits is this one created from 8 hours worth of images using the tool Picasa which is free and available for windows and mac:

Not all time-lapses need be created from night images, however. An early example of a daylight animation chronicles my son scaling a rock in Zion. I later did a similar animation using a tripod. The method used to create the animation will depend on the number of frames available and the intent. Let me start at the beginning however.

Shooting Time Lapses

A time lapse requires “frames” – individual pictures used to create the end result.  Usually pictures used to create a time-lapse will be at relatively low resolution (1920 x 1080 or smaller) so shooting them in large format, RAW means extra work will be required to assemble them.  On the other hand, my time-lapse are byproducts of my star trail shots and I always shoot those in maximum sized RAW mode.  An important consideration is the frame rate – that is the number of images shown per second. A movie typically consists of 30 frames per second, so to shoot 5 minutes of video one needs 30 frames per second for 60 seconds x 5 minutes. 30 x 60 x 5 = 9,000 images. Yes, that is a LOT!  However often a frame rate of 10-per-second is acceptable, so only 3,000 images are needed – still quite a lot.  Perhaps we shall start a little less ambitiously and collect 300 frames – enough for a 30 second animation at 10 frames per second. Assuming we are shooting these at night with 2 minutes each exposure it will take 600 minutes (a mere ten hours!). If that still seems like too much work, we can settle on shooting 1 minute exposures and have the shooting done in a 5 hours.  Clearly patience is required. Unfortunately when shooting the night sky it is unrealistic to expect exposures to take less than about 10 seconds even at high ISO.

The software used to assemble the video may also impose limitations. For example in Picasa’s time-lapse mode the minimum frame rate is 6 per second and the maximum is 24. In “Dissolve” or “Cut” mode, the minimum is 1 per second.  The Zion climbing shot is done in Dissolve mode.

Animation Software

Lots of tools exist for this. I’ve already mentioned Startrails.exe and Picasa (Mac or PC), but there is also Windows Live Movie Maker. Each of these tools is free!  Windows Live Movie Maker is the most versatile free tool I have tried with titling and transition options.

Non-free tools for the PC include Adobe Photoshop, Adobe Lightroom, Adobe Premiere. For the Mac there are iLife (iMovie), Final Cut Pro, and many others.

Music, Copyrights and Credits

While a simple time-lapse may be interesting adding music makes it more so. The free tools support music in some (small) fashion but sometimes just barely. Picasa for example will let you select an MP3 song. Unfortunately when creating a time-lapse it will not let you select where to start in the song and does not fade in or fade out – and only one track is allowed.  If you really feel ambitious you can use iTunes to create a segment of a song to include.   Search Google for “creating ringtones in iTunes” (which will help you figure out how to create a snippet), and “export iTunes as mp3”. Creating a snippet using iTunes is not particularly easy, fast or convenient, but it is free – and as a bonus you will discover that you have been wasting money paying for ringtones!

Copyrights and credits can be done in several ways. Live Movie Maker is actually pretty easy to use and allows different text effects. In Picasa you can use captioning (which is only modestly useful for a time-lapse) or text overlays using the Text Tool. The Text Tool is the most versatile but unfortunately in Picasa you can not say “repeat this frame for 5 seconds”, you have to make 5 seconds worth of frames from one image, or keep adding the one image into the movie. If your frame rate is 20 frames per second, you will have to make, gulp, 100 frames for that 5 seconds of copyright or credit!

Creating the Animation

In the next installments, we will show how to use Picasa from beginning to create a time-lapse with music, titles, and credits.

The first 180 images used in the time-lapse are these:

180 of the 675 frames used for the animation

While the title and credit frames looked like this

Title and Credit Frames

Tip: Avoiding Lens Flare

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Photo 1: Flare shows as discolored areas below and to the right of the sun in this image. This image was taken during the same time as my Photon Worshippers image which won Astronomy Photographer of the Year, 2010. The unnatural appearance is a result of processing several images using high-dynamic-range (HDR) software. HDR processing did not eliminate the flare which detracts from the beam of light shining through the portal.

A common problem facing photographers – night or otherwise – is the lens flare that may occur when a bright light source is in the frame or just off axis.  Flare is evident in several locations in Photo 1 – notably at the saddle of the rock and in the water at the bottom center of the image.  Photo 1 was processed using high dynamic range techniques but those techniques did not eliminate the flare. Sometimes flare provides an enhancing effect, and sometimes not.  Below are two tips you can use to remove unwanted flare from your image. These tips work best when using a tripod to capture your images. And tips that work in the daytime also work at night.

Masking and Combining

Not many people realize that when flare is present, there is also often a reduction in contrast called “veiling glare”. This effect is sometimes more pronounced when using a filter. Our first recommendation is to always use a properly sized hood to block as much out-of-frame light as possible. When the bright light is in the frame, or is not fixable using a hood or manual shielding a powerful technique is to combine two shots as illustrated below.  The large upper shot is the result of combing the two lower shots.

Removing Flare by Masking off the Sun

Illustration 1: Removing flare and increasing contrast by masking off bright light sources

Obviously this technique works best when using a sturdy tripod – something we always recommend.

The method for combining two shots depends, of course, on which tool you use.  Books I recommend that describes how to do this sort of manipulation are these by my friend and fellow instructor Harold Davis:
The Photoshop Darkroom 2: Creative Digital Transformations
The Photoshop Darkroom: Creative Digital Post-Processing

My final, awarding winning “Photon Worshippers” image was processed using the “Hand HDR” technique described in “The Photoshop Darkroom“.  It took quite a bit of effort to remove the flare from the image – because I had not yet discovered the technique described here!

Blocking Errant Light

A similar strategy works especially well when taking long exposures at night – and it requires only one exposure. The bright rotating beacon from the lighthouse in Illustration 2 created problems for a 20 second exposure.  The flare from this intermittent bright light was managed by using a hat as a shield just before the bright beam swept across the camera.

Illustration 2: Using a shield to block intermittent bright light

This blocking strategy can also work when a car, hiker, bicyclist or other light bearing object sweeps light in the direction of your lens.  Unless the palm of your hand is coated in matte black soot, you won’t want to use your hand for this purpose. Be careful not to bump your lens or tripod when blocking the light and be sure to use a dark, non-reflective object to block the light because even if you have coated your hand in soot you probably won’t want to get that dirty stuff anywhere near your camera.

Learn more tips like this one at a Star Circle Academy Workshop where you’ll not only learn how to create compelling star trail images in fabulous places, but we’ll even provide you with a wet-nap to get that soot off your hands 😉