The Ultimate Guide to Timelapse Photography: Part 2

It’s been a while since part one and I’ve been fairly busy. In this tutorial I am going to go into the more complicated aspects of timelapse photography such as day-to-night transitions (or night to day, they’re more or less the same thing), introducing movement in post processing, dust and spot removal, and avoiding and removing DSLR flicker. If you haven’t read The Ultimate Guide to Timelapse Photography: Part 1, then you should probably go and read that now.

The Gear

This is an intermediate tutorial and this is aimed at people who don’t own all of the fancy pan and tilt heads and timelapse dollys the professionals use. Because of this, I’m going to be using a lot of software. Software solutions are never as good as achieving an effect in camera, but then again software is cheaper and more accessible than video gear. You will need everything I listed in part one and the following:

• Adobe Photoshop
• Adobe After Effects
• VirtualDub and the MSU Deflicker plugin (these are both free)
• An SLR camera. You are getting to the stage where point and shoots and compacts just don’t cut it anymore.

And these are pretty good to have, but not absolutely necessary:

• Adobe Premiere
• An intervalometer capable of bulb and ISO ramping. I use the MagicLantern firmware for Canon EOS cameras. Another alternative is the Little Bramper.
• A lens with manual aperture control. Old lenses without automatic aperture control will help reduce flicker.

Day to Night Transitions

This is seen by many as the holy grail of timelapse photography. Because the light changes from ultra-bright to pitch black it is very difficult to shoot. The technique to defeat the rapidly changing light is called ramping. With the advent of digital camera’s there is two types of ramping: Exposure ramping and ISO ramping. What it entails is a gradual increase or decrease of exposure length or ISO sensitivity. This ensures that the exposure of the image remains the same as the light changes. There are a few different ways to achieve this effect. I’ll be going through 2.

The first of these is to use the ‘Aperture Priority’ setting on your camera. The AP setting will change the ISO and shutter-speed to properly expose the frame using the camera’s inbuilt light meter. All you need to do to is to set your aperture and focus (remember to always use manual focus), connect your intervalometer and start shooting.

Another way is to use a device, such as the little bramper, to control the ramping for you. For this you will need to set the ramping speed manually. I have found that at sunset the exposure changes at about 1 stop per minute BUT bear in mind that the season and your latitude will affect this. Summer sunsets take longer than winter ones and the further you are away from the equator the greater the seasonal variation. Basically if you are doing it manually you will need to go to the place you want to shoot the day before and manually check how quickly the light is changing. To do this set up your shot and set your camera so the light meter is reading dead centre. Then check the exposure (half pressing the shutter) every minute to see how much variation there is. After you have done this you’ll need to sync your interval speed to the exposure change to avoid over or under exposure. If the light is changing by 1 stop per minute, you’ll need to use an interval and exposure change such as 1 frame/m @ +/-1EV, 1 frame/30sec @ +/-0.5EV, or 1 frame/15sec @ +/-0.25EV.

I personally use the Magic Lantern firmware for Canon EOS cameras. It installs a vast swathe of features onto your camera including an intervalometer and bulb and exposure ramping with automatic, sunrise and sunset modes. The sunrise and sunset modes are extremely easy to use and are very good. The best thing about it is that you can set your interval time to whatever you want and don’t have to worry about trying to figure out exposure values. The firmware does it all for you. To use this feature, take the first image of your sequence manually. Make sure you have the aperture, focus and exposure set the way you want the whole timelapse to look. When you’re happy with it press the ‘delete’ button to access the Magic Lantern menu. Scroll left to the ‘shoot’ menu and then scroll down to the Bulb/Focus Ramp option and press the ‘Picture Style’ button. On my EOS 5d mkII it’s the one beneath the menu button. This will open the options for the bulb ramping. For ‘Auto ExpoRamp’ set it to either sunrise or sunset by pressing the ‘Set’ button. Press the ‘Picture Style’ button again to return to the previous menu, scroll up to ‘Intervalometer’ and press the ‘Picture Style’ button to set your desired interval. Then press the ‘Delete’ button to start. The firmware will ask you to select a properly exposed image. Scroll to the image you want to use as the baseline exposure and then press ‘Set’ and your camera will take a few images to get the exposure correct and then it will settle in to the shoot.

Be aware that if you want to see stars at the end of your sunset timelapse you’ll need a fairly long interval. You won’t get decent shots of stars with a ten second exposure. I’ll be going into night timelapses further on in this article so make sure you read that first.

Lens Flare

Some people like lens flare. Personally, I think it’s the devil. If you are shooting sunrise or sunset with the sun in or near the frame and are using an ND filter you will get copious amounts of lens flare. Each filter you put on the end of your lens will reduce image quality and increase flare. My ND filter is a graduated one, which means there’s two pieces of glass that you can rotate to adjust the brightness. It’s awesome until you point it at the sun. When you do that there are abberations and lens flares all over the place. I did say in the last tutorial that longer shutter-speeds are better for timelapse photography, and they are, but sometimes you have to compromise. The beginning of the video below was shot at 1/15sec ISO100 f/22. I would have preferred a shutter-speed of around 1/2-1/3sec but without an ND filter it was impossible. I made up for this by using a relatively fast interval of 1 exposure every 15 seconds. Anything slower than this would appear more choppy. An interval of 1 exposure every 10 seconds would have been smoother. The moral of the story is that you need to be prepared to break the rules when you have to.

Avoiding Flicker

Most flicker in timelapse videos shot on an SLR are caused by slight variations in aperture. Modern lenses have camera controlled aperture. The aperture ring will not stay at what you set it at between shots. Instead it will move to the setting you set it at just before the shot is taken and then move back to its default position afterwards, only to repeat the process all over again. Each time it does this there can be variations in the actual aperture of the lens which results in noticeable changes in brightness. there are a few ways to defeat this.

First is to use an old lens with manual aperture or a fixed aperture lens. If you don’t have one of these the second option is to set the aperture you want, press and hold the ‘Aperture Preview’ button (it’s the one below the lens release button on Canon SLR’s) and then half unscrew your lens. This will disconnect the lens circuitry from the body but will still keep the lens attached to the body. If you do this make sure you re-attach the lens properly before you move your camera again. Thirdly, like I said in Part 1, dragging the shutter will help reduce this somewhat, but won’t entirely eliminate aperture flicker.

The fourth option is getting rid of flicker in post production. There are a few products which can do this including GBDeflicker and LRTimelapse. I use the free option: the MSUDeflicker plugin for VirtualDub. After you install VirtualDub and the plugin import your video, go to Video->Filters and choose the MSUDeflicker plugin. Run it on the default settings if you’ve never used it before and see how the result turns out before you start playing with it.

Shooting Stars

If you’ve already had a go at shooting sunsets then you’re in for a treat. Star-field timelapses are much easier. The aim of capturing stars for timelapse is to let as much light into the camera as possible with a shutterspeed short enough to prevent star trails. If you’ve got nothing in the foreground then the easiest way to do this is to use a really big aperture and focus to infinity. If you are getting tricky and want to have something in the foreground then you’ll need to use a smaller aperture. In this situation you should use a shorter focal length which will allow you to have longer exposures. The formula for avoiding star trails is the rule of 500:

500 / (Focal Length x Camera Sensor Crop Factor) = Maximum Exposure Time in Seconds

For instance, if I was to shoot a star timelapse with my 70-200mm f/2.8 @ 70mm on my full frame EOS 5d mkII the formula would be:

500 / (70 X 1) = 500 / 70 = 7.14 seconds

The same lens and focal length on a 7d, which has a canon APS-C sensor with a 1.6x crop factor, would be:

500 / (70 x 1.6) = 500 / 112 = 4.46 seconds

If you are unsure of what the crop factor of you camera is just type in your camera’s model and ‘crop factor’ into google. It shouldn’t be too hard to find. Just because I’m nice here are some common crop factors:

Removing Dust

Dust is bad. Before you shoot clean your lens, clean your filter and clean your sensor. But even when you do all of this dust can blow all over your lens during the process of shooting a timelapse. I use After Effects to remove dust spots on my timleapses. The one I shot for this tutorial had over a hundred dust spots, which is absolutely ridiculous. The technique I use is from Magic Timelapses. If you don’t have After effects you can do it in Photoshop. The tutorial for that is here.

Ridiculous amounts of dust

To get rid of those annoying dust spots you use the ‘Dust and Scratches’ filter in AE. Because it looks rubbish when you apply it to the whole image you need to duplicate the layer in AE. Select the top layer and use the ellipse tool to circle all of the dust spots. Underneath the layer you’ll see masks start to appear. When you have finished highlighting all of the dust spots, select all of the masks and change the value of ‘Mask Feather’ on one of them to something like 5-10. With all of them selected, whatever you do to one will be applied to all of them. Select the top layer and apply the ‘Dust and Scratches’ filter (Effects->Noise and Grain->Dust and Scratches). Keep the threshold at zero and play with the radius value until the dust is more or less gone.

Removing dust in After Effects

And the dust is gone

Panning

One thing I have discovered about videography is that movement is key. Timelapse is no different, if there is no movement in your scene it will become boring after about three seconds. One way to introduce movement into your shot is panning. Panning involves the gradual and continuous movement of the camera and, for timelapses, usually requires an expensive timelapse dolly to achieve. If, however, you can’t afford a dolly you can achieve a similar effect in After Effects.

Before you fire up after effects you need to think about the aspect ratio you’ll be trying to shoot. When you crop your images you need to consider one axis only. For instance, if you are creating a vertical pan you will need to crop the width to 1920px (for 1080p resolution) and have the height set to anything greater than 1080px. For horizontal pans you crop to the height. When you’re shooting you’ll need to think about which parts of the frame you are actually going to use. For instance, the shot of the lavender in the video below was cropped to an aspect ratio of approximately 32:9 meaning that almost half of the frame in camera was discarded.

I crop my frames in Lightroom and when I export them I set either the height or the width parameter only, not both. Remember your desired output resolution here. I usually aim for 1080p which is 1920x1080px. Because we are using After effects to create the pan it makes sense to import the image sequence directly into After Effects. Because of this make sure you export your images from Lightroom as Tiff files.

Import your Tiff files as an image sequence in After Effects (File->Import->Multiple Files, select first tiff in the sequence and ensure ‘TIFF Sequence’ is checked at the bottom of the import screen) and apply any dust removal or colour correction. If you still have multiple layers you’ll need to link the layers together. In After Effects this is called ‘Parenting’. Set the parent layer of all layers above the bottom one to the bottom one using the menu next to the timeline. To create the pan I use the ‘Drift Over Time’ animation. You’ll find it on the ‘Effects & Animations’ panel on the right hand side of your screen. The path to it is Animation Presets->Behaviours->Drift Over Time. Drag that onto the bottom layer of your composition. Set the direction and speed of the pan in the panel of the left and use the ‘Ram Preview’ feature to fine tune it. Now you can render your composition by selecting Composition->Add To Render Queue which will add it to the render panel down the bottom. Select your parameters in the render panel and then click ‘Render’.

Drift Over Time

And after all that you should be able to create something like this:

http://www.youtube.com/watch?v=u-qzNtf3mio