Twinkling Sky

Rather than a still image, I chose to use a composite of images called a time lapse video as my Pic of the Week this time as there has been quite a bit of interest around astro photography and the settings used.

This image is from the pathway to the east wing of the suites at Little Bush Camp. The series of images was captured over 45 minutes while we had dinner and when I knew there would be no traffic to and from the suites. I chose a very clear evening and there was no moon until much earlier in the morning, so no light to interfere. The lanterns along the path added some interest to the foreground and brought out the detail in the trees.

Equipment used

Camera – Canon 7Dmkii

Lens and Focal length – Tokina 11-20mm f2.8 @ 11mm

Settings used to capture this image

ISO 2000 – High ISO at night so as to gain as much light sensitivity. I find that ISO 200 does not introduce too much grain in the form of noise and you get a decent amount of stars in your image. Higher than this will give you more stars but also much more noise.

Aperture f2.8 – The lowest possible aperture so as to capture as much light as possible.

Shutter 20 sec – used a very slow shutter speed so as to capture as much light as possible seeing as we are working with light that is lightyears away but at the same time not too slow so as to introduce too much light from the lanterns close by or star trails in the stars themselves due to the rotation of the earth.

Intervalometer 25 sec – I set the intervalometer settings to 25 seconds so as to accomodate the 20 second shutter. This also gave the camera 5 seconds to cool down after such a long exposure. This went on for just over 45 minutes (Intervalometer is basically a self timer that automatically relaeses the shutter at a predetermined time).

Editing used on this image

Quite a bit of editing goes into an astro image so as to pop the colours as well as detail of the stars. I introduced quite a bit of light in the highlight regions and dropped the shadows to make the stars stand out more.

On the basic side of editing this is what I did: raised exposure and contrast as well as clarity quite a bit. Dropped highlights, whites and blacks a bit and then also dropped shadows substantially. On the tone curve portion, I raised the highlights very high as well as shadows by a bit; lights and darks were raised a small amount. Sharpening was added as well and I made heavy use of the masking feature in Lightroom to localise the detail in the sky to just the stars themselves and soften the sky inbetween. This coupled with raising the luminance slider produces a beautiful soft sky with pin sharp stars. An amazing feature in Lightroom is the dehaze slider which I raised in this image, this removes any heat haze, light haze or pollution haze in an image and generally just makes a sky-based image sharper.

After this I made use of an awesome tool called “virtualdub” to composite all the still images into one video.