On our recent trip to the Grampians, Neil and I did some late night star trail photography at Lake Fyans.
A few people have asked me how I did it, so I thought I’d share my information with you all.
With digital cameras and remote shutter releases, it’s fairly straightforward to take star trail photos. I recommend taking multiple shorter exposures and merging them because digital sensors build up heat over long exposures, causing red/purple casts to appear at the edges of the sensor and ruining your shot. Using shorter exposures is a way around this.
For my photos above, the details are below.
Camera: Canon 40D
Lens: EF-S 10-22mm
Focal Length: 10mm
Shutter Speed: 30 seconds x 114 shots & 111 shots
WB: Auto White Balance
Remote shutter release cable
Drive mode: Continuous shooting (burst)
Focus point on the tree (using a torch to illuminate the tree to get the focus point)
Step 1: (RAW file adjustments to all 114 shots)
Exposure adjustment: +0.9 (to get the exposure level I was after)
Exported the 114 shots as JPEG
Step 2: (Merging photos)
There are a couple of methods of doing the photo merging.
Achim Schaller has written a wonderful Startrails Application to merge all exposures into one JPEG.
It also can create a time-lapse movie ! (see mine below)
Another method is to use Photoshop and combine all layers using “lighten” merging. A handy and time saving method is to use Chris Schur’s Photoshop action.
Step 3: (JPEG Adjustment)
Noise Reduction (100% colour & luminance)
Depending on what effect you are after, compose your shot accordingly.
For my photo above, I composed the shot using the south celestial pole (see image below sourced from wikipedia) which give the circular effect.
The north and south celestial poles are the two imaginary points in the sky where the Earth’s axis of rotation intersects the imaginary rotating sphere of stars called the celestial sphere. The poles appear directly overhead to an observer at the North and South Pole’s.
For those living in the southern hemisphere, there are a few methods to find the south celestial pole.
Southern Cross Method
The south celestial pole can be located from the Southern Cross and its two pointer stars.
Looking up at the Southern Cross, draw an imaginary line from the two stars at the extreme ends of the long axis of the cross and follow this line through the sky. You can either go four and a half times the distance of the long axis on the Southern Cross in the direction the narrow end of the cross points, or join the two pointer stars with a line, divide this line in half, then at right angles draw another imaginary line through the sky until it meets the line from the Southern Cross. At this crossing point is the south celestial pole.
Magellanic Clouds Method
Using the Magellanic Clouds clouds in the southern sky, make an equilateral triangle, the third point of which is the south celestial pole.
Using a compass, locate true south and point up to an angle equivalent to your latitude.
For example, if you were in Melbourne CBD (-37.814056,144.96168), then using your compass facing true south and looking up at an angle of 37.8° will give you the south celestial pole.
Below is a compiled video of all of my 114 exposures from Lake Fyans in the Grampians, showing the celestial movement around the south celestial pole, located at the end of the tree’s branch. (Thanks to “Achim Schaller” for this wonderful application).
You’ll notice too that the light seems to fade on the lake and the tree goes in shadow. This was because the moon was behind us and was fading to the horizon over the hour of exposure. Also the bright light appearing across the lake at the end of the sequence was a car.
I did some White Balance (WB) testing with my Canon 40D to confirm and answer a question I had;
Does it matter what WB I shoot in with RAW ?
Below I provide some information on WB and step through my test results.
Information About White Balance
As we all know, photography is about light. Correct white balancing is about getting the white light right.
Our eyes are good at judging what is white under different light sources, so a white object looks white no matter what type of light we are in. However, digital cameras have difficulty with Auto White Balance (AWB). We therefore need to tell digital cameras how to interpret the colour of light so it produces the most natural looking colours in a photo. By selecting a certain WB, the software in the camera adjusts the colour temperature to make those white areas look white in the photo.
An incorrect WB can create incorrect color casts, which are unrealistic and unnatural. Understanding digital WB can help you avoid incorrect color casts created by your digital camera’s auto white balancing.
A digital camera’s AWB may obtain the correct white balance, but not all the time. So it’s important to recognise the light you are in and adjust the WB accordingly.
Proper camera WB needs to take into account the color temperature of a light source, which refers to the relative warmth or coolness of white light. Examples of WB are tungsten (lighting from warm incandescent globes), Daylight (light from a sunny day outdoors), etc.
Cameras allow you to select the WB, giving you the freedom to get close to the correct colour temperature of the light you are in. This process will remove the unrealistic color casts so objects which appear white in real life will be white in your photo. Some cameras allow you to manually select the exact colour temperature by photographing a white object and recording that data to use as a custom white balance.
In some situations you may need this WB to be very accurate. For example, fashion and advertising photography where a designer will want the colours accurately recorded. And portrait and wedding photography where accurate skin tones are necessary. In these cases the use of a target and custom white balance may be essential because the WB selections available in camera are only approximations.
The table below is taken from the Canon user manual, showing the approximate colour temperatures for certain lighting.
|White Balance Mode||Colour Temperature
(Approx. K (Kelvin))
|Cloudy, Twilight, Sunset||6000|
|White fluorescent light||4000|
The chart below shows the path that a black body color will take as the black body temperature changes. Lines crossing the locus indicate lines of constant correlated color temperature. (for a technical explanation, see the source from wikipedia).
In layman’s terms, the chart shows the colour cast of a certain light temperature.
Eg; Tugnsten light (approx 3200K) is a warm light and has a yellow cast, the chart shows it will follow a path having a yellow colour.
Now for Some Test Results
Getting back to the question,
Does it matter what WB I shoot in with RAW ?
The first 3 test photos shown below are taken with the same settings, on a cloudy evening at sunset, but for each photo, a different WB was used. You can see the obvious difference in colour.
Test Photos – Different WB, Displayed “As Shot”
I modified the temperature of the RAW images during post processing to check if shooting in a certain WB had any effect. The 2nd set of RAW images below, are the same photos shown above, but set to “Cloudy” WB set during post processing.
|Shot @ Cloudy, WB set to Cloudy||Shot @ Tungsten, WB set to Cloudy||Shot @ Fluorescent, WB set to Cloudy|
You can see that the colour temperature is identical in all 3 RAW images.
Benefits of Shooting in RAW
Results show that the best white balance solution is to shoot using RAW.
This allows you to set the WB after the photo has been taken, not having to worry about setting the WB on shoot.
However, some people like to shoot in JPEG, (i.e if they are restricted with space, or want to easily transfer photos or don’t have the time to post process), and some people don’t have a choice to shoot in RAW if their digital camera does not support it. In these situations, WB selection is essential for good, realistic results.
It may also be essential to get the WB right on shoot as mentioned above (e.g. fashion and advertising photography and portrait and wedding photography) where the colours and skin tones need to be accurately recorded.
So, if you can, always shoot in RAW to take advantage of the benefits and it is probably also good practice (depending on your situation) to set the WB correctly and get it right first.
While at Clifton Spring jetty last night, I decided to do some aperture testing with the Canon EF-S 10-22mm on Canon 40D and found some interesting results.
When shooting a normal landscape image it is normal to attempt to keep as much of the image in focus as possible, so I was usually setting my aperture to f/22 at 10mm and focusing at the hyperfocal point (1/3 of the way into the frame) to get the maximum depth of field, but I may rethink after seeing my test results.
The image below shows the 2 RAW photos, identically composed shots in Aperture priority mode (Av), with ISO (100), cloudy white balance, tripod, remote shutter release and focused on the same point on the post.
Left image is at f/22, and right image is at f/8.
The difference in sharpness is very noticeable.
In this situation, the dof was not overly important as I was looking out over the bay and didn’t necessarily need it to be large.
The image below is further into the frame. You can still see the sharpness difference.
Other things that came to mind when checking the results
- could the slight breeze for the 30 second exposure at f/22 have caused some movement and had an effect the sharpness ~ possible, but it was not really windy and the camera was mounted on the solid Manfrotto 055XProB
- could the soft sand have moved slightly over the 30 second exposure to cause movement ~ possible too.
Well, I’ll be definitely thinking a lot more about my aperture setting for my landscape photos in the future
The best sharpness range I found on this lens is between f/8 to f/13.
Depending on the situation, consider whether it is necessary to have your aperture stopped all the way down. In some situations this is required to achieve the desired shutter speed, but it’s good to know your lenses limitations, so I would recommend doing similar tests with your lenses to know them and their sharpest points.
Hope this information has been helpful !
Just wanted to share some knowledge and the ‘how to’ for those who didn’t realise how you can recover your deleted images off your memory cards.
On the weekend I stupidly, but accidentally deleted my early morning long exposure photos off my 8GB CF card, including my ‘Point Lonsdale Pier at Dawn’, but here it is recovered:
Best practice I’ve found (learning from mistakes) is summed up here:
1. Format your memory card before any shoot, that way you’ll start from a clean/empty card and you won’t have to worry about going back and deleting old images (and then delete the wrong ones like I did)
2. If you do accidently delete your shots, don’t stress, remove your memory card from your camera straight away – this is the most important part – don’t take any more shots on that memory card – you could overwrite your deleted photos.
3. There are many programs you can download (most you have to pay for), but you can download a freeware program called “PC Inspector Smart Recovery” from Snapfiles here
For those with SanDisk Extreme memory cards, SanDisk distributes software with their Extreme media called ‘RescuPRO’ which can also be used to recover your files. Pays to check out the little disks that come with your memory cards…who would have thought !
4. Install and recover !
* I’d also recommend installing the software on your laptop, so if your on the road/away you can recover on the go and not wait till you get home
* Take a spare card with you so you can still keep shooting.
Hope this helps !
For those interested in Geocoding their images, I thought I’d put together some information which may help.
I like to geocode my images with coordinates for a couple of reasons:
- I know exactly where I took the shot if I ever want to return; and
- I can add them to map applications like Google Maps as waypoints/points of interest, etc.
How to do it ?
—- —- —- —- —- —- —- ——
1) As long as you have a GPS device capable of recording your track it’s pretty easy from here.
2) I turn my GPS on before I start shooting and have it recording my track until I finish. So long as your able to create a GPX file afterwards, you can go to the next step.
3) Google have developed a geocoding tool which actually writes to your cameras raw files (*.CR2). I have not trialed a better app than this one – most only write to JPGs. Google’s product is free to download and use (as all great Google products are !!). You can download GPicSync here
4) If you do use the tool, just be mindful of time difference, i.e. GPS devices usually record tracks in UTC times, whereas your camera will probably set to your local time. The GPicSync application can be set to adjust for this in the configuration.
Hope this helps for those who are interested, enjoy.