5 Astrophotography Mistakes
Broad Haven Beach
I recently visited the Stackpole Estate in South Wales where the South facing Broad Haven Beach is conveniently located near to a National Trust Car Park.
Broad Haven Beach is within a 'Dark Skies' area of the UK and enjoys fairly low levels of light pollution. I took the opportunity to visit the beach at mid-night and try my hand at some astrophotography with the Fuji X-T2 and Fuji 16mm f1.4 and 10-24mm f4
Overall I was pleased with the shots that I took on this night and although I managed to get some things right there are a number of mistakes that I made that I will hope to avoid the next time out.
1) Not utilising Long Exposure Noise Reduction
When taking photographs of the stars or Milky Way it is important to keep the length of exposure short to avoid blur caused by movement of the stars during exposure. (It is useful to refer to the 500 rule to help calculate this for your lens - See Below)
It becomes necessary to use a high ISO even when using fast glass. I did not think to enable the 'Long Exposure Noise Reduction' feature on the X-T2 which would have helped reduce digital noise in the final image.
When using Long Exposure Noise Reduction it is necessary to expose for 20 seconds and then wait a further 20 seconds for the camera to complete the Noise Reduction Frame.. but this is not to inconvenient.
To achieve points of light you can use a simple rule that's often called the “500 Rule”. For example; let's say you're taking a shot with a 16mm lens on a full frame camera. 500 / 16 = 31.25 seconds, which you can round to 30 seconds.I was using a 16mm Lens on a Fuji X-T2. Taking into account the 1.5 crop factor of the APS-C sized sensor - This gives a guideline exposure of 21 seconds - 500 / (16 * 1.5 Crop Factor)
2) Not waiting until full dark
I visited Broad Haven around 11:30pm and stayed until around mid-night. I was on vacation with my wife and didn't want to let this diversion impact on the next days activities but it would have been better to shoot later in the evening when the light from the day had faded further.
You should reference apps such as PhotoPills to calculate the darkest point of the night.
3) Not taking into account lens performance artefacts @ f1.4
I used the excellent Fuji 16mm f1.4 for the photos of the Milky Way. I did not realize that the lens suffers from coma effects at the edges when stopped right down to f1.4
I should have taken some exposures at f2 or f2.8 to reduce the effect.
4) Not turning off 'Preview Picture Effect'
This is specific to mirrorless cameras. I should have thought to disable Preview Picture Effect for the LCD and IVF screens to ensure that I got an enhanced image to compose with rather than a preview of exposure (which was blank in the dark!)
I had to compose using 10 second exposures to trial and error the camera angle.
5) Not being fully prepared to manual focus
While I did some research on methods of focusing in the dark I should have experimented further with the 16mm to ensure that I was confident on manual focus to infinity. The 16mm f1.4 has a focus scale which should make this straight forward.
I was photographing with an aperture of f1.4 and I tried a number of methods on the night to focus correctly. This is the wrong time to be experimenting and I missed some shots due to mistakes