From Total Noob to Astrophotographer: Guidance for Sony a6700 Users

Embarking on the journey of astrophotography can feel daunting, especially when faced with impressive celestial images and your own initial attempts. Many aspiring night sky photographers begin with a common set of questions, and this post aims to provide clarity, drawing from real-world experiences and advice shared within the community.

The Challenge: Settings and Light Pollution

A new photographer shared their recent attempt at capturing the night sky using a Sony a6700 with a Sigma 18-50mm lens. The settings used were 30 seconds of exposure, ISO 5000, and an aperture of f/20. While the photographer acknowledged significant light pollution from a nearby airport, they were hoping for better results and were seeking guidance.

Key Settings for Stellar Results

Aperture: Go Wide!

A crucial piece of advice for astrophotography is to never shoot at f/20. This aperture setting severely restricts the amount of light entering your camera. For capturing faint celestial objects, you want to let in as much light as possible. This means shooting with your lens as wide open as it can go, often referred to as its "fastest" aperture. For the Sigma 18-50mm lens, this is typically f/2.8.

Stopping down the lens significantly, as was done at f/20, not only reduces light but can also negatively impact image sharpness. For astrophotography, aim for f/2.8 or perhaps f/3.5 at the slowest. Experimenting with different wide apertures will yield a much better starting point for your images.

Exposure Time: Avoiding Star Trails

While longer exposure times are necessary to gather light, 30 seconds can sometimes be too long, leading to visible star trails. These trails occur because the Earth is constantly rotating, and over a prolonged exposure, the stars appear to move across the sky.

To combat this, it's recommended to shorten your exposure time. Try starting with exposures of 10, 15, or 20 seconds. After taking a test shot, zoom in on the stars to ensure they appear as sharp points rather than elongated streaks. Adjusting the exposure time iteratively will help you find the sweet spot between capturing enough light and maintaining sharp stars.

Overcoming Light Pollution

Light pollution is a significant challenge for astrophotographers. While post-processing tools like Adobe Lightroom can help mitigate some of its effects, they cannot magically create detail where none exists. The best approach is to minimize light pollution at the source by:

• Location Scouting: Finding darker skies away from urban centers is ideal.
• Timing: Shooting during moonless nights can also improve image quality.
• Camera Settings: As discussed, using the widest aperture and appropriate exposure times will maximize the light from faint objects, making them stand out more against the ambient light.

Moving Forward

By adjusting your aperture to f/2.8 and experimenting with shorter exposure times (around 10-20 seconds) while keeping your ISO at a manageable level (experimenting with ISO 3200 or 6400 while watching for noise), you'll be well on your way to capturing stunning night sky images. Don't be discouraged by initial results – astrophotography is a skill that develops with practice and understanding of your equipment and the night sky itself.

Happy shooting!