What Special Considerations Should Be Made When Shooting Starry Skies With A Short Focal Length Lens

Short focal length lenses offer a short focal length, wide angle of view, and large depth of field, making them suitable for shooting various scenes such as landscapes, architecture, and interiors. So, what precautions should be taken when using a short focal length lens to photograph the starry sky?

When shooting the night sky with a short focal length lens, the following key points need to be kept in mind:

1.Equipment selection and proper setup

(1)Focal length and aperture: The focal length of a short focal length lens is generally below 24mm. Prioritize a large aperture (such as f/2.8 or f/1.8) to increase the amount of light entering the lens, which is useful for capturing faint starlight. Shorten the exposure time to reduce star trails and lower the ISO setting to reduce noise.

(2)Shutter speed setting: The shutter speed should follow the “rule of 500” (shutter speed = 500 / focal length) to avoid star trails. It should be noted that this rule is based on full-frame cameras. In practice, a more conservative “rule of 400” or even “rule of 300” may be used. Following this rule, the exposure time should generally be no less than 20 seconds.

(3)Use a sturdy tripod and cable release: Astronomical photography requires long exposures, demanding extremely high stability. While short focal length lenses are less bulky than telephoto lenses, long exposures still require the assistance of a tripod to prevent blurry images. It is recommended to choose a tripod with high load-bearing capacity and stability, and to trigger the shutter via a cable release or remote control to avoid direct contact with the camera, which could cause camera shake and affect image quality.

(4)Shoot in RAW format: To retain more image data for easier post-processing, it is recommended to shoot in RAW format. RAW format offers higher dynamic range and detail retention, allowing for more flexibility in adjusting brightness, contrast, and saturation during post-processing.

2.Choose a suitable shooting location

Short focal length lenses are suitable for shooting wide-angle astrophotography and are more likely to capture city lights. It’s essential to choose dark environments away from urban areas to avoid light pollution, such as mountainous regions, beaches, or remote areas. These places have less light pollution, which helps capture clearer details of the starry sky. If it’s impossible to avoid light pollution, you can use foreground elements (such as trees or mountains) to block the light source.

3.Precise manual focus

In low-light conditions, autofocus is essentially ineffective, requiring you to switch the lens to manual focus mode and adjust the focus ring to infinity (∞) to ensure stars are sharp. The infinity position of some lenses may vary depending on the focal length, so it’s necessary to test and mark it beforehand. Therefore, it’s recommended to conduct several test shots to adjust focus and exposure parameters before the actual shooting.

4.Avoid interference from moonlight, clouds, etc

For astrophotography, it’s recommended to shoot around the new moon or after the moon has set to minimize the impact of moonlight on the night sky. Moonlight reduces the contrast of the night sky, making stars appear blurry. Additionally, it’s important to choose a clear, cloudless night to ensure the sky is sharp, as clouds scatter light and affect the clarity of the starry sky.

5.Foreground composition and creativity

The wide field of view provided by a short focal length lens can easily make the image appear empty; shooting only the sky can lack visual focus. Therefore, when shooting, utilize a wide perspective to include an attractive foreground, such as mountains, unique rocks, trees, buildings, or lake reflections.

If the foreground remains too dark after a long exposure, use a flashlight or LED light for fill light. The foreground is one of the key elements to the success of a starry sky photograph. Its presence not only enriches the content of the image but also helps guide the viewer’s eye.

6.Note the key points of post-processing

After shooting, post-processing can be done to further optimize the starry sky photo by lowering the color temperature, increasing contrast, saturation, and sharpness, such as brightening the starry sky and correcting color differences. For complex scenes, multiple photos with different exposures can be layered to balance details in the starry sky and foreground. It’s important to avoid over-processing, as this can result in harsh starlight or exaggerated noise; maintaining a natural texture is best.

In short, by controlling various key details, a short focal length lens can be used to capture starry sky works with a wide field of view and dense star points. Combined with some creative composition, it is not difficult to create starry sky works with a sense of story.