Choosing the Perfect Lens for Night Sky Photography: Rokinon 24mm f1.4 vs Rokinon 14mm f2.8
Introduction to Night Sky Photography
Night sky photography captures the beauty of the universe, from star trails to constellations, providing a unique view of our cosmos. When it comes to choosing the right lens, the decision often hinges on the focal length and aperture, two critical factors in achieving the best possible results. In this article, we will compare the Rokinon 24mm f1.4 and Rokinon 14mm f2.8, providing insights for photographers looking to capture stellar images of the night sky.The Role of Aperture and Focal Length in Night Sky Photography
The focal length and aperture of a lens significantly influence the quality and versatility of night sky photographs. The 24mm f1.4 lens is more suitable for capturing large portions of the night sky, including star trails and wide-angle landscapes, thanks to its wider angle of view. On the other hand, the 14mm f2.8 lens offers a more dramatic and immersive experience, making it ideal for landscape configurations and other astrophotography projects.Comparing the 24mm and 14mm Lenses
Rokinon 24mm f1.4 Lens: A faster lens with a wider aperture (f1.4) and a longer focal length (24mm), this lens provides superior low-light performance. At f1.4, the lens captures more light, allowing for shorter exposure times and reducing star trail visibility. However, its longer focal length requires adjustments to exposure times to prevent star trailing, especially when using the popular 500 rule.
Using the 500 Rule
The 500 rule is a popular technique in astrophotography to estimate the exposure times needed to avoid star trailing. The rule states that the exposure time in seconds should be 500 divided by the focal length of the lens in millimeters. For a full-frame camera, the effective exposure time for the 24mm lens is calculated as follows:500 / 24 ≈ 21 seconds (using the 500 rule)
For a crop sensor camera with a 1.6 crop factor, it would be:500 / (24 * 1.6) ≈ 13 seconds (using the 500 rule)
Using a similar approach with the 600 rule, which is more conservative, the exposure times would be approximately 16 seconds and 10 seconds, respectively.Comparing with the 14mm f2.8 Lens
The 14mm f2.8 lens, while slower at f2.8, offers a wider field of view. Using the same formula, the effective exposure time for the 14mm lens with a 1.6 crop factor becomes:500 / (14 * 1.6) ≈ 23 seconds (using the 500 rule)
Again, using the 600 rule, the exposure times would be approximately 27 seconds and 17 seconds, respectively.The 24mm f1.4 lens being 2 stops faster than the 14mm f2.8 lens means that it can register more of the night sky within a given ISO range, even though it requires shorter exposure times to avoid star trailing. However, it can fall short in capturing longer star trails and wider landscapes.
Stacking Images for Better Results
To achieve optimal results in astrophotography, photographers often stack multiple images. This technique helps reduce noise and improve overall image quality. The faster 24mm f1.4 lens, while potentially registering star movements more easily, still captures high-quality images within a shorter exposure time. This makes it more versatile and efficient, particularly in astrophotography with APS-C cameras, where the number of images that can be captured in a given time frame increases.Personal Preferences and Use Cases
Ultimately, the choice between the Rokinon 24mm f1.4 and Rokinon 14mm f2.8 depends on personal preference and specific use cases. While the 24mm f1.4 excels in capturing large portions of the night sky with less noise, the 14mm f2.8 offers a more immersive and dramatic effect, especially for landscape configurations.Many photographers, like rob, prefer the Rokinon 24mm f1.4 for its versatility and wide angle of view. However, the 14mm f2.8 is a favorite for those who value wide-angle, dramatic framing, and want to capture the night sky with a more immersive perspective.