Choosing the Right Lens for Low Light Video: F4 vs F2.8 and Prime Lenses

When it comes to capturing footage in low light conditions, the choice of lens can make a significant difference in image quality and overall performance. In this article, we explore the differences between an f4 24-105 mm lens and an f2.8 24-70 mm lens, as well as discuss prime lenses suitable for filming in close proximity where subjects are moving.

The F4 vs F2.8 Dilemma

In general, an f4 lens will not suffice for low light situations, especially when dealing with moving subjects. An f2.8 lens is more suitable, but even that can be challenging. Increasing your ISO can help to some extent, but it will introduce noise or grain in the image.

When considering the specific camera and lighting conditions, the choice of lens becomes even more nuanced. An f/1.4 prime lens is 3 full stops faster than an f/4 lens and 2 stops faster than an f/2.8 lens. This difference can be seen in classic filmmaking, such as the candle-lit scenes in Stanley Kubrick's Barry Lyndon, where an f/0.7 lens was used to capture these dim scenes. On a DSLR, an f/1.4 lens would allow for significantly lower ISO settings compared to f/2.8 and f/4 lenses, which can help reduce noise.

Understanding ISO and Noise

On a DSLR, the same shot would require ISO 800 at f/1.4, 3200 at f/2.8, and 6400 at f/4. The noise reduction capabilities of modern cameras have improved significantly over the past few years, but higher ISO settings still introduce more noise. This makes the f2.8 and f4 lenses less advantageous in low light conditions unless you have no other choice.

Prime Lenses for Low Light Video

For situations requiring filming in close proximity with moving objects, a prime lens can be highly beneficial. While the f2.8 24-70 mm lens offers some portability and flexibility, a prime lens such as the 50 mm f1.4 or f1.8 can be a better choice. These lenses are known for their ability to capture quality images even in low light and are relatively affordable, making them a great option for both hobbyists and professionals.

Here are a few key points to consider:

F2.8 is two stops faster than f/4.0. In the digital world, this difference can be less pronounced due to the high ISO capabilities of modern DSLRs. For capturing moving subjects in small clubs or similar settings, a prime lens can outperform a zoom lens. The f1.4 or f1.8 prime lenses offer better low light performance and can create a more shallow depth of field, allowing for a crisp subject against a blurred background. While some photographers may prefer the brightest lenses for image quality, it’s important to remember that not all fast lenses are sharp. Many professional photographers opt for faster primes for their performance in low light scenarios.

Should you find yourself shooting in low light conditions with moving subjects, consider investing in a prime lens. The 50 mm f1.4 or f1.8 lenses are typically priced reasonably and are well-suited for capturing high-quality video in challenging lighting environments.

Conclusion

In conclusion, while an f4 lens may seem sufficient at first glance, it often falls short in low light conditions, especially when moving subjects are involved. An f2.8 lens can be better, but prime lenses like the 50 mm f1.4 or f1.8 are often the best choice for capturing high-quality video in those challenging situations.