What is a Focus Chart, anyway?

What is a Focus Chart, anyway?

Mastering Your Lenses: The Power of Focus Charts

In the world of cinema, capturing the perfect shot is an art form. Whether you're an amateur enthusiast or a seasoned pro, there's a simple yet powerful tool that can take your shots to the next level – the trusty focus chart.

Focus Chart Basics

So, what exactly is a focus chart? Think of it as your lens's best friend. It helps you understand how your lenses work and ensures your shots turn out the way you want. Here's the lowdown:

  1. Solving Distortion Mysteries: Sometimes, things don't quite look as they should. You might notice something called "moustache distortion," where straight lines appear slightly curved. Or there's "barrel distortion," where the edges of your frame seem to bulge. These quirks can be frustrating, but a focus chart is your detective. It helps you figure out which lenses suffer from distortions so you're not left guessing while on a shoot. Fixing it might not be possible since lenses are very technical, but knowing this about your set of lenses is a very good starting point.

  2. Getting to Know Your Lenses: Your lenses aren't just pieces of glass – they have their own personalities. Each lens has its quirks and unique characteristics. A focus chart allows you to understand your lenses better, like getting to know a new friend. You learn how they behave, which helps you make the most of their strengths and work around their weaknesses.

  3. Check for chromatic aberration: You may have come across this issue. It's when you're shooting a high-contrast scene, like trees against a bright afternoon sky, and suddenly you notice strange purple or blue fringes around the objects – not a pleasant sight. This problem is known as chromatic aberration and is often found in older vintage-style lenses used in filmmaking or photography. In simple terms, these lenses struggle to bring all colors into focus at the same point, resulting in these unsightly fringes around high-contrast areas. It's essential to identify which lens exhibits poor chromatic aberration performance when working on a film set. A focus chart can be a valuable tool for this purpose. It typically features a white background with black shapes, creating a high-contrast area that helps you spot this issue in your footage.

Sharper Shots, Clearer Vision

So, why should you bother with a focus chart? Here's why it's a game-changer:

  • Sharper Shots: A focus chart helps you achieve sharp, clear shots. Doing a thorough lens test can help with finding back-focus issues and, of course, help fix them. 

  • Distortion Fixes: If your lens is giving you those bent lines or bulging edges, the focus chart is there to guide you.

  • Lens Mastery: Whether you have a collection of lenses or just one trusty one, a focus chart helps you master them all. You'll learn their quirks and how to work with them to get the results you want.

In Conclusion

Many people now own various vintage lenses. These lenses are often acquired individually, from different sources, countries, and eras. This can lead to a wide range of characteristics. Using a focus chart helps you determine if your 19mm lens behaves similarly to your 35mm lens or your 35mm lens compared to your 80mm lens. Having a clear understanding of your lenses' performance is crucial when working on a film set.

Using a focus chart might sound a bit technical, but it's a simple and valuable tool for anyone who loves taking photos or shooting videos. It's like having a secret recipe for picture-perfect shots. Whether you're dealing with moustache distortion, barrel distortion, or simply want sharper images, a focus chart has your back. It's your window into the fascinating world of lens behavior, and it empowers you to create stunning visuals with confidence. So, grab your camera, your lenses, and your trusty focus chart, and start capturing those picture-perfect moments!


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Filmmaker, YouTuber & Founder of Filmmakers Community

Sjoerd Wess is a YouTuber and filmmaker who lives in the Netherlands, one of the flattest countries in the world. He initially studied sports but discovered his passion for filmmaking when he started skateboarding at the age of 13. Nowadays, his primary focus is on creating documentaries, national TV series, and thrilling outdoor projects like snowboarding and surfing.

To give back to the filmmaking community, Sjoerd founded the Filmmakers Community. It's a space where people can come together to learn from each other, share their work, clips, knowledge, and much more!