Parfocal Lens – Definition & Detailed Explanation – Cinematography Glossary Terms

I. What is a Parfocal Lens?

A parfocal lens is a type of camera lens that maintains focus on a subject even when the focal length of the lens is changed. This means that when a cinematographer zooms in or out with a parfocal lens, the focus remains sharp and does not need to be adjusted. This is in contrast to non-parfocal lenses, where the focus must be manually adjusted every time the focal length is changed.

II. How does a Parfocal Lens differ from a Varifocal Lens?

A parfocal lens differs from a varifocal lens in that a varifocal lens does not maintain focus when the focal length is changed. Varifocal lenses are commonly used in security cameras and consumer camcorders, where the user may need to adjust the zoom frequently and does not require precise focus. In contrast, parfocal lenses are used in professional cinematography where maintaining focus is crucial for creating high-quality footage.

III. What are the advantages of using a Parfocal Lens in cinematography?

There are several advantages to using a parfocal lens in cinematography. One of the main advantages is that it allows cinematographers to zoom in and out without having to worry about adjusting the focus. This can save time on set and ensure that shots are captured quickly and efficiently. Additionally, parfocal lenses are known for their sharpness and clarity, making them ideal for capturing high-quality images.

IV. How do cinematographers maintain focus when using a Parfocal Lens?

While parfocal lenses are designed to maintain focus when the focal length is changed, cinematographers still need to ensure that their shots are in focus. One way to do this is by using a focus puller, who is responsible for adjusting the focus during a shot. Cinematographers can also use tools such as focus peaking or focus assist to help them achieve precise focus when using a parfocal lens.

V. What are some popular Parfocal Lenses used in the film industry?

There are several popular parfocal lenses used in the film industry, including the Canon CN-E 15.5-47mm T2.8 L S, the Zeiss Compact Zoom CZ.2 28-80mm T2.9, and the Angenieux Optimo Style 25-250mm T3.5. These lenses are known for their sharpness, clarity, and ability to maintain focus throughout the zoom range, making them popular choices among cinematographers.

VI. How can cinematographers achieve the best results with a Parfocal Lens?

To achieve the best results with a parfocal lens, cinematographers should practice using the lens and familiarize themselves with its capabilities. They should also work closely with their focus puller to ensure that shots are in focus and use tools such as focus peaking to help them achieve precise focus. Additionally, cinematographers should experiment with different focal lengths and apertures to create unique and visually stunning shots with a parfocal lens.