How to Calculate the Effective Focal Length for Panasonic GH5 with Metabones Speed Booster
Photographers often use accessories to further enhance their lenses, such as the Metabones T Speed Booster Ultra 0.71x. This article explains the necessary steps to calculate the effective focal length of a lens when used with a Panasonic GH5 camera and the Metabones Speed Booster Ultra. While some find arithmetic daunting, this guide aims to simplify the process for all enthusiasts.
Understanding the Components
When using a camera system with a crop factor, such as the Micro Four-thirds sensor in the Panasonic GH5, the effective focal length of the lens changes. The Metabones T Speed Booster Ultra 0.71x introduces its own focal length multiplier, which must be factored in to determine the effective focal length. Let's break down these components:
1. Identifying the Lens Focal Length
The first step is to determine the original focal length of the lens you are using. Lens focal lengths are usually listed in millimeters (mm) and can range from very short (wide aperture lenses) to very long (telephoto lenses). For this example, let's assume a lens with a focal length of 50 mm.
2. Applying the Speed Booster Factor
The Metabones T Speed Booster Ultra has a focal length multiplier of 0.71x. To calculate the effective focal length with the Speed Booster, multiply the original focal length by this factor.
The formula for calculating the Effective Focal Length (EFL) is:
Effective Focal Length Lens Focal Length times; 0.71
3. Considering the Crop Factor
The Panasonic GH5 has a micro-four-thirds sensor, which has a crop factor of 2x. To find the full-frame equivalent focal length, multiply the effective focal length by the crop factor.
The formula for calculating the Full-Frame Equivalent Focal Length (FFEFL) is:
Full-Frame Equivalent Focal Length Effective Focal Length times; 2
Example Calculation
Let's walk through an example calculation using a 50 mm lens with the Metabones T Speed Booster Ultra on a Panasonic GH5.
Lens Focal Length: 50 mm
Effective Focal Length:
50 mm times; 0.71 35.5 mm
Full-Frame Equivalent Focal Length:
35.5 mm times; 2 71 mm
Using a 50 mm lens with the Metabones T Speed Booster Ultra on a Panasonic GH5 gives you an effective focal length of 35.5 mm, which is equivalent to 71 mm in full-frame terms.
Simplifying the Process
Some enthusiasts might find the calculations a bit complicated, but we can simplify the process for a quick and easy solution. The Metabones T Speed Booster Ultra results in a new crop factor of 1.4x (2 times; 0.71).
This means that the advertised focal length will be 1.4x longer than it is specified. Therefore, the new focal length can be calculated as follows:
Example Calculation:
For a 50 mm lens:
50 mm times; 1.4 70 mm
For a 100 mm lens:
100 mm times; 1.4 140 mm
For a 200 mm lens:
200 mm times; 1.4 280 mm
Conclusion
The Metabones T Speed Booster Ultra is a powerful accessory that modifies the focal length of lenses designed for non-Micro Four-thirds camera systems. By following the steps outlined in this article, you can accurately determine the effective focal length of your lens when using it with a Panasonic GH5 and the Metabones Speed Booster Ultra.
Understanding the impact of the Speed Booster and the crop factor of the camera is essential for capturing the intended image. If you have any further questions, feel free to consult the camera and lens manuals or reach out to the community for more information.
Keywords: focal length, Panasonic GH5, Metabones Speed Booster