Enter the equivalent focal length (mm) into the Calculator. The calculator will evaluate the Shutter Time.
Shutter Time Formula
ST = 500 / EFL
Variables:
- ST is the Shutter Time (seconds)
- EFL is the equivalent focal length (mm)
To calculate Shutter Time, divide a value of 500 by the equivalent focal length in millimeters.
How to Calculate Shutter Time?
The following steps outline how to calculate the Shutter Time.
- First, determine the equivalent focal length (mm).
- Next, gather the formula from above = ST = 500 / EFL.
- Finally, calculate the Shutter Time.
- After inserting the variables and calculating the result, check your answer with the calculator above.
Example Problem :
Use the following variables as an example problem to test your knowledge.
equivalent focal length (mm) = 20
FAQ
What is equivalent focal length (EFL) and why is it important in photography?
Equivalent focal length (EFL) is a measure that describes how a lens will capture an image as if it were using a 35mm film or full-frame digital sensor. It’s important because it helps photographers understand how their lens will perform on different camera bodies, especially when comparing crop sensor cameras to full-frame sensors.
How does shutter time affect a photograph?
Shutter time, or shutter speed, determines how long the camera’s sensor is exposed to light. A longer shutter time can create motion blur, capturing the movement in a scene. A shorter shutter time freezes action. Adjusting shutter time is crucial for achieving the desired effect in a photograph, whether it’s a sharp, still image or a dynamic, blurred one.
Can I use the shutter time formula for any camera and lens setup?
Yes, the shutter time formula (ST = 500 / EFL) is a general guideline that can be applied to any camera and lens setup. However, the effectiveness and accuracy can vary based on specific factors like camera sensor size and the presence of image stabilization technologies. It’s a starting point that might need adjustments based on the shooting conditions and equipment used.
Why is a calculator for shutter time useful?
A calculator for shutter time is useful because it simplifies the process of determining the optimal shutter speed for capturing sharp images, especially in astrophotography or when using long lenses. It helps photographers quickly adjust settings in the field without having to manually calculate and potentially miss capturing a fleeting moment.
