What Is The Difference Between F And T Lenses?.
F-Stops vs T-Stops: What's the Difference, and Why Does It Matter?
Introduction
F-stops and T-stops are two important concepts in photography and videography. They both measure the amount of light that a lens allows to pass through to the image sensor, but they do so in different ways.
What is an F-stop?
An F-stop is a theoretical value that is calculated based on the diameter of the lens aperture. The larger the aperture, the smaller the F-stop number, and the more light the lens will let in. For example, a lens with an aperture of f/2.8 will let in twice as much light as a lens with an aperture of f/4.
What is a T-stop?
A T-stop is a measured value of the amount of light that actually reaches the image sensor, taking into account all of the factors that can affect light transmission, such as the lens coating, the number of lens elements, and the distance between the lens elements.
Why does T-stop matter?
T-stop is important because it allows cinematographers to accurately compare the brightness of different lenses, even if they have different F-stop numbers. This is essential for achieving consistent exposure from shot to shot.
How to choose between F-stop and T-stop lenses
If you are primarily shooting stills, then F-stop lenses are fine. However, if you are shooting video, or if you need to compare the brightness of different lenses, then T-stop lenses are the better choice.
Benefits of using T-stop lenses
- More accurate exposure: T-stop lenses allow you to achieve more accurate exposure from shot to shot, even if you are using different lenses. This is important for cinematography, where consistent exposure is essential.
- Easier to compare lenses: T-stop lenses make it easier to compare the brightness of different lenses, even if they have different F-stop numbers. This is useful for both photography and videography.
- Less light loss: T-stop lenses typically transmit more light to the image sensor than F-stop lenses. This is because T-stop lenses take into account all of the factors that can affect light transmission, such as the lens coating and the number of lens elements.
Drawbacks of using T-stop lenses
- Can be more expensive: T-stop lenses are typically more expensive than F-stop lenses.
- Less common: T-stop lenses are not as common as F-stop lenses, so they may be more difficult to find.
Conclusion
T-stop lenses are a good choice for cinematographers and photographers who need accurate exposure and consistent brightness from shot to shot. However, they can be more expensive and less common than F-stop lenses.
Additional information
Here are some additional things to keep in mind about F-stop and T-stop lenses:
- T-stop lenses are typically used in cinematography, while F-stop lenses are more commonly used in photography.
- T-stop lenses are often used in conjunction with other cinema equipment, such as light meters and ND filters.
- T-stop lenses are not always necessary for photography, but they can be useful for photographers who need accurate exposure and consistent brightness from shot to shot.
Examples of T-stop lenses
Here are a few examples of T-stop lenses:
- ARRI Prime DNA lenses
- Cooke S7/i lenses
- Panavision Primo lenses
- Zeiss Supreme Prime lenses
Examples of F-stop lenses
Here are a few examples of F-stop lenses:
- Canon EF lenses
- Nikon F lenses
- Sony FE lenses
- Tamron SP lenses
Which type of lens is right for you?
The type of lens that is right for you will depend on your specific needs and budget. If you are primarily shooting stills, then F-stop lenses are fine. However, if you are shooting video, or if you need to compare the brightness of different lenses, then T-stop lenses are the better choice.