Quick Tip: What is an F-Stop?

F-Stop is NOT an f-word

What exactly is an f-stop anyway?

The term f-stop is sometimes confusing due to its multiple meanings. In photographic terms it can mean the size of a lens aperture or an EV (Exposure value) of light.

Lens aperture -corresponds to the aperture opening of the lens. The smaller the number the bigger the aperture opening. An f/2.8 has a bigger opening then f/8. When you open up a lens by one stop you allows twice as much light into the camera.

The list below shows a typical progression of f-stops. For those techies out there it corresponds to the sequence of the powers of the square root of 2.

f/1, f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, f/32

EV (Exposure value) – represents a doubling or a halving of the light exposure either by stopping up or down of the lens aperture or by changing the shutter speed.

By speeding up or slowing down the shutter speed you effectively increase or decrease the amount of light that will enter the camera.

The shutter speed times are actually a fraction of a second. A speed of 1/125 (or simply 125th) really means 125th of a second.

Comments

, ,

6 Responses to Quick Tip: What is an F-Stop?

  1. Hermes replica May 4, 2013 at 9:16 am #

    Hello, your articles here March 2010 – Photography Tip Of The Month | R. Mabry Photography to write well, thanks for sharing

  2. Anonymous March 6, 2014 at 11:56 am #

    So, to be more clear, in regards to EV, one would “speed up” the shutter speed by changing the shutter speed setting from 8 to 60, for example, thereby allowing less exposure time of light to the film, and conversely, to “slow down” the shutter speed one would change the shutter speed setting from 60 to 8, for example, to allow more exposure time of light to film. Your definition was confusing to me. Which was which?

  3. Antwon October 27, 2015 at 6:19 pm #

    You know you need a shutter speed of at least 1/500s to get the aciton to freeze, so you might as well set your shutter speed to that value. Now it’s merely a matter of finding the right ISO speed and aperture to balance everything out. At 1/500s, not that much light is entering the camera, so you had better be using a wide open aperture or a bigger ISO speed.

Trackbacks/Pingbacks

  1. R. Mabry Photography : May 2010 - Photography Tip Of The Month - May 6, 2010

    […] a previous article (F-Stop is NOT an F-word) I explained the nomenclature commonly used for aperture is f-stop.  Aperture and f-stop relate to […]

  2. Tweets that mention R. Mabry Photography : March 2010 - Photography Tip Of The Month -- Topsy.com - May 6, 2010

    […] This post was mentioned on Twitter by Ray Mabry. Ray Mabry said: New blog post: March 2010 – Photography Tip Of The Month http://www.rmabryphotography.com/blog/march-2010-photography-tip-of-the-month/ […]

  3. Quick Tip: Aperture and Depth of field | R. Mabry Photography - May 6, 2015

    […] a previous article (F-Stop is NOT an F-word) I explained the nomenclature commonly used for aperture is f-stop.  Aperture and f-stop relate to […]

Leave a Reply

Powered by WordPress. Designed by WooThemes