What’s an F’ing F-stop?
For those of you wanting to learn a little more about shutter speeds and f-stops, whether to increase your photographic knowledge or looking to take manual control of your camera – read on.
We will explain in simple terms some of the technical aspects of photography which may improve your exposures or, if nothing else, help you determine where you are going wrong.
As the chart suggests (Credit; Hamburger Fotospots), there are three factors that we have some control over, which can effect an exposure:
- The F-Stop
- The Shutter Speed
- The Film Speed or ISO/ASA
The F-stop is a measurement of the aperture of the lens and can allow more or less light into the lens and then onto the film. The higher the F-stop number (F16 or F22) the smaller the aperture and so less light is allowed in. A lower F-stop number (F2.8 or F4) the wider the aperture so more light is allowed in.
The aperture is likened to the iris of the human eye – in bright light the iris will contract, leaving a small hole but in low light situations the iris opens wide to allow more light in, to hit the retina which is the equivalent of the film (kind of!)
As the chart suggests the differing F-stops affects the depth of field, so where we have the choice we can determine whether the whole scene is in focus or just a part of it, assuming we know how to focus the lens!!
The shutter speed is, put simply, the amount of time the reflected light from the subject is allowed to hit the film. Shutter speeds can range from a fast 1/1000 of a second (sometime even faster depending on the camera) to a slow 1/4, 1/2 or even full second and some cameras have a Bulb (B) setting which allows you to leave the film exposed for as long a you like – in the case of astrological photography it can be all night!
Different shutter speeds can be used to effect. A fast shutter speed will capture action, and slow used to blur motion as the diagram depicts. A rally car will be caught mid flight over the hump of a road with a fast shutter speed and conversely moving water will take on a dream like blurred quality with a slow shutter speed.
This shot was taken with a fast shutter speed and captured the swimmer mid-air as he is diving into Bronte Baths.
This image was taken at night, on a tripod, and with a slow shutter speed resulting in the Sydney Light Rail train being blurred. Both images were shot on Candido film. https://www.instagram.com/candidocollective/?hl=en
The third variable in photography is the Film Speed and when considering film photography it is a variable that needs to be decided once the film selection is made as it will last for the whole roll!
So put simply, slow (100ASA/ISO) film would generally be selected for a well lit sunny scene and fast film (800/1600 ASA/ISO) for low light situations such as a restaurant interior or a beach at sunset and even then a flash may still be necessary to render an image visible on film.
The other quality of higher speed film is that it sometimes exhibits grain when processed in the negative and in the scan/print. It’s a love it or hate it with most people but be aware it’ll be there!
