Another tertiary effect of aperture is in the creation of starbursts. Some lenses are more susceptible than others to this effect, but the general idea is that one can get a pleasing (or not) starburst at smaller apertures. Like this: Some photographers use this tertiary effect. There are filters available that create starbursts at any…
Category: Aperture
Tertiary effects: Diffraction
Another tertiary effect that photographers are aware of is something called diffraction. This occurs when you have a very small aperture—the light is actually diffracted by the iris in a way that can be seen in the photograph. Generally, this effect is not desirable since it affects all the light in the image—nothing is perfectly…
Secondary effects: Bokeh (暈け)
Photographers have taken a word from Japanese, bokeh (暈け), pronounced “BOW-kah”), to describe the quality of the out-of-focus regions in a photograph. Bokeh is roughly translated as “blur.” Photographers judge the quality of the bokeh in photographs. Here is a comparison of three different lenses’ bokeh. Most people consider the left image to have the…
Secondary effects: Aperture
Once again, aperture is the hardest leg of the exposure triangle to understand. Long story short: Large apertures tend to put the background out of focus; Small apertures tend to have more of the scene in focus. The flower on the left was shot with a large aperture, f/4. The one on the right was…
Putting it all together: Exposure
“Exposure” is the choices made in the Exposure Triangle and how it looks in the final picture. An image is properly exposed when it is not too bright and not too dark.[1] Here is an image I took on July 9, 2014. The exposure triangle settings for this image were: Aperture: f/6.3 Shutter Speed: 1/800…
How Aperture Relates to the other legs of the Triangle
The other aspect of aperture that is complicated is how it relates, numerically, to the other values in the exposure triangle. Hang with me here! Or take my word for it and skip ahead. Let’s say we have that 3 inch simple lens that is 1 inch across. What if we doubled the size of…
What is a “Stop”?
Now we can answer why we use the word “stop” in talking about exposure. On old cameras with a manual aperture ring, the aperture numbers are marked on the ring, similarly to the picture show above. On these old lenses, there was a mechanical click, or “stop,” built in to the action of that ring.…
Primary Effects — Aperture: Values
Values for the aperture are written as a fraction, like this: f/1 (Large aperture; lets in a lot of light) f/1.4 f/2.0 f/2.8 f/4 f/5.6 f/8 f/11 f/16 (Small aperture; lets in only a little light) The aperture can be any value. But in practice, these values are the most common ones that are quoted. …
Primary Effects: Aperture — Derivation of the numbers used for Aperture
The aperture is measured in a very funny way that is somewhat hard to understand.[1] The aperture is defined with respect to the focal length of the lens: A = f/d Where: A is the aperture value f is the focal length of the lens[2] d is the diameter of the opening of the lens…
Primary Effects: Aperture — Introduction
Aperture is, far and away, the hardest leg of the exposure triangle to understand. The aperture is the size of the opening in the lens. Only light that goes through that opening can hit the sensor. You can see the aperture variation on a large camera in manual mode—it is same way as the iris…