First, post what aspect you plan to research of how mathematics relates to photography.  You may chose some other aspect besides the ones I listed in my example on the home page.  This posting is due by midnight on Sunday, April 6.  Be sure to sign your posting with the screen name you gave me.

I plan to research aspects of photography that involve the use of math. Manual cameras use mechanisms that control light exposure to film. This is called the lense, and it operates with mathematics by the timing and size of the opening. Ill be researching aperture and shutter speeds.

-loren

Okay, Loren.  Didn't you tell me someone would be doing this page with you?  E. Cohen

I will write about how the focal length of a camera and the object distance will determine where the image is created and what the magnification of the image is.  A mathematical equation called the thin-lens equation relates focal length, object and image distance. If the object and image distance are known the magnification can also be calculated. For a camera it is necessary that the image is a lot smaller than the object (e.g. you need to fit the Eifel Tower on 35 mm film or an even smaller detector in a digital camera). Also the image needs to be a real image, else it can not be made visible on film. 

hymenoxys

Thin-lens equation:

f is the focal length of the lens. 1/f is also called the refractive power of the lens. do is the object distance and di is the image distance. The lateral magnification of the image as defined as the ratio of image height over object height can be calculated as

Since the lens of the camera has to create a real image, this image will be on the other side of the lens than the object.

According to a convention the image distance is a positive value if the image is real and negative if the image is virtual. If di is positive then the magnification is negative. According to the convention this implies that the image created on the film or detector is inverted (upside-down) as compared to the object. To get a image that is reduced in size as compared to the object you need that the object distance is more than twice the focal length.

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