Excellent video explaining f stop on youtube.

A friend linked me to this video on Gizmodo. I am providing the direct link to youtube.

http://www.youtube.com …_embedded&v=KmN​IouLByJQ#!

Many of us use F Stop and such without truly understanding what it is actually doing. This video explains it beautifuly.

The same person also has video's for Depth of Field
http://www.youtube.com …m7Ew&index=2&fe​ature=plcp

And ISO

http://www.youtube.com …m7Ew&index=3&fe​ature=plcp

Arcsylver wrote in post #14203796
A friend linked me to this video on Gizmodo. I am providing the direct link to youtube.

http://www.youtube.com …_embedded&v=KmN​IouLByJQ#!

Unfortunately he made a common photographer mistake and believes that each full F stop change doubles or halves the amount of light allowed through the lens to hit the film or sensor, which is really not true due to the T factor of the lens, he also mentions that the F stop of one lens allows the same amount of light to pass through as the F stop of another lens which is only true if comparing two exact lenses, this again is due to the T factor of the lens may not so.

Depending on the construction and or focal length of the lens, at the same F stop one type of lens may actually allow more or less light to pass through than another.

Now if one knows the T factor of ones lenses then such statements are quite true, as the T factor is based on the amount of light that actually makes it through the lens, not a mathematical ratio between focal length and aperture, which fails to take into account the construction of, type of glass, and number of elements utilized in a lens.

Wayne

Channel One is correct. Transmission of light through a lens (T Factor) is influenced by such factors as the glass (material) used, the grinding method, the number of elements, the coatings, etc.

However, I think the video serves its purpose which is obviously to educate those who do not fully understand this aspect of exposure which means it had to be done on a simplistic level and not that of hard specs for gearheads.
.