Archived posting to the Leica Users Group, 1999/07/27
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Alex Brattell wrote: > > >perhaps a dumb question, but I keep running into "A4" size prints, etc, = > >etc. What are the "inch" equivalents to these "A-series" size prints? = > >Can someone clarify this? Are these standard "European" size prints, = > >and if so, does the "A" stand for anything?? Thanks, Kent > > Can't answer this - but I have an equally stupid question that I can't find > the answer for; > > What does the 'f' in f-stop stand for? > (I've asked people and looked in books, and had to admit to the person who > asked me - haven't got a clue!) > > thanks > alex > > ____________________________________________ > > alex@zetetic.co.uk > http://www.users.globalnet.co.uk/~abrattell/ > > ___________________________________________ Alex: The "f" in f-stop stands for focal length. If you have a 50mm lens and have it set at f/8, then the product of 50/8 (50 divided by 8) is the size of the opening made by the iris. In this example the lens opening at f/8 is 6.25mm. 100mm at f/16 has also a 6.25mm opening. Randolph Carlisle