As a newbie, I’m constantly bashing the mathematical and logistical systems of photography. Why? Because I want things laid out simply and with the greatest of ease. The expectation of newbies like myself, is to pay good money for a camera and instantly become Ansel Adams or even a Fred Miranda. Why not? Would it not be great to write a check and become an instant celebrity? Would it not be great to wake up one morning with the years of mastery of the greats simply by making a purchase? Wishful thinking, of course…but it ain’t gonna happen for me. So, in the mean time, I reckon I’ll get my fancy photography learnin’ the ole fashioned way….. I’ll try…then I’ll try some more.
Let’s talk about Aperture. This bigger the F-stop, the smaller the aperture (opening). It can get confusing. I want to believe the opposite. Why? Because it would make it easier, but unfortunately, it would be ALL WRONG!
So here’s what ‘Sensei’ Kayne says from ProDslr.com:
“It would definitely be more intuitive for beginners, yes. But just like almost everything when it comes to photography, there is math involved. Having it done that way would be totally opposite when it comes to the mathematical equation that determines the f/ stop or aperture size.
The equation… in case you’re wondering is…
f/# = N = f/D
Where f equals the focal length of the lens and D equals the diameter of the entrance pupil of the aperture.
So basically… if the focal length is say 8 times the diameter of the entrance pupil… that is f/8.
Using your new 50mm lens as an example and plugging those numbers into the equation… at f/8 the diameter of the entrance pupil at the time of exposure is only 6.25mm.
Not very big… is it?
And that wouldn’t let a lot of light into the lens.
Where as at f/1.8 the diamater at the entrance pupil is 27.8mm(rounded up).
Which… of course… will let a lot more light into the lens at the time of exposure.
And considering the aperture size is yet another mathematical equation pertaining to an actual measured amount of how much light is let into a lens(Aperture Area)… Gary summed it up pretty good…
A 1 to 1 ratio is… theoretically… all the light that can be let into a lens.
And that… of course… would be f/1 __________________“
Ok, so you haven’t heard of Kayne, but who cares. He know’s what he’s talking about and for the most part, that’s all that matters.