Why is aperture backwards??

[carterspaul555]

So, I get that larger f numbers like f/22 actually mean that it's a smaller opening and that smaller f number like f/2 is a big opening. I learned that thanks to a really helpful beginner video I just watched - https://www.youtube.com/watch?v=fpdxMUWF0k0. But my question is this...WHY is the size of the aperture backwards from the numbers. Shouldn't f/22 be a big aperture since it's a big number and f/2 should be a small aperture since it's a small number???

[DanK]

This site has superb tutorials. (Look at the bar toward the top.) This is explained here: https://www.cambridgeincolour.com/tu...a-exposure.htm.

[Manfred M]

The aperture is the ratio of the focal length of the lens to the diameter of the entrance pupil; the smaller the the entrance pupil when the lens is stopped down, the larger the f-stop number.

[pschlute]

Shouldn't f/22 be a big aperture since it's a big number and f/2 should be a small aperture since it's a small number???

In mathematics which do you consider the bigger number : 1/2 or 1/22 ?

[xpatUSA]

... But my question is this...WHY is the size of the aperture backwards from the numbers? Shouldn't f/22 be a big aperture since it's a big number and f/2 should be a small aperture since it's a small number???

Welcome! In case you haven't got it yet:

The size of the aperture is backwards from the numbers because of the forward slash between "f" and the number which makes the number a divisor. As has already been said - the bigger the divisor, the smaller the result.

Hope that helps ...

In these days of less pedantic grammar, some people have taken to leaving out that forward slash - such that we now get to read crap like "F4" which, in my world, is still a Douglas Phantom fighter jet ...

[William W]

I expect you now have all the tools for a good understanding of why, on any one lens, F/22 is a smaller aperture than F/2.

Another area of confusion with large and small numbers is possibly worth noting now: it is about Shutter Speeds when the terms “fast shutter speed” and “slow shutter speed” are used.

Note that 1/1000s is a relatively FAST Shutter Speed and 1/2s is a relatively SLOW Shutter Speed.

Importantly though, note that 2 seconds is a FASTER Shutter Speed than 8 seconds.

WW

[William W]

. . . In these days of less pedantic grammar, some people have taken to leaving out that forward slash - such that we now get to read crap like "F4" which, in my world, is still a Douglas Phantom fighter jet ...

That made me giggle: I expect "The F16 Rule" would take on a whole new meaning.

WW

[ST1]

It seems that the OP has also asked the same question on another photographic forum (ephotozine.com)

It made me wonder why they would do so. Did they not like the response they received from one or the other forum

[davidedric]

Also on DPReview!

[DanK]

I've seen this before: someone, often a newbie, broadcasts a question across a bunch of forums without waiting to see what s/he gets in one. Perhaps because I so often experienced something similar in my work, I find this annoying because it places no value whatever on the time of the people who respond. A related problem is people who post a question as a substitute for doing a simple search; rather than reading something already written, they ask strangers to take the time to write it again. (This was such a case; there are countless explanations on the web, including one right here on this site.) This is very different from reading and introduction and finding something unclear; that's a good use of a forum. That's why I sometimes tell people here to read the relevant tutorial here first and then post their questions. The tutorials are usually more complete and clearer than our ad hoc answers, and it's not considerate to ask half a dozen people to take the time to replicate what's already written.

Because of what I did in my career, I often experienced another variant of this. Total strangers would contact me asking for a phone conversation to answer a question that they clearly hadn't read about. Indeed, in many cases, they had read nothing relevant at all; they had just done enough of a search to find a relevant name. Over time, I became increasingly annoyed by this, and sometimes I sent people either pdfs or citations, telling them to get back in touch only after they had read them.

Enough for this morning of being a grumpy old man.