What is the correct way to express aperture and focal length?

[Heroique]

Also is it “len’s aperture” or “lens’s aperture” for a single lens?

And it is the lens’ aperture.

You can do what you like with the numbers, but it’s “lens’ aperture.”

Vaughn and polyglot got it right: “lens’ aperture.”

“Lens” is singular. [i.e., no apostrophe, as in: “lens aperture”]

Oren is correct. Lens is singular, and no possessive is either needed or wanted.

It’s only a matter of time before someone recommends “lens’s aperture,” but for now, “lens’ aperture” is clearly winning – with support for “lens aperture” (no apostrophe) picking up steam.

And if it was “lense” – whoops, sorry – if it were “lense,” should one use an apostrophe? If yes, should it be “lense’ aperture,” or should one also add an “s”? And if one should add an “s,” should the “s” come before the apostrophe (“lenses’ aperture”) or after the apostrophe (“lense’s aperture) – or, should one add neither an apostrophe nor an “s” (“lense aperture”)?

Finally, should the commas in the paragraph above that appear before the quotation marks (‘ “lense,” ’) actually come after the quotation marks ( ‘ “lense”, ’)? And in the preceding sentence, when I type “ ‘ “lense,” ’ ” and “ ‘ “lense”, ’ ” – embedding quotation marks – would it be more clear to use two types of quotation marks as I have done (“ ” & ‘ ’), or only one type (either “ ” or ‘ ’)?

[Oren Grad]

Originally Posted by Oren Grad

[i.e., no apostrophe, as in: “lens aperture”]

Uh, no, I didn't say that. Or mean it.

Cheers...

[Struan Gray]

"f/2.8" is the 'proper' way to write photographic apertures.

Perhaps worth noting is that most of the optics textbooks intended for physicists call this the 'f-number' or 'focal ratio'. That's because there is another definition of aperture used in microscopy (and radiometrics) which is called the 'numerical aperture'. Just saying "lens' aperture" is ambiguous in wider contexts than pure photography.


PS: on eBay, of course, one should use "lenses's aperature".

[Heroique]

Len’s aperture is correct.

If Len chooses another, his image will suffer.

Let’s not question Len’s aperture.

[Doremus Scudder]

Oh boy, great topic; it takes me back to my days of discussing my dissertation with my doctoral committee... Nevertheless, it's worthwhile.

Manufacturers tend to use the ratio to express maximum aperture, e.g., 1:5.6 (for terms expressed in English) or 1:5,6 (for German and most other European languages, the comma replaces the decimal point). One would pronounce it "one to five-point-six" (oder "eins zu fünf-komma-sechs").

For a particular aperture setting within the aperture range, I like to use "f/," as in f/22, f/64, etc. This shows the fraction of the focal length by using the diagonal and is easy to type as well as understand; "f:32" seems easy enough to understand as well, but appears less used.

Designating a particular lens "Nikkor W f/5.6 210mm" is perfectly understandable, but I don't mind reversing the terms either, as in "Wide-field Ektar 135mm f/6,3."

I vote for the more modern "lens aperture," using the word "lens" as an adjective instead of a possessive noun. The Saxon genitive (lens') is disappearing in cases like this, but is still correct as well and I might prefer it for doctoral dissertations. However, I, like Struan, prefer "f-number" or "f-stop" when speaking of apertures since those terms are less ambiguous.

I have a tendency to use the terms "larger aperture" and "smaller aperture" as well at times, but often find myself stuck explaining that the larger aperture is the one with the smaller f-number, but not really, because the f-number is actually a fraction, so 1/5.6 is really larger than 1/22, so when I say use a smaller aperture than f/8 that means f/11, f/16, f/22... and so on. It seems hard to avoid this can of worms but at least you can tell someone to just look at the physical size of the aperture and larger is larger, smaller is smaller.

Rick; as for "where should I put the comma," vs. "where should I put the comma", you should use the former (since you are American). Those in the UK should use the latter (see the Chicago Manual of Style and compare it with the Oxford and Cambridge manuals).

Best

Doremus

[jcoldslabs]

"Len's aperture" makes me think of an orifice that opens and closes on the body of some guy named Len.

But if we're talking about "Frank's aperture" I have a few ideas as to what that could mean.

Jonathan

[Ian David]

It’s only a matter of time before someone recommends “lens’s aperture”

Here I am! Yep, you could write lens aperture, with no apostrophe at all (if used in the same sense as other compound nouns like bottle top, or kitchen table). Or you can refer to the lens's aperture. I don't think lens' aperture is correct in any context. Angst and hand-wringing can of course be avoided by referring to the aperture of the lens. If this stuff floats your boat, Fowlers Modern English Usage is pretty much the pedant's bible.

[Dan Fromm]

Frank, since you asked for my opinion or idea or whatever, I'll reply.

It seems to me that the best answer can be found with lens manufacturers. They haven't always used the same way of describing their lenses' [lens, singular, possessive, lens'; lenses, plural, possessive, lenses'; English is irregular, live with it] properties.

For, say, a 210/5.6 [as I'm used to expressing it], 210/5.6, F = 210 1:5.6, F 210 1:5.6, 1:5.6 F 210, Foyer 210 1:5.6, and 5.6/210 have all been used and all work.

There's no point wrangling about conventions without a higher authority that decrees which convention the world should use. I don't see such an authority.

As for correctness in language, well, there's a school of thought that holds that every utterance by a native speaker is correct. Live with it.

[Brian Ellis]

. . . When fully open, the aperture's diameter (in the case of your example) is 37.5mm, which is 210mm divided by 5.6.

I've sworn off correcting grammar when intent is clear, but, since you asked, Vaughn and polyglot got it right: "lens' aperture."

"Lens'" is the possessive plural. He was asking about useage when talking about a single lens so it's not "lens' aperture."

I don't think it's necessary to use an apostrophe at all, "lens aperture," meaning the aperture of the lens, is fine. But if one felt compelled to use the possessive it would be "len's aperture" when talking about a single lens.

[Dan Fromm]

Brian, most cameras have a lens, not a len. The rule I was taught in grammar school was that the possessive of a singular noun that ends in "s" is the noun plus an apostrophe. Lens, lens'.

As I said, English is very irregular.