Talk:Aperture

message: Anyone know whether this can be applied to eyes? When one is in a bright area, can they focus more deeply? Just wondering... -Jeshii 02:09, May 2, 2004 (UTC)
Yes, it can. Ever tried squinting to focus? That's using the same trick ;). DodgeK 19:22, 3 August 2005 (UTC)
replies: text: The eye is just a biological lens.  Though, it'd be nice to be able to upgrade eyes like I can with my SLR... Cburnett 19:57, August 3, 2005 (UTC)
Shouldn't the pupil be the aperture stop? The pupil controls amount of light, not the iris. MonketDLuffy (talk) 06:43, 4 August 2011 (UTC)
thread_title: Eyes

message: Where's antenna aperture, effective aperture, etc.? Ojw 13:38, 18 October 2005 (UTC)
thread_title: Not just photographic

message: There has been some reverting back and forth about stops and depth of field.  So I added the following (hidden) comment in the text:
:There is some confusion here. So let's be clear: Long depth of field occurs when the lens opening, and thus the stop, is small. However, a small opening equals a large f-stop number.
--Jeremy Butler 12:58, 27 February 2006 (UTC)
replies: text:  Agreed - and in addition : Stopping down means reducing the aperture = increasing the f-number (or is it the other way round? ;). Redbobblehat (talk) 15:32, 29 August 2008 (UTC)
thread_title:  depth of field 

message: This was posted on the SA Forums and has a couple criticisms of this article. Could an expert review these and fix the article as they see fit?
"Just out of curiosity, I decided to look at the first thing I could think of that I have a fair degree of confidence in my knowledge. So, I went to Wikipedia and searched for 'Aperture' (as it relates to Photography).
A criticism:
"Aperture is usually measured in f-numbers. A lens will have a set of "f-stops" that represent doublings in the amount of light let through the aperture."
This is not quite true. While it is true that the standard f-stop progression used in photography does represent doublings of light per step along the progression, very few (if any) modern cameras work at this imprecise a level of granularity. Pretty much all cameras work in either 1/3 stop or 1/2 stop steps. So, telling people that each number in the set represents a doubling will quite likely confuse someone not familiar with the concept. They will be led to believe that if they increase the aperture by 1 "step" on a camera, they are doubling the amount of light being let in, and on the majority of modern cameras, that is not the case.
In short, they are confusing two concepts: the standard f-stop progression, and the f-stop scale as it is represented on modern cameras and lenses.
While it may be trivial, it took me all of 1 minute to look and find something that looks true enough, but is wrong in a subtle and meaningful way that might easily mislead someone who was using Wikipedia to find out about a new subject.
This doesn't even address the fact that the rest of that particular section is poorly worded in ways that tend to make things sound more or less absolute than they really are.
"A very fast zoom lens will be constant f/2.8, which means the aperture will stay the same throughout the zoom range.".
There are two concepts at work here: the existence of constant maximum aperture zoom lenses, and an example of such a lens with a particular quality (speed). As worded, this is a confusing mess. Will a very fast zoom lens always be a constant f/2.8? Is it possible a fast zoom lens exists that is a constant f/2.5? Why not explain the difference between constant max aperture and variable max aperture first, and why they exist, and then give examples, instead of throwing out examples mixed with terminology that the examples use?
Again, small things, but this was the first article I pulled up. Do you really think this kind of thing is isolated, and that I just got lucky?"
--Liface 18:43, 9 May 2006 (UTC)
replies: text: I find the problem is pretty widespread, and I've been working on fixing such things, little by little; see my contributions to see what I mean.  It's a big job to turn lots of amateur articles into serious professional-looking encyclopedia articles, but I see steady progress in that direction.  Just jump in and help. Dicklyon 19:38, 9 May 2006 (UTC)
thread_title: Problems with Aperture article

message: There seems to be some confusion of terminology between different fields. In optics, an "aperture" is any opening through which the light passes. In an optical system, such as a camera lens, the edges of each lens element or its fixture is an "aperture". The aperture stop is a special aperture: the one aperture within the system that limits the size of the axial cone of rays that can pass through the system to form an image. Usage of the terms in other fields (such as photography) may vary, and the article needs to deal with both usages clearly and distinctly.--Srleffler 06:45, 10 May 2006 (UTC)
replies: text: Your changes so far are great, but it's unclear what more you are saying we need to do.  I'd disagree on one fine point:  I'd say the aperture stop is a special stop, not a special aperture.  I'll check some books... Dicklyon 14:46, 10 May 2006 (UTC)
replies: text: My best authoritative book here is Hardy and Perrin, 1932, The Principles of Optics, ch. 5 p. 68 "The Limitation of Rays by Apertures".  This chapter title is already somewhat inverted from how I conceptualize it, which is that the "stop" provides the limitation, the "aperture" being the open part.  But let's see what they say... First off "...the aperture of the system, which is determined by the diameters of the lenses and the stops that it contains"  sounds good to me; no circular use of aperture to define aperture.  "The theory of stops was first developed by Abbe, and it constitutes one of the most useful concepts in the theory of optical instruments".  So far so good.  Then "...element II is the stop or diaphragm that such a system normally contains"; sounds good -- a stop is a physical blocking element, usually a diaphragm, that is a thin structure supported around its edges, and with a hole in it.  "image-forming pencil (of rays)...in the image space...has a half-angle θ′".  and "It is clear from the figure that the value of θ is determined by the diameter of the diaphragm II, which is therefore called the aperture stop in the terminology developed by Abbe.  Later, "it is obvious that the rim of either lens I or lens III (or both) might become the aperture stop if the diameters of these were decreased sufficiently."  Now, he never says there are multiple apertures, or that an aperture is a hole, or that a lens diameter is an aperture; he only applies the term aperture or aperture stop to the whole system.  He goes on "In rare cases, two stops may be equally effective, ..." so now he has multiple stops, but still only one aperture.  And "The fact that stop II is the aperture stop..." makes it clear that an aperture stop is a type of a stop, not a type of an aperture.  And "The field stop is the real diaphragm of which the entrance window is an image" talks about another type of stop, not a type of aperture.  So, I think I'll reword the article as I noted above.  Citations supporting other points of view are of course welcome. Dicklyon 20:26, 19 May 2006 (UTC)
thread_title: Aperture and aperture stop

message: Well, thanks to a recent edit we now have the picture of the Glossographia Anglicana Nova quote right next to the quote itself, as text. This is not acceptable. Options:
#move the picture somewhere else in the article
#delete the picture
#delete the text quote (less desirable due to accessibility concerns.)
#nuke the whole history section but keep the picture.
I mention the last option because the history section is really just two huge quotes with little explanation or discussion of the history. While the quotes are interesting, this is not an effective presentation of the history of aperture, and may violate WP:NOT#Wikipedia is not an indiscriminate collection of information.--Srleffler 12:47, 27 October 2006 (UTC)
thread_title:  Glossographia Anglicana Nova 

message: bhphotovideo.com shows 58 lenses with aperture 6.3 at the tele end.  I admit that 5.6 is more common (about 230 hits), and I'll stop arguing about it, but my objection was to uncommented changes without mentioning a reason or a source. Dicklyon 16:04, 20 May 2007 (UTC)
replies: text: Okay, just next time try not to cite a source that is bias towards specific brands/lens mounts, and having f/6.3 as a max aperture would suck, AF is a pain and f/6.3 is the limit for most consumer SLR's AF systems (some pro bodies can AF as narrow as f/8); not to mention the amount of light needed. Ctrlfreak13 20:28, 20 May 2007 (UTC)
thread_title: Zoom aperture range

message: According to  p.49.
*Actual Aperture is the mean diameter of the actual aperture formed by the diaphragm opening (this is not necessarily circular). Ie it's the physical hole inside the aperture stop.
* Relative Aperture is represented by a number N (f-number), which is defined as the equivalent focal length of the lens divided by the diameter EN of the entrance pupil; N=f/EN.
*Effective Aperture (sometimes used erroneously to refer to the entrance pupil) properly refers to the relative aperture corrected for a lens that is not focussed at infinity. Redbobblehat (talk) 15:56, 29 August 2008 (UTC)
replies: text: Those seem like sensible definitions. I'm not sure they are used universally, however. In optical engineering, what he calls the "effective aperture" is typically called the "working f-number". (Relative aperture is the f-number.)--Srleffler (talk) 21:38, 29 August 2008 (UTC)
replies: text:  Nailing down synonyms seems like a good use of wikipedia! "Working f-number" is certainly less ambiguous than "effective aperture". Jacobson seems very keen to avoid confusing the "effective aperture" with "entrance pupil", which is contradictory to at least 3 out of the 4 uses of "effective aperture" in the current article. Perhaps entrance pupil and exit pupil should be added to this context/list of specific photography/optics aperture terminology, so that their differences and relationships can be explained explicitly ? Redbobblehat (talk) 12:33, 30 August 2008 (UTC)
thread_title:  Actual, Effective and Relative aperture 

message: This article needs to be rewritten to a beginning target audience, and another article written for advanced readers. One for a beginner who's trying to figure out how to read the numbers showing on their camera? One for an advanced photographer, astronomer, or physics student.
Article would benefit greatly from two or three simple diagrams showing a cutaway side view of lens elements.
Terminology is inconsistent. I.e., is it a "prime lens", "a fixed focal length lens", an "FFL" or a non-zoom lens? The article uses all four terms in a single sentence without actually ever explaining what what it is! In places the article reads "film" as focus of a lens, in another "film or image sensor". In another, it uses "image/film plane"! Make it clear at the beginning of the article that a lens can focus on film, an electronic sensor, the back of the eye, or even a wall. Then use the same term throughout the article. Using "professional lenses" when "expensive" or "specialty lenses" is meant is imprecise, and unhelpful.
There is considerable original research. My understanding is that most professional photographers now prefer zoom lenses in most shooting situations. Kubrick's lens in Barry Lyndon may have had the largest aperture 20 years ago, but is that still true? Citation? Piano non troppo (talk) 20:29, 15 October 2008 (UTC)
replies: text: These are nits, not major rewrite issues.  I'll take the tag off.  Feel free to work on or point out specific issues that still need attention. Dicklyon (talk) 01:02, 16 February 2009 (UTC)
thread_title: Article target audience

message: Have I got this right : the aperture area described in the article is the same as the area of the entrance pupil because it is 'reverse engineering' the f-number (as effective focal length/entrance pupil diameter) ? --Redbobblehat (talk) 20:14, 2 March 2009 (UTC)
replies: text: I think so. This article needs updating to either clarify that most of what it is talking about is actually the entrance pupil, or clarify that in some fields "aperture" is used to mean "entrance pupil". —Ben FrantzDale (talk) 14:05, 5 December 2011 (UTC)
thread_title:  Aperture area 

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thread_title:  External links modified 

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thread_title:  External links modified 

message: In this edit pair, the only edits by User:Stinen~enwiki, we got the odd concept of collimation into the lead of this article, way back in 2007.  Sorry I didn't notice sooner.  This is wrong, unsourced, and not summarizing what the article says, so I'm going to take it out.  There's a good notion there, but collimation does not describe it. Dicklyon (talk) 05:32, 13 September 2018 (UTC)
thread_title:  Collimated?