Talk:Pinhole camera

message: "The f-stop of the camera may be calculated by dividing the diameter of the pinhole into the focal length of the camera"
The f-stop is the aperture, isn't it? shouldn't it say exposure time? Shouldn't it be "focal length"/"diameter"="exposure time"?
The f-stop is not just the aperture size, but rather the ratio between aperture size and focal length, if I remember right. 128.163.235.175 (talk)
== DOF clarif
The article states: The depth of field is basically infinite, but this does not mean everything will definitely be in focus. Depending on the distance from the aperture to the film plane, the infinite depth of field means everything is either in or out of focus to the same degree.
It's not clear to me why infinite depth of field doesn't put everything in focus.  The depth of field page did not help on this matter.  Maybe I'm dense, but perhaps this article could explain this non-intuitive concept a bit more explicitly, at least as it applies to pinholes. --Ds13 03:03, 21 April 2006 (UTC)
thread_title: Calculating the f-stop & required exposure

message: The external links section was far too big, especially for the size of the article. Several of the links seem to be providing the same info, just on different sites. I have put all the links below, so they can be hand-picked and put back into an external links section in the article. Even better, the information in them can be used to expand the article. That is where the information should be, not in an external link. Any links not required can be deleted from the list below. Please note: anyone connected with one of the sites below should not put it back into the links section. Tyrenius 01:09, 25 May 2006 (UTC)
thread_title:  External links 

message: This link seems broken.  Please could someone who knows a bit more about this area correct the link please?  I spotted this one:
http://www.legacyphotoproject.com/
which may be correct, but I'm not confident that this is the right link.
Labour Lawyer (talk) 13:28, 25 May 2009 (UTC)
thread_title: World's largest camera - link broken

message: I hadn't paid that close of attention to the introduction to this article, but the latest edit (The defect of pinholes are that the pictures come out in black and white if a CCD without color filters or a black and white film is used.) raises an interesting point: Isn't that like saying that "If you use black and white equipment, you'll get black and white photos"? To me, this doesn't seem like a defect but rather common sense. If I'm mistaken, please tell me. --Douglas Whitaker 17:54, 20 July 2006 (UTC)
replies: text: Deleted till clarified. Tyrenius 18:04, 20 July 2006 (UTC)
thread_title:  Black and White 

message: If I'm not mistaken, the positive should also be a mirror image of the negative and not just inverted colors. --Douglas Whitaker 20:49, 10 January 2007 (UTC)
replies: text: Best to make certain (find references) first. Tyrenius 23:51, 10 January 2007 (UTC)

text: The scene was photographed directly on photo paper. This gives a photo with inverted colours, but the image is not reversed. (A little confusing, but the lens projects a rotated image on the surface of the paper. Only when looking through the lens or through a transparency is the negative image reversed.) To get the positive image, the original photo is placed (image side up) on an enlarger directly on unexposed photo paper. Using a rather long exposure time, the (still not reversed) image is exposed to the photo paper through the negative photo to produce an image with positive colors. I hope I've explained myself clearly. --Matthew Clemente 15:47, 12 January 2007 (UTC)
replies: text: For example, take a standard 35mm negative. Looking at one side produces a negative-color image, but it is not reversed. Looking at the other side gives a reversed image. And the print is not reversed either (in this case because the negative is placed backwards in the enlarger and the lens then projects a reversed-reversed image). --Matthew Clemente 15:51, 12 January 2007 (UTC)
thread_title: Photo of Fire Hydrant

message: I think this section could use a citation.  The "Worldwide Pinhole Photography Day" home page at this URL http://www.pinholeday.org/ seems like a good source to use.  Anyone with more expertise on this area care to comment?  --Smiller933 21:46, 6 March 2007 (UTC)
replies: text: Citations always welcome. Do put one in. Tyrenius 00:53, 7 March 2007 (UTC)
thread_title:  Worldwide Pinhole Photography Day 

message: It doesn't seem to be a pinhole camera, but rather a sort of coronagraph. Haven't done the research to be certain, but it looks like the pinhole camera was an earlier design for the project. Sho Uemura 19:14, 15 May 2007 (UTC)
thread_title: New Worlds Imager

message: should this page be protected from vandalism? it seems it's getting hit. 71.196.48.107 01:41, 23 August 2007 (UTC)
thread_title: vandalism

message: I put this comment on Talk:Fisheye lens but thought it might be more appropriate here.
A generalized pinhole camera having different refractive indexes on either side of the pinhole can perform either a fisheye or telephoto lens function.
In this case, the radius from the center of the focal plane to any projected point is still R = f \times \tan \theta as with any pinhole camera, where f is the focal length and \theta is the angle from the viewing axis to the point to be projected. In the general case, however, \theta is a nonlinear function of the refractive indexes and the position of the point to be projected: \theta = \arcsin {\left( \frac{n_t}{n_f} \sin {\theta_t} \right)}, where n_t and n_f are the refractive indexes on the target and focal plane sides, respectively, and \theta_t is the angle from the viewing axis to the the point to be projected, assuming the pinhole is at the origin.
If n_t < n_f you have a wide-angle pinhole lens; if the difference is large enough it acts as a fisheye. If n_t > n_f you have a telephoto pinhole lens.  Only in the special case n_t = n_f do you get a "traditional" pinhole camera with distortion-free straight lines.
Of course, the chromatic aberration in such a camera would be terrible, but it's obvious that fisheye or telephoto effects can be accomplished with a pinhole, and it's easy to simulate such a camera in a computer without the aberration effects.
Is this too obscure, or is it worth mentioning this aspect of a pinhole camera? -Amatulić (talk) 00:04, 5 February 2008 (UTC)
thread_title: Fisheye or telephoto pinhole camera

message: How would the size and brightness of the image formed by a pinhole camera change if the camera were made longer.
please help me out on this.
thankx  —Preceding unsigned comment added by 77.31.19.75 (talk) 14:14, 21 June 2008 (UTC)
thread_title:  questions on pinhole cameras 

message: The example pinhole camera image "A photograph taken with a pinhole camera using an exposure time of 2 seconds" is extraordinarily murky and poor quality, and not at all representative of the photographs that competent operators can produce from a pinhole camera. Please consider replacing it with a better one.
Example images, for comparison with the one here, include:
http://www.flickr.com/groups/zeroimage/pool/
http://www.flickr.com/groups/pinholers/pool/
http://www.flickr.com/groups/pinholephotography/pool/  —Preceding unsigned comment added by 91.195.142.1 (talk) 13:51, 15 August 2008 (UTC)
thread_title:  Example image 

message: Reading the article it seems weird to say that "A pinhole camera is a camera in which the lens is replaced by an extremely small hole"
A pinhole camera doesn't replace a lens with an aperture. It is a camera without a lens, cameras with lenses have apertures. Reading the article it makes it seems like a pinhole camera was a development from a camera with a lens when it is in fact the other way around, the pinhole camera being one of the first kinds of cameras.
As such if no one disagrees within the time it takes me to drink this cup of tea and smoke a cigarette I propose to edit the article so it sounds less weird.
Very little gravitas indeed (talk) 18:16, 3 October 2008 (UTC)
thread_title:  Pinhole Camera a camera without a lens? 

message: Your article states that the ancient Greeks believed that light was emitted by the eyes. I can hardly imagine this. How would they have explained the lack of light without a source like the sun, torches, lamps or whatever?
::I don't think they did.  They believed that the eyes sent out some kind of visual rays, which were able to sense the objects of vision, but the objects did also need to be illuminated by a light source.109.150.75.67 (talk) 11:48, 30 April 2016 (UTC)
thread_title: Light emission

message: Under "Selection of pinhole size" there are some strange calculations where in one example for focal length inch is used and in the other example cm is used. In reference 14 and 15 there are links how the calculations are done. --83.85.49.156 (talk) 02:12, 14 July 2016 (UTC)
thread_title:  Strange calculation of pinhole size 

message: * Pinhole camera
* Camera obscura
* Solar_eclipse#Viewing
* Pinhole (optics)
* Pinhole camera model (Redirected from Pinhole projection)
* Magic lantern
Some readers come to WP seeking info about direct viewing of pinhole projected image, such as for eclipses. There are many related WP articles, perhaps most relevant Pinhole camera, but none that do a great job of discussing the subject. (Also, a good discussion might mention that with care and fiddling ordinary hand-held binoculars can do quite a good job of projecting a clear and sizable image onto a safe surface.)-71.174.177.142 (talk) 21:44, 21 August 2017 (UTC)
thread_title:  pinhole image projection direct viewing 

message: Is the ratio of the image distance to the object distance
m=v      
      u
m=hi
      h. Sarfo809 (talk) 21:28, 21 January 2019 (UTC)
thread_title:  Linear magnification 

message: The description of a scheme to rapidly put very small images on a cylinder ascribed to Edison seems unlikely to have used a pinhole camera. lenses were available, and speed is described as a problem.
Is the pinpoint size of the images being confused with a pinhole used to make them, and the material better placed on another page?  Midgley (talk) 23:28, 26 November 2022 (UTC)
thread_title:  Pinpoint=Pinhole??