Re: [pinhole-discussion] wideangle, telephoto, etc
This of it this way: If you have a slide projector shining a slide of, say, your family, up on a wall. You are seated between the projector and the wall. If you hold your hand up, between the projector, and the wall, obviously you see some of the image on your hand. As you move your hand away from the projector, only a tiny part of the scene is reflected on your hand- say, only the face of your uncle Mortimer. This is analagous to a long focal length, with the subject "zoomed" in (on just your uncle's face). Now, walk toward the projector, with your hand up. More and more of the scene is reflected on your hand as you decrease the distance to the projector. Eventually, you hand is only a few inches away from the projector. What do you see projected on your hand? The entire picture of your family. You have "zoomed out" to wide angle by decreasing the distance. This is pretty much what is happening in your pinhole camera, only the pinhole itself is the "projector", shining the scene on the film plane. If we change the distance of the film plane from the pinhole ( focal length), we either zoom or zoom out the scene. Hope this helps... On Thu, 9 Aug 2001, Murray wrote: > Hello: > > In the case of pinhole photography, the titles 'wide angle' or 'telephoto' > would only refer to the field of view, right? There's nothing to provide > magnification. > > My brain wants to associate the term telephoto with a zoom telephoto > lens...I think of "tele- anything" as meaning "at a distance"... > telekinetic = motion without contact, telephone = sound transported > technologically from a distance, television = visual image transported from > a distance. > > So, if one were to change pinhole and focal length (say there were a bellows > or telescoping camera chamber), and shoot the same scene from the same > camera position, would just the field of view change, or would the image > size from the telephoto be 'closer' or larger than that of the wide angle > configuration? > > Thanks for all replies > > Murray > > > ___ > Pinhole-Discussion mailing list > Pinhole-Discussion@p at ??? > unsubscribe or change your account at > http://www.???/discussion/ >
Re: [pinhole-discussion] wideangle, telephoto, etc
The acceptance angle or field of view at any pinhole-film distance is a function of the width of the negative. The optimal image is the shape of a hemisphere centered around the pinhole. Whether you have "closer up" or "further away" depends on how much of the potential image is covred by the negative. - Original Message - From: Murray To: Sent: Thursday, August 09, 2001 5:15 PM Subject: [pinhole-discussion] wideangle, telephoto, etc > Hello: > > In the case of pinhole photography, the titles 'wide angle' or 'telephoto' > would only refer to the field of view, right? There's nothing to provide > magnification. > > My brain wants to associate the term telephoto with a zoom telephoto > lens...I think of "tele- anything" as meaning "at a distance"... > telekinetic = motion without contact, telephone = sound transported > technologically from a distance, television = visual image transported from > a distance. > > So, if one were to change pinhole and focal length (say there were a bellows > or telescoping camera chamber), and shoot the same scene from the same > camera position, would just the field of view change, or would the image > size from the telephoto be 'closer' or larger than that of the wide angle > configuration? > > Thanks for all replies > > Murray > > > ___ > Pinhole-Discussion mailing list > Pinhole-Discussion@p at ??? > unsubscribe or change your account at > http://www.???/discussion/ >
Re: [pinhole-discussion] wideangle, telephoto, etc
- Original Message - From: "Murray" > In the case of pinhole photography, the titles 'wide angle' or 'telephoto' > would only refer to the field of view, right? The same is for glass lenses. > There's nothing to provide magnification. Not sure I understand that statement. In the way you (I think) use the term magnification, both a pinhole and a glass lens would "provide" magnification provided the object/subject of your picture is at 1 focal length distance or 2 focal length distance (respectively) from the camera. > So, if one were to change pinhole and focal length (say there were a bellows > or telescoping camera chamber), and shoot the same scene from the same > camera position, would just the field of view change, or would the image > size from the telephoto be 'closer' or larger than that of the wide angle > configuration? Both, the field of view changes and also the object, when using a "telephoto" set up will be larger with respect to a "wide angle" set up. But what it will not change is the PERSPECTIVE. That is why you could reduce the telephoto image in such way that the whole image blends perfectly with the wide angle image (object/subject sizes wise). Again, a glass lens works in the same manner, too. Guillermo
[pinhole-discussion] wideangle, telephoto, etc
Hello: In the case of pinhole photography, the titles 'wide angle' or 'telephoto' would only refer to the field of view, right? There's nothing to provide magnification. My brain wants to associate the term telephoto with a zoom telephoto lens...I think of "tele- anything" as meaning "at a distance"... telekinetic = motion without contact, telephone = sound transported technologically from a distance, television = visual image transported from a distance. So, if one were to change pinhole and focal length (say there were a bellows or telescoping camera chamber), and shoot the same scene from the same camera position, would just the field of view change, or would the image size from the telephoto be 'closer' or larger than that of the wide angle configuration? Thanks for all replies Murray
