Perspective (was Re: Has ultrawide angle become an overused cliche?)
in [Digital Cameras]
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From: Neil Harrington on 9 Aug 2010 13:09 "Bruce" <docnews2011(a)gmail.com> wrote in message news:0bhv56t3lbo6bk0ktoj56cj7tjf6phdpuh(a)4ax.com... > On Mon, 9 Aug 2010 01:27:40 +0000 (UTC), "Mike Warren" > <miwa-not-this-bit(a)or-this-csas.net.au> wrote: >>I just performed a simple resize of the second image and laid it on >>top of the first: >> >>http://www.mike-warren.net/play/savageduck.jpg >> >>Perspective is unchanged. > > > > Exactly right. You are someone who understands perspective. > > All the wide angle lens does is include more in the shot. Of course > that is precisely why it is called a "wide angle" lens. To "include more in the shot" (by using a wider angle lens) changes the perspective. It cannot help but do so, assuming that the subject is sufficiently three-dimensional to provide perspective at all. (A flat subject perpendicular to the lens axis has no perspective.)
From: Neil Harrington on 9 Aug 2010 13:11 "Shiva Das" <shiv(a)nataraja.invalid> wrote in message news:shiv-BDD52B.12332709082010(a)reserved-multicast-range-NOT-delegated.example.com... > In article <2010080817520211272-savageduck1(a)REMOVESPAMmecom>, > Savageduck <savageduck1@{REMOVESPAM}me.com> wrote: > >> On 2010-08-08 16:37:50 -0700, Bruce <docnews2011(a)gmail.com> said: >> >> > On Sun, 8 Aug 2010 16:43:55 -0400, "Neil Harrington" >> > <nobody(a)homehere.net> wrote: >> >> "Bruce" <docnews2011(a)gmail.com> wrote in message >> >> news:ugar46dfhpou4nimibd86jm53iqo459f99(a)4ax.com... >> >>> On Mon, 26 Jul 2010 09:54:10 -0400, Shiva Das <shiv(a)nataraja.invalid> >> >>> wrote: >> >>>> In article <5k2r46pe2t2t7tsjn802pa3o5v7lla946f(a)4ax.com>, >> >>>> Bruce <docnews2011(a)gmail.com> wrote: >> >>>>> It also doesn't help when people associate perspective with the >> >>>>> lens's >> >>>>> focal length. Perspective is purely a function of viewpoint and >> >>>>> its >> >>>>> relationship with the subject. The focal length of the lens is >> >>>>> irrelevant. >> >>>> >> >>>> In "Photographic Lenses: Photographer's Guide to Characteristics, >> >>>> Quality, Use and Design" Ernst Wildi has two sets of photographs >> >>>> using >> >>>> progressively longer lenses from 38mm to 500mm Hasselblad lenses >> >>>> (20mm >> >>>> to 255mm equivalentin 35mm film format). >> >>>> >> >>>> The first sequence, one shot per lens, is taken standing in the same >> >>>> spot looking at the same scene. The second sequence is of a lovely >> >>>> lady >> >>>> on the beach and he moved the camera to keep her the same size in >> >>>> each >> >>>> image. >> >>>> >> >>>> It does a great job of showing how focal length and distance affect >> >>>> perspective. >> >>> >> >>> >> >>> Yes, that is the classic method of demonstrating that perspective is >> >>> independent of focal length. >> >>> >> >>> It is to be found in many books on photography, yet people still keep >> >>> making the same mistake over and over again, thinking that >> >>> perspective >> >>> is dependent on focal length. >> >> >> >> But perspective *is* largely dependent on focal length. >> >> >> >> The the other poster mentioned ". . . how focal length and distance >> >> affect >> >> perspective." >> >> >> >> Focal length is not "irrelevant." Both are important: focal length >> >> *and* >> >> camera position. A shot taken with a wide-angle lens has wide-angle >> >> perspective, which (assuming there are enough objects arranged in the >> >> scene >> >> to establish perspective at all) is easily recognized by anyone >> >> looking at >> >> the resulting photo. To say that focal length is irrelevant is to deny >> >> what >> >> anyone can see with his own eyes. >> >> >> >> (Sorry for being more than a week late in replying to this, but I only >> >> saw >> >> the thread just now. The misunderstanding is important enough to >> >> correct. >> >> The "many books" that support the idea are mistaken, as are the >> >> several >> >> people who have repeated it over the years.) >> > >> > >> > The "misunderstanding" is entirely yours, Neil. It is a very common >> > misunderstanding. However, it doesn't matter how many people repeat >> > it, nor how many times, it is still wrong. There is no such thing as >> > "wide angle perspective". >> > >> > Perspective is purely a function of viewpoint and its relationship >> > with the subject. The focal length of the lens is irrelevant. >> > >> >> OK. >> I tried the following; >> D300s on tripod 2 shots, position of tripod unchanged, aim point >> unchanged, distance between camera and subject constant, lenses >> changed, EXIF included; >> >> Shot #1 Tokina 11-16mm f/2.8 @ 11mm (16mm FF equiv.) >> < http://homepage.mac.com/lco/filechute/_DNC3876w.jpg > >> >> Shot #2 Nikkor 16-200mm VRII @ 35mm (52mm FF equiv.) >> < http://homepage.mac.com/lco/filechute/_DNC3877w.jpg > >> >> Side by-side comparison; >> < http://homepage.mac.com/lco/filechute/Merc-comp-01.jpg > >> >> It is tough to say that that this is not a demonstration of focal >> length perspective change. >> The view point is constant, the relationship between the subject (the >> car) and the camera remains unchanged. Yet the eye tells the viewer >> there is a dramatic change in perspective, in this case created >> entirely by a change of focal length. > > Nope. > > <http://www.flickr.com/photos/52865695(a)N03/4875633691/> > > All I did was crop the 11mm photo to the same field of view as the 35mm > photo. There is absolutely no difference in the perspective. Cropping the photo changes its perspective.
From: Neil Harrington on 9 Aug 2010 13:34 "Savageduck" <savageduck1@{REMOVESPAM}me.com> wrote in message news:2010080909524211272-savageduck1(a)REMOVESPAMmecom... > On 2010-08-09 09:35:53 -0700, "Neil Harrington" <nobody(a)homehere.net> > said: > >> >> "David J Taylor" <david-taylor(a)blueyonder.co.uk.invalid> wrote in message >> news:i3o7b5$4p5$1(a)news.eternal-september.org... >>> "Savageduck" <savageduck1@{REMOVESPAM}me.com> wrote in message >>> [] >>>> Damn! I should have thought of doing that. >>>> >>>> So it seems the eye is easily fooled by focal length changes. Thanks >>>> for >>>> the proof you provided, I kind of takes the wind out of my sails, but >>>> there it is. >>>> >>>> >>>> -- >>>> Regards, >>>> >>>> Savageduck >>> >>> But you are correct that the resulting image /looks/ different, although >>> the change is not because of a perspective change as such, but because >>> of >>> a field of view change. I.e. a narrow-angle shot looks different to a >>> wide angle shot, perhaps because of the amount of included material and >>> the context of a part of the image compared to the rest of the image. >> >> Those differences establish a difference in perspective. The term "wide >> angle perspective" is correct -- how else would you describe *how* you >> can >> easily tell a wide angle shot from a normal or longer lens shot? > > Neil, I was on your side of this argument when I took those shots. I was > trying to prove your point using the argument that you used, and thought I > had. And indeed you had. > However Mike proved to me, using my own shots that the perspective > remained unchanged with the change in FL when the camera/subject position > is constant. Certainly the wide angle "view" is different to the normal, > or long lens "view", but the perspective remains the same. I had the idea > that because the shots looked different the perspective had changed, I was > wrong. No, you were right. That's what perspective *is*, the visible difference in object relationships in a three-dimensional world. When you subtract part of a scene, it is easy (and sometimes unavoidable) to change the perspective. > > What you are calling a "wide angle perspective" is actually a "wide angle > view". If you had obtained the same change of "view" with a 50mm prime, by > moving the camera away from the subject, there should have been a change > in perspective along with the change in view. Yes indeed. As I said in my initial reply to Bruce in this sub-thread: >>> Focal length is not "irrelevant." Both are important: focal length *and* camera position. <<< Changing either one changes perspective, assuming enough three-dimensional object(s) in the scene to provide perspective. Only if you consider perspective to apply SOLELY to some small central portion of the picture does the perspective remain unchanged with focal length changes. Your wide-angle shot (in your experiment) provides wide-angle perspective. You can see it. I can see it. Bruce can see it. I'll bet anyone can see it. It is only through perspective that you, Bruce, I and all those other people can tell it was taken with a wide-angle lens. The now-popular (for whatever reason) fallacy that perspective is completely independent of focal length requires that believers deny the evidence of their own eyes.
From: David J Taylor on 9 Aug 2010 13:46 "Savageduck" <savageduck1@{REMOVESPAM}me.com> wrote in message news:2010080909524211272-savageduck1(a)REMOVESPAMmecom... [] > What you are calling a "wide angle perspective" is actually a "wide > angle view". If you had obtained the same change of "view" with a 50mm > prime, by moving the camera away from the subject, there should have > been a change in perspective along with the change in view. > > -- > Regards, > > Savageduck That's an excellent term, thank you. David
From: Savageduck on 9 Aug 2010 13:54
On 2010-08-09 10:04:14 -0700, "Neil Harrington" <nobody(a)homehere.net> said: > > "Savageduck" <savageduck1@{REMOVESPAM}me.com> wrote in message > news:2010080908280775249-savageduck1(a)REMOVESPAMmecom... >> On 2010-08-09 06:22:13 -0700, bugbear <bugbear(a)trim_papermule.co.uk_trim> >> said: >> >>> Savageduck wrote: >>>>> >>>>> I just performed a simple resize of the second image and laid it on >>>>> top of the first: >>>>> >>>>> http://www.mike-warren.net/play/savageduck.jpg >>>>> >>>>> Perspective is unchanged. >>>> >>>> Damn! I should have thought of doing that. >>>> >>>> So it seems the eye is easily fooled by focal length changes. Thanks for >>>> the proof you provided, It kind of takes the wind out of my sails, but >>>> there it is. >>> >>> Here's all of the above, all mixed up >>> >>> http://en.wikipedia.org/wiki/Dolly_zoom >>> >>> BugBear >> >> >> That really does mess with perspective due to the changing camera/subject >> distance. >> Now that would really have been a problem for me since my idea was to keep >> the camera/subject distance constant to see if there is a perspective >> change due to focal length change. > > And there was. > >> ...and my own shots have proved to me that there is no perspective change >> due to focal length change. > > No, what was proved to you was "that there is no perspective change" OF THAT > SMALL PART OF THE PICTURE. How could there be? > > Look at it this way: Suppose you just used one zoom lens and changed from > its shortest focal length to its longest, changing nothing else. At the > shortest f.l. (assuming a wide-to-tele zoom) the picture would have the > familiar wide-angle perspective. As you zoomed in, you would just be > progressively magnifying the central part of the picture -- so the > perspective OF THAT PART could not possibly change. > > That is essentially the same thing Mike's resizing part of your second photo > has done. > > Again: perspective is something that involves the entire picture. That is > why the various "proofs" that perspective depends solely on camera position > are fallacious -- all such "proofs" that I have seen involve using smaller > parts of the picture which have their own, different perspective. I think the problem is we each have our own interpretation, or misinterpretation of "perspective" and/or view. I have always thought of change of perspective to be relative to position of view point or camera. For example using the classic vanishing point lines of convergence an artist might use, the perspective remains constant at all points between those converging lines. That is effectively what happens with a zoom lens changing FL. Move the camera, or view point laterally and there is a change in perspective. Taking shot down a set of parallel railroad tracks will show a converging vanishing point. Change the FL of that shot, and the vanishing point remains the same, but the view has changed. Now move the camera laterally and the perspective can be changed until all that is seen is the side of a single rail. All very interesting, and thought provoking. Like you, I also find it difficult to deny the thought that a change of FL such as the one I made does not result in a change in perspective. -- Regards, Savageduck |