Perspective (was Re: Has ultrawide angle become an overused cliche?)
in [Digital Cameras]
|
From: David Ruether on 9 Aug 2010 12:43 "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. > > Cheers, > David This shows that there actually *is* another ingredient to the conditions-list, the specification of sensor size relative to FL, which then gives angle of view and an indication of what the perspective "look" might be. As I pointed out before, a 10mm lens (for instance) can be a super-wide on one format (with its notable perspective effects), and even a tele on another format with a much smaller sensor. So, viewpoint, lens FL, lens/sensor perspective type, sensor size, and the aperture used (assuming a motionless camera and good exposure) combine to help predict the appearance of a photo (with a given set of visual materials out there in front of the camera...;-). --DR
From: Savageduck on 9 Aug 2010 12:52 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. 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. 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
From: David Ruether on 9 Aug 2010 12:57 "Savageduck" <savageduck1@{REMOVESPAM}me.com> wrote in message news:201008090937098930-savageduck1(a)REMOVESPAMmecom... > On 2010-08-09 09:05:28 -0700, "David Ruether" <d_ruether(a)thotmail.com> said: >> "Savageduck" <savageduck1@{REMOVESPAM}me.com> wrote in message >> news:2010080818434227544-savageduck1(a)REMOVESPAMmecom... >> This shows that there actually *is* one more ingredient to the >> conditions-list, the specification of sensor size relative to FL, >> which then gives angle of view and an indication of what >> perspective "look" might be expected. As I pointed out before, >> a 10mm lens (for instance) can be a super-wide on one format, >> and a tele on another format with a much smaller sensor... >> --DR > Not really. What I did does not demonstrate anything relative to sensor size. > I did not change cameras, I changed lenses in an attempt to show a change in FL would change perspective. I noted the FF > equivalent FL. > Mike Warren demonstrated above, with my own shots that I was wrong. > Here are those shots again. > 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 > > > and Mike's demonstration of unchanged perspective using those shots. > < http://www.mike-warren.net/play/savageduck.jpg > > > -- > Regards, > > Savageduck Yes - these prove what I pointed out, above. If you maintain a constant "subject"/lens distance, and the same perspective lens *type* is used for two photos, enlarging (or reducing) the sensor size will change the angle of view covered in the photo, and thus its appearance. All of the above shows this. It is true that the perspective does not change, but increasing the sensor size *can* include a wider angle of view, and thus likely more WA "perspective effects", unless the subject is a straight-on flat surface that is parallel with the sensor... --DR
From: Savageduck on 9 Aug 2010 13:02 On 2010-08-09 09:33:32 -0700, Shiva Das <shiv(a)nataraja.invalid> said: > 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. I have already admitted my faulty argument after Mike Warren demonstrated the same thing you did by resizing the 35mm shot and placing it as an overlay on the 11mm shot. < http://www.mike-warren.net/play/savageduck.jpg > I stand educated, lesson learned. -- Regards, Savageduck
From: Neil Harrington on 9 Aug 2010 13:04
"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. |