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12-03-2008, 10:17 AM   #106
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QuoteOriginally posted by audiobomber Quote
Photographers use this effect in selecting "portrait length" lenses. The most accurate portrait will be obtained with a normal lens. A wide angle lens will stretch a person's face in an unflattering manner, and a telephoto lens will flatten the face in a flattering manner.
QuoteOriginally posted by Marc Sabatella Quote
As I have said many times now, this is quite simply a myth. it's not about focal length, it's about distance to subject. Changing focal lenth has *no effect whatsoever* on perspective.
Audiobomber is coming from the point of view of maintaining a constant subject size in the frame. In that scenario a wide lens requires moving closer to the subject, changing the perspective, and vice versa.

You're both right, just from differenct "perspectives".

12-03-2008, 10:41 AM   #107
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QuoteOriginally posted by Sean Nelson Quote
Audiobomber is coming from the point of view of maintaining a constant subject size in the frame. In that scenario a wide lens requires moving closer to the subject, changing the perspective, and vice versa.

You're both right, just from differenct "perspectives".
I believe the statements are contradictory. Subject size is only relevant in its relation to the size of the other items in the image.

A wide angle lens creates perspective distortion, a normal lens doesn't. A wide angle lens changes the relative sizes of the subject and the background. That's perspective distortion, and it is not "normal".
12-03-2008, 10:49 AM   #108
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QuoteOriginally posted by Sean Nelson Quote
Audiobomber is coming from the point of view of maintaining a constant subject size in the frame. In that scenario a wide lens requires moving closer to the subject, changing the perspective, and vice versa.

You're both right, just from differenct "perspectives".
No. "A wide angle lens will stretch a person's face in an unflattering manner, and a telephoto lens will flatten the face in a flattering manner." is simply an inaccurate statement. It's all about distance to subject. "Accurate portrait" doesn't exist. It's a choice of the photographer.
12-03-2008, 10:49 AM   #109
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QuoteOriginally posted by audiobomber Quote
I believe the statements are contradictory. Subject size is only relevant in its relation to the size of the other items in the image.

A wide angle lens creates perspective distortion, a normal lens doesn't. A wide angle lens changes the relative sizes of the subject and the background. That's perspective distortion, and it is not "normal".
"Normal perspective" does not exist.

12-03-2008, 11:11 AM   #110
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QuoteOriginally posted by Tokina Quote
No. "A wide angle lens will stretch a person's face in an unflattering manner, and a telephoto lens will flatten the face in a flattering manner." is simply an inaccurate statement. It's all about distance to subject. "Accurate portrait" doesn't exist. It's a choice of the photographer.
Honestly I think you guys have a point and it's true that many people don't understand that fact.

But, there is another side to it - think of a photographer who only takes pictures of people's faces, and the person's face always fills the frame. In a practical sense, to that photographer, the change in subject distance is not a parameter! It is not an option! For such a photographer, each focal length has an associated subject distance, and therefore an associated perspective.

Stop being so objective! Thinking subjectively is perfectly valid.

Best regards...
12-03-2008, 11:17 AM   #111
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QuoteOriginally posted by Michael Barkowski Quote
And then adjust your 50mm by the 0.85x magnification of the viewfinder and you get 42mm ... which is still quite long ... interesting experiment though.
? Is that what it is for the K100D/K200D? I have the K10D which is 95% viewfinder coverage. I was going to make a statement about that differential but didn't want to "muddy the waters".

To address some of the other points made to no particular one person, yes, it's the relation of closer objects to further away objects -- in how their relational sizes are "seen" thru the lens and affected by perspective from the lens's focal length being "wider" or "longer" than [ahem] "normal" -- that viewing a chair at an isometric angle is supposed to capture. Any significantly sized object relatively close to you can be the subject, or two objects with some space between them (isometric angle then not necessary). If you view say a [one] short candle however, the effect won't be very noticeable if at all. One can do the same by snapping an eye-piece that has 1x magnification (I only have a 3x eye-piece) to the back of a zoom and zooming in & out with one eye while keeping the other naked eye on the same subject if one feels better about removing the camera's mirror box from the whole equation.

I just don't get the whole debate of "what is the normals focal length that gives a perspective the same as the naked eye to all objects in both the foreground & background" when this effect of focal length can so easily be observed and truth be told by this method. In short to answer the OP of " A Fast Fifty Is Really A Fast 75mm", Answer: Yes as far as crop & what fits in the frame; No as far as perspective as a 50mm lens still projecting the same subject perspective onto the material reacting to the light and turning it into an image; when using digital, you just see less of that projected image because of the smaller sensor when compared to 35mm film... which is where the ##mm nomenclature comes from.

Last edited by m8o; 12-03-2008 at 11:33 AM.
12-03-2008, 11:19 AM   #112
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QuoteOriginally posted by Marc Sabatella Quote
Take pictures of a person using your favorite wide angle (well, not a fisheye) lens and your favorite telephoto lens, *without* changing your position. Now crop the image from the wide angle lens to give the sme FOV as the telephoto. There will be *no difference whatsoever* in the perspective of the two pictures.
I disagree. The relation of the nose to the back of the head will change very slightly, but probably not enough to notice under those conditions. That's not the way to show perspective distortion.

Take a photo a subject in front of and to the side of a landscape using your widest angle lens. Let's say the subject is the hood ornament on your new SUV and the background is a mountain. Take the same shot from the same position using a normal lens and then your longest telephoto lens. Now print all of them (or display at the same size on your monitor). Measure the size of the foreground ornament and the size of the distant mountain. The ratio of the sizes will change based on focal length. The mountain will look smaller in proportion to the car in the wide angle lens than it will in the telephoto lens. With the normal lens the relative size of the car will remain in proportion to the relative size of the mountain. In other words, the image will be in exactly the same proportion as you saw in the scene with your eye. The wide and telephoto images will exhibit perspective distortion in relation to your normal eyesight.

Last edited by audiobomber; 12-03-2008 at 11:40 AM.
12-03-2008, 11:30 AM   #113
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QuoteOriginally posted by Michael Barkowski Quote
Honestly I think you guys have a point and it's true that many people don't understand that fact.

But, there is another side to it - think of a photographer who only takes pictures of people's faces, and the person's face always fills the frame. In a practical sense, to that photographer, the change in subject distance is not a parameter! It is not an option! For such a photographer, each focal length has an associated subject distance, and therefore an associated perspective.

Stop being so objective! Thinking subjectively is perfectly valid.

Best regards...

Yeah. If i'm going to take portraits I will most likely use focal lengths 50-90mm (crop sensor). That gives the right working distance (perspective) for conventional portraits.

12-03-2008, 11:44 AM   #114
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QuoteOriginally posted by Michael Barkowski Quote
But, there is another side to it - think of a photographer who only takes pictures of people's faces, and the person's face always fills the frame. In a practical sense, to that photographer, the change in subject distance is not a parameter! It is not an option! For such a photographer, each focal length has an associated subject distance, and therefore an associated perspective.
Like this. The WA is weird, the 50mm is the most accurate, the telephotos are most flattering. Untitled Document

Last edited by audiobomber; 12-03-2008 at 11:50 AM.
12-03-2008, 11:45 AM   #115
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QuoteOriginally posted by audiobomber Quote
I disagree. The relation of the nose to the back of the head will change very slightly, but probably not enough to notice under those conditions. That's not the way to show perspective distortion.

Take a photo a subject in front of and to the side of a landscape using your widest angle lens. Let's say the subject is the hood ornament on your new SUV and the background is a mountain. Take the same shot from the same position using a normal lens and then your longest telephoto lens. Now print all of them (or display at the same size on your monitor). Measure the size of the foreground ornament and the size of the distant mountain. The ratio of the sizes will change based on focal length. The mountain will look smaller in proportion to the car in the wide angle lens than it will in the telephoto lens. With the normal lens the relative size of the car will remain in proportion to the relative size of the mountain. In other words, the image will be in exactly the same proportion as you saw in the scene with your eye. The wide and telephoto images will exhibit perspective distortion in relation to your normal eyesight.
I think you should do that test yourself. Ratios in pictures don't change if taken from the same spot.
12-03-2008, 11:49 AM   #116
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QuoteOriginally posted by m8o Quote
? Is that what it is for the K100D/K200D? I have the K10D which is 95% viewfinder coverage. I was going to make a statement about that differential but didn't want to "muddy the waters".
I was talking about magnification, and I think that's what you meant as well...
Coverage isn't relevant if you're talking about subject size, but yes I believe K10D is 0.95 magnification, 95% coverage, while my K100D is 0.85x magnification, 96% coverage. I'm taking the values from a helpful chart here:
Standard versus Enhanced Viewfinders - Size Matters :: Wetpixel.com
12-03-2008, 11:54 AM   #117
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QuoteOriginally posted by audiobomber Quote
Like this. The WA is weird, the 50mm is the most accurate, the telephotos are most flattering. Untitled Document
Yes, exactly. Although the linked page is not very scientific, in that it kind of exaggerates it with different lighting (look at the reflected light on the right side of the nose - it's not there in every shot), and expression/pose (the left-right angle of the head is obviously different in some of them).

So the statement "A wide angle lens will stretch a person's face in an unflattering manner, and a telephoto lens will flatten the face in a flattering manner." is not "simply inaccurate", although the statement makes unspoken assumptions and is therefore subjective.

P.S. I don't think the exaggeration was intended. I think the lighting setup stayed fixed, but the model unconsciously changed her expression and head angle. For example, her eyes started to close - a defense mechanism.

Last edited by Michael Barker; 12-03-2008 at 12:02 PM.
12-03-2008, 11:54 AM   #118
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QuoteOriginally posted by audiobomber Quote
Like this. The WA is weird, the 50mm is the most accurate, the telephotos are most flattering. Untitled Document
No... that may be your opinion but the beauty is in the eye of the beholder. Just like perspective always is


Additional question: Do you like to watch your wife from far away with binoculars? Or from "accurate distance"

Last edited by Tokina; 12-03-2008 at 12:14 PM.
12-03-2008, 12:08 PM   #119
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QuoteOriginally posted by Tokina Quote
No... that may be your opinion but the beauty is in the eye of the beholder. Just like perspective always is
Now at least you're being subjective
12-03-2008, 12:16 PM   #120
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QuoteOriginally posted by Tokina Quote
No... that may be your opinion but the beauty is in the eye of the beholder.
That's true.

QuoteOriginally posted by Tokina Quote
Just like perspective always is
That's incorrect. Perspective is very real and has been understood in art for millenia. You're not a very thoughtful person are you Tokina? Why don't you do some research instead of this one-line sniping?

I will do the measurement test I proposed when I have time.
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