Is Zooming the same as getting closer?

[Steve H]

Certainly demonstrates that the two extremes of focal length/subject distance give completely different images. Well done.

Steve H
--

 

[gwprovost]

In the movies they call that a smash-zoom, or push-pull-zoom. There are good examples in Spielberg's 'Jaws' (Brody on the beach), Scorcese's 'Goodfellas' (Henry in the diner), and in Hitchcock's 'Vertigo' (Scottie in the bell tower).

Thanks for your contibution to understanding

 

[amtberg]

Thanks guys, glad you liked it.

Just to complete the set, here's a few more demonstrating the effect of zooming without moving and moving without zooming:

http://www.3danvil.com/ZoomEffect_moveonly.html
http://www.3danvil.com/ZoomEffect_moveonly_editor.html

So, moving closer/farther has a marked effect on perspective, and

http://www.3danvil.com/ZoomOnly.html
http://www.3danvil.com/ZoomOnly_editor.html

Zooming without moving has no effect on perspective.

 

[Gautam Majumdar]

--
Gautam

 

[PhotoTom]

I think a lot of the confusion comes from books that change both at the same time, thus giving the illusion that focal length change affects perspective and vica-versa. One of the texts I remember reading showed different focal lengths in a series of images, but also moved the camera to accomodate equivalent framing with each lens. The text described it nicely, but the caption under each image only gave the focal length, leading a skimming reader to assume that the focal length was the only thing that changed.

--
Tom

 

[kwik67]

I remember universal studios tour (California) had this as one exhibit to demonstrate how the vertigo shoot was performed.

--
http://rdphotog.smugmug.com

 

[gdgeisler]

I get it now, there is no substitute for actually moving if you want to change in perspective. Zooming is simply cropping, the advantage being simply more pixels and nothing else (assuming a perfect zoom lens)
Gerry

 

[Lee Jay]

I get it now, there is no substitute for actually moving if you
want to change in perspective. Zooming is simply cropping, the
advantage being simply more pixels and nothing else (assuming a
perfect zoom lens)

Pretty much right. There is a depth-of-field issue too.

--
Lee Jay
(see profile for equipment)

 

[Lee Jay]

You can get a different perspective without moving. See if you can figure this one out:



--
Lee Jay
(see profile for equipment)

 

[PhotoTom]

You can get a different perspective without moving. See if you
can figure this one out:

--
Lee Jay
(see profile for equipment)

I dunno - give me time to reflect.
--
Tom

 

[Lee Jay]

I dunno - give me time to reflect.

Reflect some more. ;-) That shot has an AOV of around 90 degrees and was shot with the 100/2 on the 20D. The effective location of the shot was on the other side of an opaque wall.

--
Lee Jay
(see profile for equipment)

 

[gdgeisler]

If I want to capture what you "see" then what type of lens?

In theory you see the equivalent of what a 50mm lens sees (FF), but effectively your mind will often isolate an image (zoom in). That said if you want a lens that mimimics "how you see" you would want a 50mm- ? mm Zoom on a FF (31.6mm-? APS). So on an APS camera the 24-105L (38.4-168 ff equivalent) should do nicely.

Gerry

 

[Lee Jay]

If I want to capture what you "see" then what type of lens?

There is no direct answer to this question without out including the final print/projection size/format.

--
Lee Jay
(see profile for equipment)

 

[gdgeisler]

This discussion has dealt primarily with the "physics" of optics but no one has discussed "how" human beings actually "see" (perceive).

I believe the erroneous comment that "perspective is flattened" by using a longer focal lenght comes from the assumption that we, as human beings, always "see" with our full field of view. Thus if you Zoom in a subject so that it fills the cameras feild of view, if that was indeed how we saw the image in real life, the cameras image would indeed be "flattened". In other words to actually fill our visual feild of view we would have needed to walk up to the subject, and thus there "should" be a different perspective.

In reality, we probably seldom actually pychologically "see" what is in our full field of view. We are always "zooming" in objects of interest. Most of the time we "crop" what is uninteresting, we don't walk up to what is intersting. It is for this reason that Zooming in with a camera lens can be perceived as perfectly natural since in mimics what our mind does, not what the lens in our eye does.

 

[DavidMaven]

Zooming changes only the magnification of the image.

Moving the camera relative to the subject changes the perspective. What people consider a change in perspective from only a change in focal lenght is NOT perspective change, pure and simple.

Vocabulary-challenged photographers sometimes call it "apparent perspective" or "compression". But changing focal length from fixed position while enlarging/reducing to keep constant image size on output medium proves that focal length it is only a magnification change, not a perspective change

That is why knowledgable photography instructors tell their students to avoid relying on zoom lens; they tell them to MOVE to/from/around the subject to get different perspectives.

There is no doubt that changing focal lenght is important; most of my own lenses are zooms; but I use the zoom for filling the frame the way I want AFTER I have changed perspective by moving the camera relative to the subject.

--
[email protected]

 

[gdgeisler]

" Zoom = magnification. Move = change perspective"
I think that's been concluded.

Cropping, magnification... potatoe pototoe.

Gerry

 

[gwprovost]

And well said.

Zooming changes only the magnification of the image.

Moving the camera relative to the subject changes the perspective.
What people consider a change in perspective from only a change in
focal lenght is NOT perspective change, pure and simple.

Vocabulary-challenged photographers sometimes call it "apparent
perspective" or "compression". But changing focal length from
fixed position while enlarging/reducing to keep constant image size
on output medium proves that focal length it is only a
magnification change, not a perspective change

That is why knowledgable photography instructors tell their
students to avoid relying on zoom lens; they tell them to MOVE
to/from/around the subject to get different perspectives.

There is no doubt that changing focal lenght is important; most of
my own lenses are zooms; but I use the zoom for filling the frame
the way I want AFTER I have changed perspective by moving the
camera relative to the subject.

--
[email protected]

 

[amtberg]

I use the zoom for filling the frame
the way I want AFTER I have changed perspective by moving the
camera relative to the subject.

Good advice.

 

[Alan Martin256506]

So my question is...

Is Zooming in EXACTLY the same as physically moving closer to the
subject? Or is there some price to pay for being lazy and using
the Zoom ring instead of actually getting up and walking closer?

And the answer is...

Zooming in produces telephoto compression (the "flattening" effect you describe), while physically moving closer avoids it. There is a definite difference.

Is telephoto compression a bad thing? Maybe, if you like a three-dimensional look in your photos. It depends on your personal preferences, and it also depends on the subject.

Petteri Sulonen suggests learning about perspective by going out and taking photos with just one focal length, until you get a feel for what it does for your images.

This might be more than you need, but I think it is a good idea to learn about perspective, so that you can choose focal lengths for artistic effect rather than just for convenience.

In other words, konstantinos_d got it right in the fifth reply to your post. Nothing he said there was wrong, but that post generated dozens of objections! So that my post doesn't suffer the same fate, I have given a much longer explanation below. Let this be a lesson to those who were so quick to attack the straightforward explanation: Just because something is different from what you have learned does not make it wrong.

I recall in a previous thread some discussion about the change in
perspective one gets from Zooming in. In short, conventional
wisdom says that image depth flattens as one increases focal length.

And the conventional wisdom is correct. More precisely, it is the field of view captured in the print that matters, rather than the lens itself. This means that if we consider different formats, the 35mm equivalent focal length should be used; and that if we crop or stitch, we can make one lens behave like a different one.

What is less well known is that the effect on image depth is also dependent on viewing conditions! (See the demonstration suggested toward the end of the post.)

The important point that many posters have missed is that perspective distortion (i.e., telephoto compression and wide-angle distortion) is NOT the same thing as perspective in the technical sense, even though it is often what is meant by the word "perspective" in photography. (That causes lots of confusion, as this thread illustrates.) Perspective distortion is actually a matter of perception.

The term "perspective" refers to effects such as foreshortening and changes in apparent size that result from projecting a three-dimensional scene down to a two-dimensional image. These effects are purely a function of the position from which the scene is viewed; that is, in photography, they depend on camera-to-subject distance - as many others have said.

But we learn at a very young age to compensate for these effects in order to understand our 3-D world. So although we see objects from many different perspectives even with our unaided eyes, they don't look distorted! (We can of course observe perspective effects, but they are expected so they don't look unnatural.)

In fact, we do more than just compensate for perspective: we actually use it as a depth cue (along with binocular parallax and motion parallax) to see the world in three dimensions. This also allows us to see a three-dimensional effect in two-dimensional photos.

But wide-angle and telephoto images do look distorted... what's going on? Actually, photos with different fields of view don't just capture different-sized pieces of the photographer's visual field and present them unaltered to the viewer.

Rather, the images are normalized in apparent size , because whatever the FoV captured, the print is normally viewed in the same way - over a FoV, in the viewer's visual field, similar to that of a normal lens. (In fact, "normal lens" is defined based on to the typical way of viewing large prints.) It is the change in apparent size, as compared with the original scene, that distorts the perception of depth!

The conventional wisdom is actually correct. The longer the focal length as compared with a normal lens, the more the apparent depth is compressed (telephoto compression). For short focal lengths, depth is stretched, but the photo also appears distorted in other ways (wide-angle distortion). This additional distortion occurs because the stretching is actually parallel to the optical axis, rather than directly away from the viewer's eye.

There is of course an assumption that prints are being viewed in a particular "normal" way. When this assumption breaks down, such as for small prints, perspective distortion is affected. But it is rare indeed for viewing conditions to be adjusted according to the FoV of each image! So the explanation above still applies, just with a different "normal" FoV.

Here is a neat demonstration of how perspective distortion depends on apparent size. Take a wide-angle photo that shows obvious distortion, like converging verticals in architecture, and display it on a large computer screen. View the image up close, so that it fills as much of your visual field as the original scene would have. Although the image is the same, it no longer looks distorted - in fact, it looks completely natural!

For best results, close one eye (to eliminate binocular parallax) and keep the other eye centered over the image. If your eyes require corrective lenses, use contact lenses if possible. Also, make sure there isn't significant geometric distortion (such as barrel distortion) in the image. Under ideal conditions, the effect can be quite dramatic.

Unfortunately, this experiment requires good near vision (more so for a more extreme wide-angle photo), unless you have an exceptionally large screen.

Back to the OP's remaining point...

An arguement was made that this "flattening" is not a result the
lens "distorting" perspective but rather, it is the exact same
effect as moving closer to the subject.

As explained above, this is not the case. Moving closer to the subject changes perspective but does not introduce distortion!

Zooming in place, on the other hand, does not change perspective but does introduce perspective distortion.

--
Alan Martin

 

[gwprovost]

...and don't bother reading any more than this;

And the answer is...

Zooming in produces telephoto compression (the "flattening" effect
you describe)

You are totally confused and don't have a clue as to what you're talking about.

Telephoto compression is a function of camera/subject distance ONLY and has NOTHING to do with zooming. There are countless explanations of this, and links to explanations of this, already in this thread. Do yourself and everyone on this forum a favor and do a little reasearch before embarrassing yourself.