Picking the right focal length makes all the difference

[Mainecoonmaniac]

http://www.danvojtech.cz/blog/2016/07/amazing-how-focal-length-affect-shape-of-the-face/

 

[MattKing]

Nice set of examples, but the comments below are bang on - it isn't the change in focal length that does this, but rather the change in camera to subject distance (and the corresponding change in perspective). The change in focal length allows the photographer to fill the frame with the subject.

 

[cowanw]

I find this subject interesting. As capture size (to ULF) increases some say that the closer subject distances are less of an issue. I wish I could do this in Ultra large format and test that for myself.

 

[mike c]

How does focal length and distance affect a slender persons portrait compared to a heavier set persons portrait?

 

[GRHazelton]

A wonderful demonstration of the effect of focal length on the rendering of a familiar subject, with the constraint that the image is to be the same size in each image. Reminds me to put away that ultra-wide 18mm lens when shooting portraits! I really favor my Pentax Takumar 135mm f2.5, good focal length and fast enough to blur the background

I think it was David Vestal in his excellent The Craft of Photography who approached the focal length/perspective question from another way. He photographed the same scene FROM THE SAME CAMERA POSITION, using different focal length lenses. Then he presented an enlargement of the same object, a car I think, from each photograph. The enlargement was the same size for each focal length. The perceived perspective of the car and its immediate surroundings was unchanged regardless of the lens' focal length. His point was that camera position and distance to the subject is what influences perspective, not focal length.

Do note that the selected object, the car, had to be pretty much in the center of the frame for it to be included in all images.

 

[GRHazelton]

How does focal length and distance affect a slender persons portrait compared to a heavier set persons portrait?

Should be the same way, although perhaps not as obvious. Remember the old saying that the TV camera added 20 pounds? I wonder what the TV camera lens focal length correlated to 35mm practice.

 

[wiltw]

How does focal length and distance affect a slender persons portrait compared to a heavier set persons portrait?

This is a good rendition of variance in facial changes associated with very short distance vs. very long distance, to keep face the same proportion of the total frame area.

www.stepheneastwood.com/tutorials/lensdistortion/index.htm

It is DISTANCE (camera position relative to subject), and absolutely not FL, which determines perspective.

I can shoot the same object from the same camera position, with 20mm vs. 200mm, and simply crop the shot and enlarge to same final 8x10 print size, and the subject will be IDENTICAL in facial rendition with 20mm or 200mm lens...only grain and detail may differ in the shots.

 

[Vaughn]

"His point was that camera position and distance to the subject is what influences perspective, not focal length."

But if you are using only one non-zoom lens, then the focal lenght is what determines the camera position and distance to subject...and thus perspective. Just another way of looking at it.

 

[mike c]

Thankyou Vaughn,wilton and GRhazelton. I can see that the closer you are with the camera distance that distortion increases with a shorter focal length lens, but it also thins the profile of the face as wilton's example, and as you move away from the subject using a longer lens the face fills out a bit. I realize this is do to the increased distance from camera to subject and distortion being reduced, but for Portrait's of very full faced (plump faces) it would be an advantage to using a shorter length lens (not necessarily wide angle) at a lesser distance to thin that face a bit being careful not to add too much distortion. And using a longer lens at longer distance to fill (fatten up) a very thin persons head. I suppose the nose and the eyes (maybe ears too) have a lot to do with this.

 

[MattKing]

Thankyou Vaughn,wilton and GRhazelton. I can see that the closer you are with the camera distance that distortion increases with a shorter focal length lens, but it also thins the profile of the face as wilton's example, and as you move away from the subject using a longer lens the face fills out a bit. I realize this is do to the increased distance from camera to subject and distortion being reduced, but for Portrait's of very full faced (plump faces) it would be an advantage to using a shorter length lens (not necessarily wide angle) at a lesser distance to thin that face a bit being careful not to add too much distortion. And using a longer lens at longer distance to fill (fatten up) a very thin persons head. I suppose the nose and the eyes (maybe ears too) have a lot to do with this.

wiltw's linked examples have a problem in that the examples are not matched well.

The cropping should be adjusted to ensure that the eyes are exactly the same distance apart in all cases. In addition, the face should be at the same angle to the camera in all cases. Neither situation applies with respect to those examples.

I think you will find that if the examples are properly matched the only people who might be flattered from a close working distance are those with very flat (not plump) faces.

 

[Reinhold]

A few years ago I made a PowerPoint presentation to a group of emerging photo enthusiasts.
The confusion over focal length -vs- camera position was(is) common.
Here's one of the slides I used to illustrate the subject.
That, plus a hands-on demonstration using an RB-67 and several lenses settled the mis-understanding.

Reinhold
www.classicBWphoto.com

 

[mike c]

Thankyou Reinhold for the illustration, very nice example. Matt, I do know a couple of flat heads, again thanks for your input.

 

[michr]

Chiming in with the others to say subject distance determines perspective not the lens per se. You can see this effect with your own eyes, eliminating the focal length variable completely.

Don't stick a lens in someone's face unless you want to exaggerate their features and make them look less attractive.

 

[benjiboy]

I'm primarily a portrait photographer and have been aware of the way focal length effect the way the face is rendered for many years, and why they will have to prise my Canon FD 85mm f1.2 L lens out of my cold dead hands, because of the way 85mm lenses draw their image of the human face and the way they reproduce the background is perfect for portraiture, I bought the lens new more than thirty years ago and it cost much more than I could afford but I've never regretted it.

 

[ic-racer]

As MattKing pointed out, focal length changes the angle of view. Moving camera position changes perspective. An example of different focal lengths might look like this:

 

[wiltw]

I did this illustration for another forum, to illustrate the point that camera-to-subject distance -- and NOT FL -- is what changes 'perspective'. (No point reinventing the wheel.)

http://photography-on-the.net/forum/showthread.php?p=7667313

 

[Slixtiesix]

Thank you so much for sharing this! This is one of the best - if not the best - focal length comparison for a given frame space I have seen so far.

 

[Steve Smith]

How does focal length and distance affect a slender persons portrait compared to a heavier set persons portrait?

Not at all. Only the distance from the subject to the camera makes a difference.

If you set a camera up 8' from the subject and take a photograph with a 135mm lens then a 50mm lens, the perspective will be the same on both. The only difference will be that the 50mm lens will show a wider view. Crop it to the same view as the long lens image and the look will be the same.


Steve.

 

[Halford]

A few months ago I needed to get a passport-type photo taken for a visa for a country whose embassy is known among photographers to be particularly picky about the photo rules. The photographer complained that he couldn't see my ears in the shot so made me go trim my sideburns. I came back trimmed and he said that no, he still couldn't properly get my ears into the picture.
"Look," I said, "they can't refuse me a visa because of the shape of my face. So why don't you zoom in with your lens and take a few steps back, and you'll see them."

He wouldn't believe me ... until he did it, and could suddenly see my ears.

 

[iandvaag]

I think what I'm about to say is correct, but I must admit I'm still internalizing this basic fact about photography myself.

What is often forgotten nowadays is the print. It's an interesting exercise to consider the physical size of a print and the distance from which the print is viewed.

The following is assuming you fill the frame with an object. When you move to a longer lens, you must physically move the camera away from the object an appropriate amount so it still fills the frame; when you move to a wider lens you move the camera closer to the object. This is in line with what others have said above -- the distance from the lens to the subject is actually what determines perspective, not focal length. However, if you fill the frame with an object, the lens-subject distance is proportional to focal length, so it is reasonable to discuss in terms of focal length.

If printed sufficiently large and viewed from sufficiently close, a photograph made with a wide angle lens will have the "correct" perspective. Likewise, if printed sufficiently small and viewed from sufficiently far away, a photograph made with a telephoto lens will have the "correct" perspective. For example, consider the following two photographs made on 35mm film and enlarged:
An 11" by 17" print made with a 21mm lens
A contact print (24mm x 36mm) made with a 250mm lens

If these two photographs are viewed from a distance of 25cm, they will both show the same (correct) perspective.

Now consider the following:
A 5x7 inch print made with a 21mm lens and viewed from a distance of 10cm
A 5x7 inch print made with a 250mm lens and viewed from a distance of 125cm

Once again, these two prints, when viewed from the specified distance will show the same (correct) perspective.

Of course, it's difficult to control the distance from which a print is viewed.

I attached an image, adapted with permission from Dan Vojtech's article where I resized several frames taken from different distances so that they show approximately the same perspective when viewed from any distance. It's not perfect, but I think it illustrates that print size and viewing distance affect perspective.

If an image is printed at 1:1 (life size), and you view the print from the position where the camera took the photo, it will have correct perspective. (For example try it with this photo from: https://www.ephotozine.com/article/shooting-portraits-from-different-angles-17169)

Put more simply, if you stand in the same spot and take a photo with a wide lens and a telephoto lens, both photos will show the same perspective, only the field of view is different. So, chose where you stand to obtain the perspective you want, and then choose a focal length that "crops" the scene to make the frame you want.

 

[cliveh]

As said, camera to subject distance controls perspective, but a telephoto lens allows you to fill the format.