Why are some lenses flattering for facial pictures

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I could do with a little help here as I've puzzled over this for a while.
Certain lenses seem to flatter facial features whilst other can get very pointy and enhance all the wrong features. The thing is I don't undertand why as glass should be glass - I understand that c 50mm is the preferred focal length but I had can 17-40 L which was not good for anything facially whilst I have a Tamron 17-50 which is quite flattering. Can someome point me I the right direction as I'm confused.
 
Perspective - the combination of the angle of view and the distance between subject and camera to achieve the same composition in the frame with different focal lengths.

Hopefully you've remembered your Pythagoras..
 
It's camera to subject distance thing.

With a wide angle lens you have to get very close to get a tight head shot and you'll see the big nose effect. Shoot with a wide angle lens from the same distance you'd be at with a long zoom and then crop the wideangle shot for the same field of view as with the long zoom shot and the images would be the same, with no big nose effect.
 
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Alastair said:
Perspective - the combination of the angle of view and the distance between subject and camera to achieve the same composition in the frame with different focal lengths.

Hopefully you've remembered your Pythagoras..
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Ha it had to be useful for something!:) Thinking about it like that it makes perfect sense
 
woof woof said:
It's camera to subject distance thing.

With a wide angle lens you have to get very close to get a tight head shot and you'll see the big nose effect. Shoot with a wide angle lens from the same distance you'd be at with a long zoom and then crop the wideangle shot for the same field of view as with the long zoom shot and the images woild be the same, with no big nose effect.
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Im going to try this when I get home as I hadn't thought about the field of view - I think I may have even grasped this now - Thanks very much
 
It's not so much the field/angle of view as that only controls how much of the scene you record. It's just the distance.

If you photographed someone with a 100mm lens and a 17mm lens from the same distance, then cropped the 17mm lens image so it covered the same area as the 100mm lens image, the perspective would be the same for both of them.


Steve.
 
I think that this is something that we need to do ourselves and see for ourselves. The theory is one thing but seeing it in reality makes it all clear and obvious :D

And of course the distance issue is why a 20mm lens on FF can give people a big nose but on a smaller format when shooting with a 20mm they look just fine... because with the smaller format we are effectively shooting from a longer lens distance and cropping the image.
 
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Basically, it is all down to camera to subject distance. Fields of view, focal length and sensor size just cloud the issue.

Try it without a camera. Find a willing victim and look at him/her from various distances to see how the perspective changes.


Steve.
 
There's also the question of good bokeh, which is not just the ability to throw the background into a smooth creamy blur, as opposed to a distractingly busy edgy blur. Another component of good bokeh is making a smooth unobtrusive transition from parts of the face sharply in focus to those not quite in focus. This is sometimes optimised in specialised portrait lenses by leaving in some carefully adjusted & sometimes user adjustable spherical aberration. Fuji (56mm) & Sony (135mm) offer expensive portrait lenses with an apodisation filter, argued to offer the best bokeh so far possible.
 
Steve Smith said:
It's not so much the field/angle of view as that only controls how much of the scene you record. It's just the distance.

If you photographed someone with a 100mm lens and a 17mm lens from the same distance, then cropped the 17mm lens image so it covered the same area as the 100mm lens image, the perspective would be the same for both of them.


Steve.
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What about compression? I'd be very surprised if a 17mm lens gave the same perspective as a 100mm lens as longer focal lengths compress the image to bring the foreground and background closer together.
 
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Traditionally soft focus lenses were preferred for portraiture. Razor sharp macro type lenses are not flattering generally.
 
snerkler said:
What about compression? I'd be very surprised if a 17mm lens gave the same perspective as a 100mm lens as longer focal lengths compress the image to bring the foreground and background closer together.
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No. The focal length just affects the angle of view. The perspective is identical as long as the subject to camera distance remains the same. The long focal length just gives you a cropped version of the image from the wider lens.


Steve.
 
"Wide angle perspective" and "telephoto compression" are common misconceptions/misnomers... they don't really exist; it's just "perspective" or "relative distances."

If I have a subject 5ft away, and there is another object 5 ft behind it, then the distance between them will seem relatively large, it is equal to the distance between me and the subject. But if I back off to 50ft from the subject then the distance between the two objects is now relatively small (just 10%) and they will seem to be closer together.

And this is why shooting from shorter distances than typical human separation is "unflattering." It causes the distances between facial features to appear greater than we are used to (i.e. noses become longer). The choice of FL is simply a choice of composition (what is included in the image).
It's interesting that when we actually see a person at shorter distances than typical our brains "correct" the perspective so that we "see" what we are used to seeing (expect to see). But our brains do not do that when viewing a picture for some reason.
 
sk66 said:
"Wide angle perspective" and "telephoto compression" are common misconceptions/misnomers... they don't really exist; it's just "perspective" or "relative distances."

If I have a subject 5ft away, and there is another object 5 ft behind it, then the distance between them will seem relatively large, it is equal to the distance between me and the subject. But if I back off to 50ft from the subject then the distance between the two objects is now relatively small (just 10%) and they will seem to be closer together.

And this is why shooting from shorter distances than typical human separation is "unflattering." It causes the distances between facial features to appear greater than we are used to (i.e. noses become longer). The choice of FL is simply a choice of composition (what is included in the image).
It's interesting that when we actually see a person at shorter distances than typical our brains "correct" the perspective so that we "see" what we are used to seeing (expect to see). But our brains do not do that when viewing a picture for some reason.
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Interesting. I've read many blogs etc like this that just show the effect of focal length, and suggest it's the FL of the lens rather than subject distance.
http://photography.tutsplus.com/tutorials/exploring-how-focal-length-affects-images--photo-6508


I'm going to have to try it myself now ;)
 
snerkler said:
Interesting. I've read many blogs etc like this that just show the effect of focal length, and suggest it's the FL of the lens rather than subject distance.
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The bit that they usually miss out is that the focal length of the lens makes you change your position relative to the subject.

As an example. If you put a 100mm lens on your camera and took a head and shoulders portrait of someone then took another shot from the same position but with a 24mm lens, you could then crop the wider shot to head and shoulders and apart from the reduced resolution, the pictures will be the same.

If you don't move, the relationships between all of the objects in the scene cannot possibly change.

This is no different to a compact camera with a tiny sensor using a 7mm lens and a DSLR using a 50mm lens. Either can produce similar images from the same place but the focal lengths and the magnification when viewing are very different.


Steve.
 
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The problem is "perspective" has two meanings. It has a literary meaning, i.e. "point of view"/angle. And it has a graphical meaning, i.e. spatial relationships.

Even I use both meanings when talking about photography which is what causes the confusion, but I try to point out the contextual differences.
 
sk66 said:
Try this; Pick a distance/subject and photograph it with a wide lens and a long lens. Then crop the wide image in post to include the same composition as the long lens... the images will be the same (assuming no lens specific distortion).

Or, I've done it for you...http://photographic-academy.com/creating-a-picture/85-creating-a-picture/133-more-on-lens-selection
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Thanks, that's what I was going to do but you've saved me the trouble, assuming I trust your methodology of course :p ;)

Every day's a school day ;)
 
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I've always tried to fill the frame by getting up close when id be better zooming in , if im reading you all right. I need to experiment now!
 
Overexposed said:
I've always tried to fill the frame by getting up close when id be better zooming in , if im reading you all right. I need to experiment now!
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Well of course that depends on the look you want to acheive ;)
 
Steve Smith said:
The bit that they usually miss out is that the focal length of the lens makes you change your position relative to the subject.

As an example. If you put a 100mm lens on your camera and took a head and shoulders portrait of someone then took another shot from the same position but with a 24mm lens, you could then crop the wider shot to head and shoulders and apart from the reduced resolution, the pictures will be the same.

Steve.
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Not sure I absolutely agree with that statement.
A long lens pulls the background closer and flattens the look of the distance between objects, a wider angle lens does the opposite so cropping a wider lens shot will give a different "look" to the photograph. Bear in mind also using the same aperture on different lenses focused at the same subject to camera distance will give different dept of field, obtaining the same image on different lenses will be difficult to achieve.

As an aside a longer lens often allows the photographer to be further away from the subject which results in the "sitter" feeling more relaxed as they dont have a camera wedged up their nose (which would be the case in the case of frame filling, distorted perspective wide angle lens), it's a psychological thing rather than a physical difference in the lens. This is another reason why some lenses are seen as "better" suited to portrait photography, you get reasonable separation between the subject who may be tense if their personal space is invaded by the photographer resultiing in a tense/stilted image, unless of course you want a fish-eye distorted big nosed portrait. :)

Matt
 
If we consider the full frame format (35mm) then a short telephoto lens in the region of 85/90mm will give the most pleasing perspective of and individuals face without distorting it. This focal length is universally accepted as a 'the portrait lens' for that reason.
 
sk66 said:
Try this; Pick a distance/subject and photograph it with a wide lens and a long lens. Then crop the wide image in post to include the same composition as the long lens... the images will be the same (assuming no lens specific distortion).

Or, I've done it for you...http://photographic-academy.com/creating-a-picture/85-creating-a-picture/133-more-on-lens-selection
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Great illustration, and special bonus points for this:

This is why you cannot "zoom with your feet." An image looks entirely different taken with a shorter focal length from closer than it does if taken with a longer focal length from further away.
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It's amazing just how many people don't understand that... "28mm? Just use a 35mm and take a few steps back" :banghead:
 
MatBin said:
Not sure I absolutely agree with that statement.
A long lens pulls the background closer and flattens the look of the distance between objects, a wider angle lens does the opposite
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Again, it's not the FL causing it. It's due to the difference in subject distance as a result of using a different FL. Cropping a wider shot taken from the same distance will look the same. See the link I posted above for examples, or try it yourself.

The exact same thing is happening all around you all the time... just look down the street and notice how much "closer together" things appear the farther away they are (i.e. a row of parked cars).
 
^^ All of those will have been taken at different camera to subject distances.


Steve.
 
Steve Smith said:
^^ All of those will have been taken at different camera to subject distances.


Steve.
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Obviously. Subject distance and focal length are directly linked if you want to maintain subject size in the frame. Wide angle lenses are a problem for headshots because they "force" you to get too close.
 
A few years ago in Amateur Photographer magazine, Geoffrey Crawley was testing a very wide angle lens. In the article he showed a photograph of a London bus which was so 'distorted' out of shape that it looked as if it was a cartoon bus.

The caption to the photograph stated 'There is nothing wrong with the lens. This is what the bus actually looks like from this close distance'.

Here is another experiment to try to prove that perspective is a distance thing. On a piece of paper, draw a dot to the left and call this the camera position. Now draw a selection of square shapes in random places on the paper to the right. These represent objects in the image. Now draw straight lines from the camera position to all of the corners of the squares which show the angles formed by the width of the objects relative to the camera position. Now change your camera's lens for one of a much different focal length. Did anything change on the paper?


Steve.
 
Steve Smith said:
A few years ago in Amateur Photographer magazine, Geoffrey Crawley was testing a very wide angle lens. In the article he showed a photograph of a London bus which was so 'distorted' out of shape that it looked as if it was a cartoon bus.

The caption to the photograph stated 'There is nothing wrong with the lens. This is what the bus actually looks like from this close distance'.

Here is another experiment to try to prove that perspective is a distance thing. On a piece of paper, draw a dot to the left and call this the camera position. Now draw a selection of square shapes in random places on the paper to the right. These represent objects in the image. Now draw straight lines from the camera position to all of the corners of the squares which show the angles formed by the width of the objects relative to the camera position. Now change your camera's lens for one of a much different focal length. Did anything change on the paper?


Steve.
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:eek: Nobody told me there was going to be a test !
 
sk66 said:
Try this; Pick a distance/subject and photograph it with a wide lens and a long lens. Then crop the wide image in post to include the same composition as the long lens... the images will be the same (assuming no lens specific distortion).

Or, I've done it for you...http://photographic-academy.com/creating-a-picture/85-creating-a-picture/133-more-on-lens-selection
Click to expand...

Gosh a few picture save an headache sometime! That just illustrate the whole thing and it make sens.

If lens were able to affect the perceptive it mean they would be some weird application to this. For exemple if an object is hidden behind another. Whatever the lens if you don't move you won't see it. If the perspective was change you would be able to see things that are behind other object just by changing the lens. Sorry, i might be talking rubbish just a very very late before bedtime idea that run through my brain.
 
167729319fba5e8ffad94cdd6a846e2c.jpg


http://stepheneastwood.com/tutorials/lensdistortion/IMAGES/tile1.jpg

I think this illustrates it well, I saw a while back and mentally bookmarked for such a discussion :)
 
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