Working distance between you and your subject.

[MattKing]

No sorry Mark, I can't agree it depends on the focal length of the lens, wheras this certainly applies to standard and wide angle lenses with medium telephoto lenses ie. 85, 90,100,135mm you can get tight head shots without distorting the facial features which is why they are considered "portrait lenses", once you get lenses longer than 135mm they have the opposite effect to large noses, and tend to flatten the features.

Ben:

I'm with Mark on this.

Perspective is determined solely by distance from your subject.

The focal length of the lens and the size of your film (or sensor) determines how large the image is on the recording medium.

If the format/film size/sensor size is first determined, you can choose a lens that allows a tight crop on the area of interest long with a good working distance.

Your examples of 85mm through 135mm lenses apply well to 135 film cameras. But they may not be long enough for medium format cameras, and would be wide angles for LF.

They could still be used with those larger formats, but in order to get a result with flattering perspective the photographer would need to stand far enough away for that, and the resulting image would be small on the film.

[benjiboy]

Ben:

I'm with Mark on this.

Perspective is determined solely by distance from your subject.

The focal length of the lens and the size of your film (or sensor) determines how large the image is on the recording medium.

If the format/film size/sensor size is first determined, you can choose a lens that allows a tight crop on the area of interest long with a good working distance.

Your examples of 85mm through 135mm lenses apply well to 135 film cameras. But they may not be long enough for medium format cameras, and would be wide angles for LF.

They could still be used with those larger formats, but in order to get a result with flattering perspective the photographer would need to stand far enough away for that, and the resulting image would be small on the film.
Perspective in the strictly scientific sense isn't what I was refering to but the effects of different focal lengths on the way that the human face it's shape and the relationship of one of it's feature to the other, and how they are rendered on film,
I used reference to the focal length used on 35mm cameras because that's what the majority of people understand and use, people using larger formats could translate it to the formats they use.
I base my remarks on more than four decades of practical portrait shooting, and if anyone want's to test their validity try shooting a close up headshot on 35mm with a 20mm lens.

[Diapositivo]

Yes. The guys who got too close aren't able to warn us.

That applies to Robert Capa as well, as he died on a mine during the Indochina war.

[MattKing]

Perspective in the strictly scientific sense isn't what I was refering to but the effects of different focal lengths on the way that the human face it's shape and the relationship of one of it's feature to the other, and how they are rendered on film,
I used reference to the focal length used on 35mm cameras because that's what the majority of people understand and use, people using larger formats could translate it to the formats they use.
I base my remarks on more than four decades of practical portrait shooting, and if anyone want's to test their validity try shooting a close up headshot on 35mm with a 20mm lens.

Ben:

I don't disagree with you that many of us do use our experience with the common "portrait" focal lengths for 35mm film when we consider this issue. The problem that occurs, however, is that trying to covert that experience for use with other formats can be both complex and subject to error.

I shoot several medium format formats, and in at least one case I have to add close-up accessories to my lenses to attain a close up headshot using an appropriate lens. In the end, for me it is simpler to arrive at a single, standard working distance for each intended result (full body portrait, 3/4 body portrait, upper torso and head portrait, shoulders and head portrait, close up headshot) and then choose the appropriate lens to match.

[benjiboy]

Ben:

I don't disagree with you that many of us do use our experience with the common "portrait" focal lengths for 35mm film when we consider this issue. The problem that occurs, however, is that trying to covert that experience for use with other formats can be both complex and subject to error.

I shoot several medium format formats, and in at least one case I have to add close-up accessories to my lenses to attain a close up headshot using an appropriate lens. In the end, for me it is simpler to arrive at a single, standard working distance for each intended result (full body portrait, 3/4 body portrait, upper torso and head portrait, shoulders and head portrait, close up headshot) and then choose the appropriate lens to match.
On Mamiya 6X6 TLRs I use the following lenses 80mm (52mm) 135mm (88mm) and 180mm (117mm),( the bracketed numbers are the 35mm equivelents ) which are fine for full length, head and shoulders, and tight headshots respectively, I move the tripod in the studio to get the correct distance and framing for that lens, I don't use close up lenses or any other afocal devices because unless they are the highest quality they can degrade the lens quality, and I have never found any need for them.

[cliveh]

Ben:Perspective is determined solely by distance from your subject.

How true and how important in composition.

[benjiboy]

Ben:

I'm with Mark on this.

Perspective is determined solely by distance from your subject.

The focal length of the lens and the size of your film (or sensor) determines how large the image is on the recording medium.

If the format/film size/sensor size is first determined, you can choose a lens that allows a tight crop on the area of interest long with a good working distance.

Your examples of 85mm through 135mm lenses apply well to 135 film cameras. But they may not be long enough for medium format cameras, and would be wide angles for LF.

They could still be used with those larger formats, but in order to get a result with flattering perspective the photographer would need to stand far enough away for that, and the resulting image would be small on the film.
I'm aware of this Matt, perhaps perspective isn't the right word, what I meant is the relationship between the foreground and the background and the tendency of standard and wide angle lenses to distort the human physiognomy if used at too close a distance and misrepresent the relationship of one facial feature with another, and the opposite effect of using too long a lens tends to flatten the features.

[wiltw]

Matt and Ben, I think you guys are using different expressions of the same fundamental point of agreement! Perspective is determined solely by distance from your subject. The focal length of the lens and the size of your film (or sensor) determines how large the image is on the recording medium.


Long distance with any lens, when reframed in the darkroom, would have the same flattening of nose regardless of the FL used to take the shot...and on that point your statement is in error, Benji, "effects of different focal lengths on the way that the human face it's shape and the relationship of one of it's feature to the other".

This post on another forum illustrates that it is NOT the focal length per se. Note the SAME PERSPECTIVE (relationship of subject to its surroundings) taken with three very different FL from the same camera position, when cropping in the darkroom brings us to same framing (photos 4,5,6 in the linked post)...

http://photography-on-the.net/forum/showpost.php?p=7667313&postcount=4