Focal length for portrait from 10meters

[doga_d]

<p>Okay, so right know I'm using 50mm which is perfect for close-up portraits. However, I also want take portraits, or at least upper body, from a distance like 10 meters. For such purpose, what focal length would meet my requirements ?<br>

105mm or 135mm ? Or do I need something longer ?</p>

[MichaelChang]

<p>There is a tutorial (and calculator) here that will help determine your needs:<br>

<a href="http://www.cambridgeincolour.com/tutorials/camera-lenses.htm">http://www.cambridgeincolour.com/tutorials/camera-lenses.htm</a></p>

[doga_d]

<p>Oh that's cool, thanks so much !</p>

[dhbebb]

<p>To get the same size image at 10 meters as you do with a 50 mm lens at 2 meters, you need a lens 5 times as long, in other words 250 mm. BUT ... for most people, the resulting perspective will be too flat, not to mention the fact that the subject will be a long way away and communication will be difficult. A lens of 85 or 90 mm is considered a normal portrait lens for 35 mm film or full-frame digital.</p>

[dcstep]

<p>I'm not sure why you're at 10m, but I'd use my 70-200mm.</p>

[ellis_vener_photography]

"BUT ... for most people, the resulting perspective will be too flat"

 

Oddly many fashion and swimsuit photographers use super telephotos aforementioned their portrait type work and do not

have that problem. In theory you are correct, but for some types of portrait work it yields a stronger more visually

compelling photograph.

[dhbebb]

<p><em>many fashion and swimsuit photographers use super telephotos </em><br>

True - I was thinking of studio work, where a 250 on 35 mm would in my view be pointless. It has of course been fashionable with fashion and swimsuit work to shoot out of doors and use a longer lens at full aperture for a very narrow depth of field - if this is what dogo wants, fine!</p>

[chris_waller]

<p>For head and shoulders portraits I use either an 85mm, a 100mm or occasionally a 135mm. Even for full length portraits I would us the 85mm or 100mm.</p>

[Alan Marcus]

<p>This is a long debated issue regarding the choice of focal length for portraiture. The desire is please the subject who has a predetermined view of themselves derived from their makeup mirror or shaving mirror. We are talking about imaging the human face and delivering the makeup mirror perspective. If the focal length selected is too short, likely the image will be distorted. We are saying nose reproduced slightly too big and ears slightly too small. This is because things close to the camera reproduce larger than things further away. If the lens used has too long a focal length this delivers a flattening effect. Such distortions, even if microscopic, cause people to say, "I don't photograph well".</p>

<p>To record an image with a near natural perspective, science tells us to take into account the viewing distance of the displayed picture and the magnification that it took to enlarge the image to the display size.</p>

<p>Talking about a full frame format (24mm by 36mm), to make an 8x10 requires about 10x magnification of the negative or the digital image. Now if we make an 8x10 it is likely to be placed on a dresser or mantel and viewed from a distance of 1 meter (1 yard).</p>

<p>Let us do the math: The formula is focal length multiplied by magnification = viewing distance.</p>

<p>If we mount a 100mm and then make an 8x10 (10x magnification), the viewing distance works out to be 100 x 10 = 1000mm = 1 meter or about 1 yard. Such a displayed image will be perceived as having the correct perspective.<br>

<br>

Out of all this gobbledygook comes a rule of thumb. For portraiture purposes, best to use a focal length that is about 2 times to 2 1/2 times the diagonal measure. This rule takes into account both the viewing distance and the magnification (for most portraits) and helps us choose a suggested focal length. For the full frame, the diagonal measure of the format is 43mm. Thus, the suggested portrait focal length is 85mm through 107mm. Most gravitate to a 105mm.<br>

For the compact digital, format (16mm height by 24mm length) the diagonal measurement is 30mm. Do the math and the suggested focal length is 60mm through 75mm.</p>

<p>Rules of thumbs are not engraved in stone; you are free to follow your heart. </p>

[Spearhead]

<blockquote>

<p>The desire is please the subject</p>

</blockquote>

<p><br /> Plenty of portraiture is done with no "desire" to please the subject. And "please" is personal, not universal as the post suggests. Once that is understood, it all becomes very different.</p>

[Brad_]

>>> To record an image with a near natural perspective, <B>science</b> tells us ... Let us do the

<B>math</b>: The formula is focal length multiplied by magnification = viewing distance ... For portraiture

purposes, best to use a focal length that is about 2 times to 2 1/2 times the diagonal measure. This

<B>rule</b> takes into account... <P>

 

I'm an engineer who has studied a ton of "science," have done a lot of "math", and am aware of a lot of

"rules." <P>

 

And I've made a lot of portraits.When doing so, I leave my science books at home, my sliderule sheathed,

and my mind empty of rules. It all seems to work out...<P>

 

 

>>> Rules of thumbs are not engraved in stone; you are free to follow your heart.<P>

 

Ahhhhh. I can breath again...

[Alan Marcus]

<p>“And how many hours a day did you do lessons?' said Alice, in a hurry to change the subject.<br />Ten hours the first day,' said the Mock Turtle: 'nine the next, and so on.'<br />What a curious plan!' exclaimed Alice.<br />That's the reason they're called lessons,' the Gryphon remarked: 'because they lessen from day to day.” <br />― <a href="/author/show/8164.Lewis_Carroll">Lewis Carroll</a>, <em><a href="/work/quotes/2375385">Alice's Adventures in Wonderland & Through the Looking-Glass</a></em></p>