How to Choose Your Next Portrait Lens—Part 2

Portrait lenses and focal length

One of the most dis­cussed and mis­un­der­stood prop­er­ties of por­trait lens­es is focal length. If you ask your pre­ferred online com­mu­ni­ty for por­trait lens sug­ges­tions, chances are, many users will respond by rec­om­mend­ing spe­cif­ic focal lengths. 

Per­haps the most com­mon­ly rec­om­mend­ed focal length for por­trai­ture on full-frame cam­eras is 85 mm; oth­er pop­u­lar focal lengths include 50 mm, 105 mm, 135 mm, and 70–200 mm zooms. If you’re at all famil­iar with the con­cept of focal length, you should notice that most of these sug­ges­tions are in the short to medi­um tele­pho­to range.

When explain­ing their rec­om­men­da­tions, pho­tog­ra­phers claim that wide-angle lens­es make faces look bad or that such-and-such focal length is too wide for por­traits. When this sen­ti­ment is left as-is, the unfor­tu­nate impli­ca­tion is that some inher­ent and mys­te­ri­ous qual­i­ty of wide-angle lens­es caus­es ugli­ness and that longer focal lengths pro­vide the solu­tion. To help you under­stand these warn­ings and sug­ges­tions, I’ll briefly explain the con­cepts of scale and per­spec­tive distortion.

Scale, focal length, and perspective

In my Com­po­si­tion for Begin­ners video, I touched upon the con­cept of scale, which I use to describe the appar­ent size of your sub­ject with­in the pho­to­graph­ic frame. Your subject’s scale is deter­mined by two fac­tors when you’re tak­ing a pic­ture: focal length and per­spec­tive. 

The focal length of a lens deter­mines its mag­ni­fy­ing pow­er. This is the appar­ent size of your sub­ject as pro­ject­ed onto the focal plane where your image sen­sor resides. A longer focal length cor­re­sponds to greater mag­ni­fi­ca­tion and a larg­er ren­di­tion of your sub­ject, and a short­er focal length results in less mag­ni­fi­ca­tion and a small­er ren­di­tion of your subject.

The appar­ent size of a sub­ject at a fixed dis­tance from the cam­era is direct­ly pro­por­tion­al to the lens’s focal length. So, for exam­ple, if you pho­to­graph a kid hold­ing a beach­ball and then switch to a lens that is twice the focal length of the first, the ren­dered size of every ele­ment in your image, from the kid to the beach­ball, will be dou­bled in size along their lin­ear dimensions—meaning in height and width. That’s how focal length affects scale.

In pho­tog­ra­phy, per­spec­tive is your camera’s point of view and is deter­mined exclu­sive­ly by the posi­tion from which a pho­to is tak­en. For sim­plic­i­ty, con­sid­er this the cam­era-to-sub­ject dis­tance. Changes in the sub­jec­t’s dis­tance have an obvi­ous effect on their per­ceived scale in a pho­to­graph. Ask your sub­ject to come half as close, and they’ll appear twice as large; ask them to move twice as far back, and they’ll appear half as small. That’s how per­spec­tive affects scale.

To main­tain an equal sub­ject scale in the frame, the focal length and sub­ject dis­tance must change lin­ear­ly, togeth­er and in the same direc­tion. If your sub­ject dou­bles their dis­tance for a giv­en scale, you will have to dou­ble your focal length to main­tain the orig­i­nal scale; if your sub­ject halves their dis­tance, you’ll have to halve your focal length. For exam­ple, if you like the scale of your sub­ject at 50 mm, but cir­cum­stances force the pho­to to be tak­en from half the ini­tial dis­tance, you’ll need to use 25 mm to obtain the orig­i­nal scale. Unfor­tu­nate­ly, short­en­ing the sub­ject dis­tance can result in per­spec­tive distortion.

Perspective distortion and telephoto compression

In pho­tog­ra­phy, per­spec­tive dis­tor­tion is an inevitable con­se­quence of how sub­ject dis­tance affects scale. Objects that are close to the cam­era appear much big­ger rel­a­tive to objects that are far­ther away. So, for exam­ple, Gin­ger looks three times larg­er than Vio­let because Vio­let is three times far­ther from the cam­era. This rela­tion­ship will hold whether their dis­tances from the cam­era are 1 and 3 m, 5 and 15 m, or 20 and 60 m, respec­tive­ly, because in each case, Vio­let is three times far­ther than Gin­ger. 

This rela­tion­ship stops being true when the cam­era starts to change its dis­tance for the sub­jects whose dis­tances are fixed rel­a­tive to one anoth­er. The dis­par­i­ty in their appar­ent size will decrease as the cam­era moves fur­ther back until these dif­fer­ences become imper­cep­ti­ble. This effect is known as “tele­pho­to com­pres­sion”; how­ev­er, despite its name, it occurs in pho­tos tak­en with all focal lengths when a dis­tant sub­ject is vis­i­ble. Tele­pho­to lens­es make it more obvi­ous because the “tele-com­pressed” sub­jects are shown at a larg­er scale in the frame.

Perspective in portraiture

Gin­ger and Violet’s rela­tion­ship plays out on a small­er scale with­in the fea­tures of a sin­gle sub­ject. Peo­ple aren’t flat, and we’re not card­board cutouts; our faces, heads, and bod­ies have depth and dimen­sion. In a stan­dard por­trait, your subject’s nose is clos­er to the cam­era than their eyes, which, in turn, are clos­er than their ears. These dif­fer­ences are rel­a­tive­ly insignif­i­cant at long work­ing dis­tances. How­ev­er, they become sig­nif­i­cant at the very close sub­ject dis­tances required to achieve a “stan­dard” por­trait com­po­si­tion using a wide-angle lens. This leads to per­spec­tive dis­tor­tion, char­ac­ter­ized by a nose that looks too large rel­a­tive to the face, a nar­row­er head, and ears that appear pinned back. From extreme­ly close dis­tances, the cheeks can occlude the ears alto­geth­er. 

The char­ac­ter­is­tics attrib­uted to per­spec­tive dis­tor­tion are entire­ly a con­se­quence of the cam­era-to-sub­ject dis­tance. The focal length of a lens doesn’t direct­ly influ­ence per­spec­tive. This bears repeat­ing: focal length does not affect per­spec­tive. Despite this, it’s often blamed for the effect because dif­fer­ent focal lengths are used for dif­fer­ent pur­pos­es and vary­ing sub­ject dis­tances. Wide-angle lens­es are typ­i­cal­ly used from short­er dis­tances, lest the sub­ject appears too small in the pic­ture, while long focal lengths are gen­er­al­ly used from far­ther away, lest the sub­ject appears too large. 

The subject distance is the only factor in perspective distortion

Let’s dive a bit deep­er. You’ve prob­a­bly seen this or sim­i­lar effects before. Here’s a famous vari­a­tion, known as a “dol­ly zoom,” from the movie Jaws. This effect is cre­at­ed by tak­ing your first shot from a close dis­tance and using a short focal length. Take the sec­ond shot from slight­ly far­ther back and with a pro­por­tion­ate­ly longer focal length. And on and on. Such ani­ma­tions com­mon­ly illus­trate how dif­fer­ent focal lengths affect our per­cep­tion of appar­ent facial geom­e­try. Most exam­ples, such as this one by Dan V., label each frame’s focal length but omit the sub­ject dis­tance, which is arguably more impor­tant since you can’t have per­spec­tive dis­tor­tion with­out chang­ing your per­spec­tive. Since focal length doesn’t affect per­spec­tive, we can illus­trate the same effect by vary­ing the cam­era-to-sub­ject dis­tance with­out adjust­ing the focal length. Ini­tial­ly, the dis­tor­tion is dif­fi­cult to see because the sub­ject becomes small­er. How­ev­er, the per­spec­tive dis­tor­tion becomes obvi­ous when crop­ping each pho­to to equal­ize the subject’s scale through­out the sequence. Adding dis­tance labels instead of focal lengths cre­ates a much more prac­ti­cal point of reference.

How to choose the correct focal length for portrait photography

When some­one sug­gests that a par­tic­u­lar focal length is ide­al for por­trai­ture, they’re real­ly express­ing two pref­er­ences: one for the rel­a­tive appear­ance of facial pro­por­tions from a giv­en dis­tance and anoth­er for the subject’s scale with­in a com­po­si­tion. Only you can deter­mine whether you share the same pref­er­ences for both. 

Although there’s no ide­al uni­ver­sal dis­tance for por­trait pho­tog­ra­phy, we can find sev­er­al clues in prox­emics, which is the study of how peo­ple uncon­scious­ly struc­ture the space between them­selves and oth­ers. For exam­ple, con­sid­er the idea of inter­per­son­al dis­tance zones pro­posed by Edward T. Hall in 1966. These are divid­ed into the inti­mate dis­tance (from 0–45 cm), per­son­al dis­tance (from 45 cm to 1.2 m), social dis­tance (from 1.2 to 3.7 m), and pub­lic dis­tance (from 3.7 m and greater). Although these spe­cif­ic ranges are biased towards white Amer­i­can males and may not apply to you or your cul­ture, you like­ly have an approx­i­mate notion of what you con­sid­er com­fort­able inter­per­son­al dis­tances. 

Under­stand­ing this makes choos­ing the right focal length for por­trait pho­tog­ra­phy straight­for­ward. First, decide the approx­i­mate dis­tance from which you feel peo­ple look their best, and sec­ond, select a focal length that pro­duces the com­po­si­tion you want at your pre­ferred dis­tance. There­fore, if you pre­fer how peo­ple appear from longer dis­tances and favour tight­ly framed pho­tos that bor­der on head-n-shoul­ders, your style calls for a medi­um or longer tele­pho­to lens. Pho­tog­ra­phers who are par­tial to envi­ron­men­tal por­trai­ture, which show­cas­es peo­ple in their usu­al envi­ron­ment, can com­bine a long sub­ject dis­tance with a wide-angle lens. The per­mu­ta­tions are prac­ti­cal­ly end­less, so do what makes you happy.

Keep in mind: if you dis­cov­er a fond­ness for wide-angle close-scale por­traits, it’s impor­tant to know the ulti­mate pur­pose and audi­ence for your pho­tos. Researchers pho­tographed sub­jects simul­ta­ne­ous­ly from two cam­era dis­tances, 45 cm and 135 cm, in an exper­i­ment about the effect of per­spec­tive dis­tor­tion on social judg­ment. Exper­i­menters found that study par­tic­i­pants pre­ferred faces pho­tographed from out­side of the per­son­al dis­tance zone more than those pho­tographed from with­in it and rat­ed them high­er for attrac­tive­ness, com­pe­tence, and trust­wor­thi­ness. When you get an oppor­tu­ni­ty to pho­to­graph your favourite evil politi­cian, take a note from Pla­ton: get close and shoot wide. 

Jokes aside, this research was pub­lished in 2012, and mobile social media plat­forms have had years of explo­sive growth ever since. That means arms-length portraits—otherwise known as selfies—of celebri­ties, pub­lic fig­ures, and your secret crush are ubiq­ui­tous and acces­si­ble and pro­vide the gen­er­al pub­lic with con­stant expo­sure to exam­ples of per­spec­tive dis­tor­tion on con­ven­tion­al­ly attrac­tive faces, which is some­thing we weren’t privy to more than a decade ago. 

A final note on wide-angle vs telephoto for portraiture

One more thing: tele­pho­to lens­es have a unique ben­e­fit over wide-angle lens­es because their rel­a­tive­ly nar­row­er angle of view allows minute shifts in per­spec­tive to alter the photo’s back­ground dra­mat­i­cal­ly. It’s use­ful for remov­ing parts of the back­ground from the com­po­si­tion that you feel are dis­tract­ing. Since short focal length lens­es cap­ture a wider angle of view, equal­ly small move­ments will not accom­plish the same goal. 

Conclusion

And there you have it, a guide for choos­ing your next por­trait lens. Per­son­al­ly, my favourite lens for por­trai­ture is the Fuji­non 56 mm ƒ/1.2. It offers an angle of view equiv­a­lent to an 85 mm lens on full-frame cameras—so it’s a short tele­pho­to lens—features a huge ƒ/1.2 aper­ture at which it’s quite sharp, and has love­ly bokeh. With that in mind, I’ve used this lens for many oth­er sub­jects, rang­ing from still-life, street scenes, and land­scapes. This brings me to my final point: no mat­ter what lens you buy, no mat­ter what cat­e­go­ry of pho­tog­ra­phy it’s mar­ket­ed towards, I encour­age you to exper­i­ment using it on dif­fer­ent sub­jects and in a vari­ety of set­tings. Always explore and dis­cov­er, and don’t put your­self in a box. 

 If you have requests for future top­ics, let me know in the com­ments, and I’ll address them in future videos. In the mean­time, you can learn more about pho­tog­ra­phy on ExposureTherapy.ca. See you next time.

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