spot metering for portrait photography

posted in portraits, tutorials at May 23, 2011

When possible I prefer to use incident metering, which I described in my post How (and why) to use a hand-held light meter.  But sometimes you’ll want/need to take a spot meter reading.  Maybe you’re trying to take a candid image from across the room and it isn’t possible to walk up to your subject for an incident reading.  Maybe you don’t have an incident meter and want to use your camera’s built-in spot meter.  Maybe the scene is so extremely backlit that you can’t get an accurate matrix/evaluative reading. In any case, here’s how you do it.

When you spot meter correctly you’re actually using Ansel Adams’ Zone System.  I’m not going to get into the Zone System in detail because an in-depth understanding of the subject isn’t necessary for portraits.  All you need to do is to be able to estimate skin color.

What’s a spot meter?

Your camera probably has a built-in spot meter. My Canon 5D has a 3.5 degree spot meter, which covers the area of the center viewfinder circle. My Sekonic L-758 has a much more accurate 1 degree spot.  The spot meter is going to measure only the reading from inside the circle. So if your subject is, for example, heavily backlit and you put the spot on your subject’s skin, the backlit sun will not affect the reading.

Basic spot meter operation

(1)  set your camera on manual metering mode, set to spot metering

(2)  select your desired aperture

(3)  put the imaging circle on your subject’s skin then take your reading.  If using your camera’s meter, adjust your shutter speed until your meter is at the center zero point.

(4)  take your shot!

Simple, right?

Well, there’s a little bit more to it.

18% Gray

The above simple technique will only work perfectly if your subject’s skin tone approximately matches 18% gray, which is what your meter is calibrated for. *  Here’s what 18% gray looks like:

* Note: there is some dispute about the 18% gray figure. Some claim that meters are calibrated closer to 12%.  It’s a hotly debated topic on the internet for folks who didn’t have a date to the prom.

Your meter is going to assume that it is metering an 18% gray.  So if your subject is lighter than 18% gray, it’s going to turn it gray by darkening (underexposing) it.  If your subject is darker than 18% gray, it’s going to turn it 18% gray by lightening (overexposing) it.

Adjusting for skin tone

The trick to accurate spot metering is to adjust your exposure based on the brightness/darkness of your subject’s skin.  If you take pictures outdoors in snow, you know you’ll have to add +2 exposure, right?  Same principle here. Basically, light skin is going to require you to add exposure, dark skin will mean subtracting it.  So, for example, a very light-skinned person may require you to meter at +1.5.

Here are some examples of how I would adjust exposure for different skin tones. I may be slightly off, but I’m probably within a half stop or so. Close enough.

Here’s a mother and son with different skin tones.

If you’re struggling to estimate skin tones, imagine Halle Berry. (shouldn’t be too difficult for you guys out there).  She makes a perfect +0 neutral reading. Compare your subject’s skin to hers and adjust accordingly. It would be great to take her with me everywhere I go so I could use her to spot meter….

When using my hand-held spot meter, I use the exposure value to adjust my shutter speed. For example, suppose I’m metering a subject I estimate to be a +1 skin tone.  I’m shooting at f2.8 and the spot meter says 1/500 sec.  To adjust for the +1 skin I would simply set my camera’s shutter speed to give me one extra stop of light (1/250) and voila, perfect metering!  If using your camera’s meter, there’s no need to run any calculations in your head, simply adjust your shutter speed until the meter reads +1.

The hand trick

Let’s say you’re in the exact same light as your subject. You’re both under the shade of a tree on an extremely sunny day.  If you use your camera’s matrix/evaluative meter, you’re going to get a shutter speed like 1/2000 or something like that, which is going to severely underexpose your subject.  In this situation, I would use my hand-held meter for an incident reading. But what if you don’t have a hand-held meter?  Just set your camera’s meter to spot and use the procedure above.

But what if you’re not sure how to evaluate your subject’s skin?  You can use the old hand trick. With experience and a little testing, you can pinpoint your own skin’s exposure value.  Instead of taking a reading off of your subject, just take a spot meter off of your own hand and use that.  Example:  your hand is a +0.5.  Set your camera to manual mode, spot metering. Take the meter reading off of your hand and adjust your shutter speed until the meter reads +5.  Easy peasy.

For super accurate reading you can always carry a small 18% gray card with you and use that to meter off of instead of your palm.  No need to make any adjustments here – just set your shutter speed until the camera’s meter is at zero and you’re good to go.

Exercise

Do you like to people-watch for fun?  Try this exercise: the next time you do, look at each person who walks by and assign them an exposure value:  “she’s a +1, he’s a -0.5,”  etc.  Kinda geeky, but then I’m kinda geeky…

What about spot metering for landscapes, architecture, travel?

If you Google “zone system” you’ll find lots of resources here, but basically, here’s how I would meter non-portraits:

  • medium green grass:  +0
  • the north blue sky:  +0
  • average tree bark:  +1
  • snow:  +2
  • sunlight reflected off sand:  +2
  • shadows that you want to have some detail:  -2
  • dark leaves:  -1

That’s it.  Add spot metering to your bag of tricks, it will prove useful in many situations.

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  • filippo

    very clear and helpful, thank you! any consideration about b&w (like last post)? (May 23, 2011 | 11:03am)

  • admin

    I meter b&w the same as color. The one difference being that I rate b&w at box speed or faster, while I rate color film at box speed or slower. (May 23, 2011 | 08:03pm)

  • Jon Tsu

    Thanks another great post! Keep 'em coming. (May 24, 2011 | 01:42am)

  • Robert Gabriel

    Laurence, you should be a teacher. :) (May 24, 2011 | 04:21am)

  • Tim Parkin
    Twitter: timparkin

    It might be handy to point out the range of some 'media'. e.g. Most color negative films: -3 to +5 stops Most color transprency films: -3 to +2 stops Most black and white film: -4 to +5 stops Digital Camera: -4 to +3 stops If you place things at the extremes, you will get very light or dark but with a bit of texture.. (May 24, 2011 | 08:11am)

  • andrew r

    Mother & Son Photo. How do you set the exposure for a multi-coloured couple or group of people? Learned a lot from you. Thanks. (May 25, 2011 | 10:48am)

  • admin

    @andrew: just pick one person to base the exposure on. If you do it correctly, every person in the picture will have proper exposure. (May 25, 2011 | 02:11pm)

  • Chris Rowe
    Twitter: #!/ozthekeymaster

    Just found your blog through a David Du Chemin link on Twitter. Fantastic - thanks so much. Just want to say that "It’s a hotly debated topic on the internet for folks who didn’t have a date to the prom" is the funniest thing I've read in I can't remember how long. I will shamelessly rip it off now ;-) Thanks Laurence. (May 27, 2011 | 10:32pm)

  • Mark

    Great article Laurence. I do try the zone system for my portraits but with mixed results. That's perhaps because I'm ususally in av mode and my metering might not allways be as accurate. One question though, does this (zone system) also apply for working with flash? Meaning do I meter for the ambient light with + or - stop(s) exposure as described in your article and still use (fill) flash. Or is it mainly a scenario for backlit situations... (May 30, 2011 | 05:29am)

  • admin

    @Mark: Flash is another deal entirely. It depends on how much flash you want. Lighting a shot primarily with flash is a totally different scenario to adding a kiss of fill. If just adding a kiss of fill you can spot meter normally, set your flash to ettl with -1 or -1.5 FEC. (May 30, 2011 | 11:33am)

  • Alan Abrams
    Twitter: alanabramsphoto

    An absolutely perfect explanation of how digital cameras meter... (June 16, 2011 | 04:53am)

  • melody

    I really appreciate this info! I've been shooting film for a while now (mostly 400h) and feel like exposure has been so much guesswork. One question, in the image above of the man where you have the meter showing -0.5 exposure the light on camera right is brighter than camera left. Would you still meter for the shadow side? (July 02, 2011 | 09:13am)

  • admin

    @Melody: yes, I'd expose for the shadow side. (July 02, 2011 | 09:45am)

  • Kevin

    Laurence, your tutorials are some of the very best on the internet (IMHO at least!). Thank you so much for these! (September 14, 2011 | 12:41am)

  • Rachel

    Great info! Thank you! (October 24, 2011 | 08:35am)

  • Daniel Haggett
    Twitter: danielhaggett

    I have recently added an 18% grey card to my Canon 7d kit, as I am a bit obsessed about skin tones. There is so much arguing on the internet on the exact uses, and I have even read a few blogs that are just wrong. Really clear and concise stuff here. The pictures for skin tones are great. (February 01, 2012 | 02:39pm)

  • Julianna Rennard

    This is super helpful info and something I recently learned at a Tanja Lippert workshop. Since she shots only film, she sets her Nikon F-100 spot meter on and before doing anything goes in and meters for the subjects skin and then backs up adds those setting into her MF camera and starts shooting away. (February 20, 2012 | 04:48pm)

  • Steven

    In reference to your spot metering article: I have purchased a nice 18% gray card and if I put my digital camera on spot meter or use Pentax spot meter for my film camera I find that I do not get an accurate exposure. Example: I set the gray card against a flower vase on our living room table and left it there. Light was naturally diffused through a white curtain. I stood about 10 feet away and used my camera’s spot meter and set exposure on the gray card and took the shot. Then I shot the same shot with center weighted and Matrix meter. I compared the three exposures to what I was seeing with my eye as I viewed the scene live. Results: Spot meter was significantly over exposed. Matrix was very under exposed. Center weighted looked very close to what I was seeing with my eyes. The light was such that the gray card to the eye was medium dark. The spot meter made the gray card go to 18% which was incorrect in the lighting environment. It made the light more than it should be to make the gray card 18% which was a false level of light. Center weighted took the gray card into account and averaged it with the surroundings in its meter circle and gave the correct exposure. Matrix took too little of the gray card into account and under exposed. Question: What value does a gray card have if light is not bright enough to allow the card to be 18% gray? In dimmer light the card tricks the camera into lying and producing an overexposed image. I have used a gray card with natural light outdoor portraits in film and digital and the results have not been good. Exposure was always wrong. It is very frustrating. How can I measure exposure accurately? Thank you, Steven (May 07, 2012 | 10:21pm)

  • admin

    @Steven: It sounds like centerweighted works for you. I'd stick with it. (May 08, 2012 | 06:41am)

  • Andy Vu

    @Laurence: Well written with excellent sample images, I even bookmarked this link. I used spot meter 99.9% of my shooting and in addition to camera meter I also purchased a handheld meter. I clicked twice on the advertise link so you can have something return. (June 22, 2012 | 09:10am)

  • Justin Blair

    When shooting a subject with lighting in the background, can be the most challenging aspect of photography. I would agree with Laurence. If center-weighted works for you, go for it. For me, I continue to persist using spot meter (thanks to the techniques described her), and most of the times, it really works. The times that it doesn't, I keep taking the pictures at different shutter speeds, until I get the right exposure, and learn from it. This is important to me, because I'm occasionally asked to do a wedding, and the weirdest situations always occurs at the wedding, especially when you're taking pictures of the grooms dark suit and the brides white dress. If the photographer is standing in the same spot, and object is in the same location, you don't have to worry about metering again: just focus and shoot. (August 22, 2012 | 10:22am)

  • christopher Zydek

    hello,great article. i just started to shoot film again....and i do have a question. If you were shooting a bride wearing a white dress (outdoor) using a 400 Film (for example Portra 400). Would you expose for the dress using Spot metering (+2) ?? and would you set the iso at 400 or 200? or would you do something different ( let's say that you do not have a light reader!!) Thank you in advance (December 04, 2012 | 05:46am)

  • admin

    @Christopher: I only care about my subject. I meter for their skin. However, film has so much latitude that the white dress should be fine. If you are concerned about blowing out the dress, then simply rate the film at box speed. (December 04, 2012 | 05:56am)

  • Sia

    Hi, Unfortunately your suggestion to the question: Mother & Son Photo. How do you set the exposure for a multi-coloured couple or group of people? Doesn´t work. I have the same problem. If I base the exposure on the dark skin and adjust the meter the white people are underexposed and if I base the exposure on the white skin and adjust the meter the dark peoples are overexposed. So still I don´t know how to make a nice photo of multi-coloured couple or group of people? Perhaps Matrix or Center method!? Thanks, Sia (December 26, 2012 | 12:02pm)

  • admin

    @Sia: If you cannot get 2 people of different skin tones with decent exposure, then the problem may be to your camera's lack of dynamic range. My 5D Classic, a camera not known for great DR, can easily handle a light and dark person in the same frame. (December 26, 2012 | 12:27pm)

  • Kimberly

    Hey! This has helped me TREMENDOUSLY! I was definitely struggling with figuring out metering and your article has been the most helpful that I've found. I recently purchased a gray card to help me out and on the back of the card it says to increase exposure if I'm shooting a light-skinned individual. Do I do this even though I'm using a gray card to meter off of? I know your article said that using the gray card alone and adjusting shutter speed can be spot on so it has thrown me for a loop again! lol (May 31, 2013 | 03:29pm)

  • admin

    @Kimberly, no - either use the gray card to meter OR use your subject's skin to meter but increase exposure if your subject is light skinned. (June 01, 2013 | 06:29am)

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  • Terry Tedor
    Twitter: TerryTedor

    Begging your pardon, but not to quibble over details... The square you present as "18%" gray" is not "18% gray". The basic premise of your article is entirely correct, but the metering system doesn't meter to an 18% gray card, it meters to a REFLECTANCE of a gray card which happens to be 50% gray and is roughly equivalent to 18% of the incident light striking it, hence the name 18%. The square you show as "18%" is not even gray. It measures out at 133, 131, 134. A gray card with a reflectance of 18% measures at 128, 128, 128. (February 14, 2014 | 10:34pm)