Guest Entry – Is a Hand Held Light Meter Really Necessary?

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This guest post is kindly provided to us by Steve Russell. You can contact Steve at steve.russell@russellpc.net.

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Is a Hand Held Light Meter Really Necessary?
By: Steve Russell

Recently Tiffany Joyce posted an article about determining correct exposure by reading histograms. She opened the article by questioning the need for the use of a hand held light meter. While I understand and agree with the point she was making, my reaction was more along the line of, “Wait a minute, I have a hand held light meter and find it useful under certain circumstances.” It’s not my most important piece of equipment, but when I need it, I’m really happy to have it.

After reading her article, I contacted Tiffany and during a back and forth exchange of thoughts and ideas through email we decided that I should write this article on the subject of hand held light meters, so here goes.

I would estimate that roughly 90% to 95% of the people that own cameras don’t need a hand held light meter. The features and functions built into the camera generally provide what the person taking the photograph needs to obtain an acceptable image. When the camera doesn’t expose the image properly the average person taking the photograph typically doesn’t know why and merely deletes the image. However, the other 5% to 10% that step up and purchase a DSLR, usually learn more about photography in general and demand more from their photographic efforts.

A photographer only has two variables to work with – light and time. Time is linear and mathematical. We understand time from early childhood and even the most inexperienced beginning photographer can quickly grasp the importance and operation of time in photography. Light, however, is a much more difficult concept and its understanding is critical to successful photography.

Different sources of light have different color temperatures. High color temperature light sources (like the natural outdoors light on an overcast day) are on the blue end of the light scale. Low color temperature light sources (like a candle flame or an incandescent light) are on the red end of the light scale. Since this isn’t an article on the color temperature of light or white balance settings I won’t go into greater detail but wanted to use this to emphasize the importance of fully understanding light.

A hand held light meter is normally used to measure incidence or ambient light – in other words, the light falling on the subject. The metering system in a camera measures reflective light, or the light being reflected off the subject into the camera. Most of the time there isn’t a measurable difference in the two readings – hand held light meter vs. in-camera meter. However, there are times where you will encounter difficult lighting situations and an incidence light metered reading would provide a more accurate exposure setting. In these cases a light meter can be quite useful.

Both metering tools provide a reading that is the correct exposure for 18% gray. In simple terms that means that both the meter and the camera are color and shade blind and try to read everything as gray. As a result, when you take a picture of a snow covered field the camera reads the snow as gray, underexposes the shot and renders the snow as gray in the resulting photograph. The hand held meter returns an exposure that properly exposes 18% gray as 18% gray and would properly expose the snow as white. This is because, unlike the in-camera meter, the hand held meter is reading the light falling on the subject, not the light reflected by the snow.

As Tiffany pointed out, reading and adjusting the histogram will solve the problem. However, I can pull my light meter out of my pocket, take a reading and take a photo faster than I can take a photo, switch to the histogram on my camera, adjust the exposure, recompose the picture in the view finder and take second photo.

The problem is reversed with black subjects. Let’s say you want to take a photo of an American Bison or a black bear. The head is black, the nose is black and the eyes are black. Remember that the in-camera meter will read the black as 18% gray and the photo will be overexposed. Again, the incidence light will give a correct reading

Now, put the two extremes together in a single photo and where do you acquire the exposure? While you have a number of choices, if you’re in the same lighting as your subject, the hand held light meter will give you the correct exposure. Or using Tiffany’s example of the professional wedding photographer who can hold the meter next to the group, the hand held provides the correct exposure without having to worry about white dresses, black tuxes and different skin colors. Again the histogram works, but the time spent reading a histogram could cause you to miss the perfect photo.

While writing this article, I got to this point and asked, “What if I’m wrong? What if all the advancements in technology, software and algorithms have actually compensated for these exposure issues?” A good question with a relatively easy answer. Why not test my beliefs on this subject. Unfortunately, I couldn’t find any snow and since I live in Florida I can’t even find snow in January. To substitute for the snow, I decided to photograph a white building in direct sunlight.

Photo by Steve Russell - click for larger image

For the first photo I used the manual setting on my camera because I wasn’t using a tripod and wanted to use a fast shutter speed of 1/500 seconds and an ISO of 100. The first photo was taken using the reading of f8 from my hand held light meter. Note that the building is white without being overexposed or blown out. Also the door is red and looks like it was painted by someone that would rather be in an air conditioned room.

Photo by Steve Russell - click for larger size

The second photo was taken with the camera set on Tv (shutter priority) at 1/500 seconds and an ISO of 100. The in-camera meter adjusted the aperture to f16 and I took the photo. Note that now the building appears gray in the photo, not the white my eye was seeing when I looked at the building.

There is also a situation where I believe a hand held meter is an absolute requirement for good photography. I’ve discussed this situation with a number of professional photographers and they all completely agreed. In a studio setting when you are using strobes, if you want to capture the best photos with the optimum lighting, you have to hold the meter near your subject (or where the subject will be) and fire the strobes to take a flash reading. Without using the hand held light meter, it will take a lot of trial and error to get the picture correct. I recognize that a photographer that works in the studio day-in and day-out probably knows that if the lights are in a certain position an f-stop of 5.6 is required and if the lights are moved to position B an f-stop of 8 would be required. However, for those of us that either use a make-shift studio or, in my case, a friend’s studio, the light meter saves a lot of time and disappointment.

As a footnote, in the middle of writing this article, my twenty-five year old Minolta light meter died. After a lot of research and discussion with other photographers, I purchased a Sekonic L-358 light meter as seen in the photo below. The new meter is the one I used to take the photos accompanying this article.

Light Meter - photo by Steve Russell

Photo credits (all): Steve Russell

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  • KaiWah

    I'm confused… Wouldn't the shot taken at f4 be twice as bright as the photo taken at f8? Could it be possible that those two settings got mixed up in the writing of this post or am I way off?

    Also, if you are shooting a predominantly white or light scene and you want to use Av or Tv why would you not just tell the camera to overexpose the scene by about a stop or so? In fact, sometimes if I have white in the scene I'll use spot metering on the white with a +1.3 reading on my reflective light meter and it's quite accurate. Black is just the opposite, just tell the camera you want to go -1 or so if you're in an automatic mode or meter off the black at -1.3. That's for my camera, your camera may be different a third of a stop or so, but it'll be close. Just know your equipment.

    Anyways, I really just was looking for clarification on the f4 vs f8 thing and got off on a tangent… apologies…

  • Steve Russell

    Okay, I'm embarrassed. KaiWah is correct. When writing the article I wanted to double check the aperture so I opened the photo in Adobe Bridge and then proceeded to look in the wrong place. It was taken with an f4 lens. The in-camera meter adjusted the aperture to f16. Very careless of me.

  • http://snerkology.wordpress.com/ Tiffany

    Good eyes, KaiWah! I corrected the article.

  • HenryPeach

    My Sekonic 508 saw daily use for years when I shot film. Most of my cameras didn't have light meters. Since switching to DSLRs I still carry it in my lighting bag, but it's only been used about a half dozen times in the same number of years. I was always a big fan of incident metering, but haven't found the switch to reflective metering to be troublesome.

  • Rmarshall100

    Good article. I have to ask Kaiwah why you would need to over or under expose to get white whites or black blacks rather than get the exposure right on to begin with? Does white or black exist in isolation from other colors or relative light levels in any good photograph?

  • KaiWah

    Rmarshall, As this post shows clearly the reflective meter in your camera is going to see all that white and try to turn it 18% gray therefore underexposing it by, in the example in the article, one stop. If you tell it to overexpose using the ev compensation function of your camera it knows that the scene is dominated by light colors and will go for a lighter tone with its automatic exposure. The inverse is true with dark scenes.

    I read a post (I wish I could find to link to it) when I was starting out that explained this pretty well. That post also made the point that if you know what your camera's reflective meter reads white or black at then if you have either of these colors in your scene you can spot meter off of that part of your frame, dial in an exposure of +1.3 for white or -1.3 for black (roughly, depends on your camera's meter… know your equipment) and shoot with confidence regardless of what else is in the scene. It made me much better at using the reflective light meter in my camera. There are times where this is a better option than running over to your subject with an incident light meter in hand. Like the example in the article about shooting a black bear. If you're standing in the same light as the bear then fine, but if you're in the shade and the bear is in the light it may be better to take a reflective reading off the bear in spot mode, manually dial in a reflective reading of -1.0 or -1.3, and shoot away. I for one don't want to run up to a black bear with my light meter in order to determine exposure…

    So knowing what black and/or white gives you in your camera's reflective meter can be a quick way to get very close to the proper exposure. You can get that bear shot and still have a nicely exposed frame. You can follow it up with the histogram method this article method suggests, but you should be very close already.

    So basically I'm trying to get around the problem illustrated in this article with a reflective light meter in tricky situations. Joe McNalley is super good at it. He almost always shoots Av and then “rides the exposure compensation”.

    Anyways, I hope that makes sense. It has worked well for me!

  • KaiWah

    Easy mistake to make. I've done it lots of times. I'm just glad I'm not totally losing it… :)

  • Fotofah

    Good article!

    One situation where the handheld meter excels is with more than one light in a studio with adjusting lighting ratios. I’d say that’s tough to adjust via just a histogram.

  • tsabarese

    I prefer a light meter to get actual readings at different areas of the framed composition. It's also indispensable when you're working with multiple lights in a studio situation. If you're interested in seeing how famous photographers light their images, take a peek at GuessTheLighting.com

  • JTM

    Interesting perspective on use of hand-held vs. camera technology, well written, and I learned a few things – can’t ask for more than that!

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