Dean Johnson
www.deanjohnsonphoto.com

"Digital Exposure"

Having shot mostly digital now for a few years I feel that I’ve overcome some of the challenges that face most photographers when it comes to getting proper exposure on their digital images. I think I’ve streamlined the process down to a really simple process that is also very effective.
I am often asked about how I meter, and I often see photos that could have been better if more care was taken in getting proper exposure, so I thought I’d share what I’ve learned over the last few years.

I think it’s important to understand that digital cameras are designed to take low contrast images. By that I mean that they are built and designed to gather as much information as possible when capturing an image. They are designed to record as much detail as possible in the blacks as well as the whites. That’s why in most cases the captured image will appear a little flat and dull. It’s then up to the photographer to decide what the image should look like and set the blacks (shadows) and the whites (highlights) using image editing software such as PhotoShop. In certain situations (really high contrast lighting) very little, if any, tweaking to the contrast needs to be done to the image. But in most cases images will benefit greatly by a simple adjustment to the contrast. I sometimes refer to this as “finishing” an image because in my mind an image isn’t done unless the contrast is set. So when one over, or under, exposes an image they are restricting the amount of information that the camera can record. Whether you’re shooting RAW or JPEG it’s a good idea to record as much information as possible at the moment of capture. A RAW file will give one a little more leeway, as it maintains more information on capture, but it too has it’s limitations and colors and tones will suffer if not exposed properly.

Before we go any further here I feel it’s necessary that I explain what I mean by “proper” exposure. Proper exposure means to expose the subject properly to achieve the look you want in the final image. There are times when you may want to over-expose your subject, at least it’s over-exposed according to what the meter is telling you, in order to get what you want. For example, maybe you are doing headshots and want to burn-out some of the detail in the face in order to get that commercial headshot look. In this case you’ll want to over-expose a bit. But really if that’s what you want then it’s really not over-exposed at all, it’s exposed properly.
A meter, handheld or in camera, is designed to give “correct” exposures based on the subject being 18% reflective. Not all subjects are 18% reflective nor do you always want to expose for 18% reflectivity.

When I first started shooting digital I read a few books and many magazine articles and in so doing was warned numerous times about not overexposing. I heard things like “be careful not to overexpose because you’ll lose detail in the highlights” and “expose for the highlights” etc. As a result of all those warnings my images were ending up underexposed. And while it’s true that if you overexpose highlights you’ll lose detail it’s also true that if you underexpose you’ll lose details in the shadows. The same principal holds true for both highlights and shadows, or better said, the blacks and the whites. Further, if you underexpose the main subject for fear of losing detail in the highlights, your colors (midtones) are going to suffer. The key is to expose for the subject. There are many scenes that you’ll photograph that will have highlights in them and if you’re paranoid about overexposing them you’ll likely end up underexposing the midtones, which is generally where your main subject will be...in the midtones.
You’ll see what I mean in the examples below but for now let’s discuss how I go about determining exposures.

Before I get into describing my metering methods, I should say that this may or may not appeal to you. It works for me but I don’t pretend it’s the only way or even the best way.

I generally use a digital target for setting white balance and to get my base exposure. This is the product I use; http://www.photovisionvideo.com/
I just have the model hold this target while I take photos of it until I get a good reading, one that has all three spikes on the histogram (one each for the shadows, midtones and highlights) centered evenly. I then use that capture to set my color balance. This will give a fairly neutral white balance and if warmer tones are desired I can add that in Photoshop.
Now, as with any meter, this is designed to give you exposures based on 18% reflectivity. You may, or may not, want to adjust exposure a bit based on your subject. A dark-skinned African American may need a bit more exposure and a light-skinned Caucasian may need less exposure, depending on how you want to record them. Until you get a good understanding of how to use exposure to get certain results I suggest not wandering too far from the base exposure that your target gives you. Try to stay within one stop for now. This will give you the best results for skin tones and vivid colors, and will give you the most detail throughout the range of tones.

This image was shot after hours at the Peoria Supershoots 2007, and after the shoot was done I was asked by another photographer if he could see the histogram so I showed it to him. And I’ll use that as an example here to help illustrate the process I go through in order to determine exposures. I think you’ll find it amazingly simple.
Model is Roberta and Make-up and Styling was done by Kate Carroll.
This is the image as it came out of the camera. Shot at 1/40th sec. at f/2.8.

This is the image with the histogram displayed. Note that this image has quite a bit of black in it and those blacks show up on the left side of the histogram. Also note there are few whites in this photo, mostly from the specular highlights on the couch, and that’s why there aren’t a lot of pixels towards the right side of the histogram.

And finally this is the “finished” photo after levels, curves and colors were adjusted.

Here’s the process I took to get the exposures. While Roberta was getting her make-up done I started setting up the lights and did some metering. Basically I meter by taking photos and then viewing the histogram and adjusting from there. And in this case I took photos of the set before Roberta got there and adjusted the output of the light on the background until it was recording as I wanted it to. I no longer use a handheld meter when shooting digital, I’ve found that there’s no need for it. To me it’s just another gadget that needs batteries, which are always dead! And it’s one more thing that one has to remember to pack in your bag. Whether it’s ambient light or strobe, or a mix of the two, I use the camera and the histogram to determine exposures. I no longer have to worry about losing the meter or having dead batteries, if I have my camera I can shoot in whatever situation I’m in. Another advantage to using the camera to meter is that you no longer have to guess if something is 18% reflective or how much to compensate for that. You take a photo of part of the scene, in this case the setting, or background, and then by looking at the histogram you know exactly how it's exposed and how it “looks”. You can tell exactly how the blacks, whites and midtones are exposed.

I had decided that I wanted this set to look warm and light. So I started the lighting setup with one strobe to camera left and slightly behind where the model would be posing. And I used a gold umbrella to give it the warm tones. I took photos of the set, with just that one light going off, until I got it to record as I wanted it. By just looking at the histogram I could actually see how the various tones were being exposed.
I then added another strobe with a silver umbrella off to camera right and slightly behind the models position. This light would be providing some rim lighting (and hair light) on the model and also some accent lighting on the set, mainly the couch. As Roberta wasn’t on set yet I just took a few photos of the set with that second light now added and adjusted it until I got some highlights from the couch. Again, no meter, just using the histogram and adjusting light output until I got what I wanted.

I had already determined that I wanted to shoot this set with a wide aperture so as to throw the background out of focus. I decided to shoot it at f/2.8 and just set the output of the strobes accordingly.
Had this been shot at f/5.6 or smaller, I think the busy background would have started coming into focus and would then become quite distracting.
Once Roberta arrived on set, it was just a simple matter of setting up the main light, again with an umbrella, but this one was white, and adjusting it’s output until she was properly lit. In order to do that I just began by giving her my digital target and instructing her to hold it under her chin and then I took photos of the target until I got spikes (representing the blacks, white and midtones) on the histogram centered. That gave me my base exposure and also my target for setting the custom white balance. You’ll see in photo one (above) that the custom white balance setting that I used her gave a fairly neutral balance to her skin tones. The tones were warmed up a bit in post-processing as you can see in photo 3 (above).
In a nutshell, all I did to get my exposure figured out was take images of various parts of the scene and set the output of the lights to get those various parts exposed the way I wanted them to be.

In the photo below you’ll see what might be a better example of exposing for your subject. In this case, I was shooting an African American against white window shades, had I just exposed for the whole scene I likely would have underexposed it due to all the white in the scene.
So what I did in this case was to just take a tight photo of her face only and adjusted aperture/shutter speed until I got the exposure on her face where I wanted it. I didn’t really care if the window shades got blown out...I didn’t need any detail in them. Had I still been listening to everyone saying “don’t blow out the highlights” this image would have been severely underexposed. You really don’t need to be concerned about blowing out highlights unless they happen to be on your subject....don’t worry so much about blowing out highlights on the background or set. And the same goes for the blacks in the scene, don’t worry about trying to keep detail in dark parts of the image unless they are important to presenting the subject the way you want to.
Here’s the photo. Lit with window light and one reflector to camera right.
Model: Gloria MU by model.

And here’s the image with the histogram in place.

Now here’s that same photo but this time I selected the face only to represent the tight shot that I took in order to set my exposure.

Note that on this selection of the face only there are no blown out highlights. The blacks, from her hair on the shadow side, are a bit tight up against the left edge of the histogram and they could have used a little more exposure. But had I done that her skin tones would have started to get blown out. I was more concerned about not losing detail on her skin then I was with losing detail in her hair. The important thing here was to maintain detail in her face, both on the light side and the dark side, and this exposure setting struck a good balance for what I wanted to do. By the way, this was shot at 1/125th sec. at F/2.8.

Your camera came with a histogram for a reason, you should use it to full advantage. I think using it, rather then a handheld meter, to set exposures is about the simplest, and really the most accurate, way to determine exposures. Give it a try, maybe you’ll like it. If you decide to stick with using handheld meters just be sure not to ever forget it and don’t let the batteries go dead! You’ll be lost should you ever find yourself without it.

Dean Johnson

See more of Dean Johnson's Photography here.