Recently we reviewed how to find the power of your sensor in the darkness of a lens cap, as well as injecting skin tones into your test. In part three, we will test your camera’s latitude. This is one of the most important tests that you can perform because over exposing is a very subjective and personal artistic choice. This test will show you how far you can push the over and under exposing of your camera and what looks good to your eye. I suggest throwing the vector scopes, histograms and the wave forms away. You need to train your eye and not use those devices as crutches.
Taking Your Image to Extremes
Let’s begin with over exposing. This test shows you how it handles the highlights. Set up your grey card and color chart on the same focal plan as your model. Frame a shot that is a medium size frame so that the charts are just in the left and right sides of the frame. There are many ways to light this test. We used a very frontal light source that was very bright so we could start at a high f-stop and then work our way down in 1/3 stop increments.
We stayed at the native ISO of the Canon 1DC, which was 400 ISO. This gives you the most dynamic range. We opened the lens up a 1/3 stop each time we rolled. 1/3 increments is essential. 1/2 stop increments was the standard with film stocks, but with digital, 1/3 of a stop feels more like a 1/2 stop on film. Take this test as far as you can.
*Disclosure: We wanted to see if we could bring the image back from overexposure by compensating with color correction at stops +1 2/3 and again at +3.
Taking Your Image into Muddy Waters
Our second direction is to under expose the sensor. This shows you immediately how far you can take the shadows. Set up your grey card and color chart on the same focal plan as your model. Frame a shot that is a medium size frame so that the charts are just in the left and right sides of the frame. We used the same frontal light source and started the under exposing process by going down in 1/3 stop increments again. Immediately you can see that the 1DC really needs light. With the 5D sensor, we needed to starve it of light to get it to look filmic. With the 1DC, it reacted much like film. This camera loves light. I would always over expose my negative a 1/2 of a stop across the board. The 1DC reacted the same way. As you go down, you can quickly see you enter muddy waters. The image starts to fall apart and get very muddy, loses snap, vitality.
*Disclosure: We wanted to see if we could bring the image back from under exposure by compensating with color correction at stops -1 and again at -3. This shows that the camera really needs light and reacts more like film.
Testing the Downside
When I do these latitude tests, I also like to see how the fill levels react to a model’s face. This is so important. One person’s moody fill level is another person’s flat fill level.
I set the model up with a side light so that I can really see when that detail on the shadow side looks the best. When I was lighting Eli, I loved the look on her face at -2 2/3 stops down. For a guy, I would probably be around -3 1/3 stops down. For intense mood, I thought -4 stops looked bangin’ as well.
You can start your test with the key and fill at the same level so that your model’s face is flat as a brick. Then decrease your fill in 1/3 stop increments again. Take it as far as you can go.
In a future post, we will discuss when you take your camera on location and see how your storyteller performs in different lighting conditions.