How do I reproduce this dark background on this photo?

Question

I was trying to take some photos of flowers, when I managed to snap the following photo:

This is the jpeg the camera made. The foreground is bright, while the background is dark. Creating the dark background was a good kind of accident, I think. How can I reproduce this effect on future photos?

I know I can do this with flash or sunlight, but it was a cloudy day, and I did not use flash. The flower appeared to not be particularly bright to my human eye over the background. How did I achieve this effect anyway?

ISO 200, shutter time 1/950, aperture unknown for certain but presumably f/0.95, 1.5x crop sensor camera.

Answer 1

Lighting for shots such as this one is not about absolute lighting levels, it is about lighting ratios. The 'dark' parts of the picture don't need to be in absolute darkness. They just need to be less bright than the bright parts of the scene by enough to make them dark by controlling exposure.

As long as the part of the scene you want illuminated is lit brightly enough compared to the part you don't want to be bright and exposure is set appropriately you'll get the effect you are looking for.

The flower appeared to not be particularly bright to my human eye over the background. How did I achieve this effect anyway?

Even though you didn't notice it at the time, the flower is, in fact, much brighter than the background. Our eye/brain systems aren't very good at seeing such differences. We're more wired to do the opposite. That is, our vision tends to create a world where the differences between bright and dark areas are less than they actually are. That's why many people take a photo of something that is half in direct sunlight and half in the shade and then are surprised by the difference between the shaded and unshaded parts of the shot.

This image was taken in fairly pedestrian indoor lighting levels. There was a black curtain about 15 feet behind the subject. A fairly hot flash was illuminating the subject at about a 45° angle to lower camera left.

_{ISO 100, f/4, 1/80 second. No overall brightness adjustments in post. Contrast was increased +2, but the shadows were also brightened +2 and the highlights pulled back -3}

Here is the wider scene at the same exposure setting for a test shot before the curtain was adjusted to cover the background behind the subject. The ambient light is underexposed by about 4 stops.

Here's an uncropped version of the first image above with the exposure pushed three stops in the raw conversion. At that point the house lights had been cut, but the overhead stage lights were the same as in the test shot. You can see the flash at lower left is spilling onto the curtain a bit, but the difference between the brightness of the curtain and the face is enough to leave the curtain very dark at the selected exposure settings as seen in the crop above.

When you want the background to be dark the key is to get enough distance between your subject and the background so that light illuminating the parts of the scene you want to be bright does not spill onto the background you want to be darker. The same is true of walls off to camera left and right: they need to be far enough away and non-reflective enough that light won't bounce off of them and back into the scene.

With a dark background you can flag your off camera flash to reduce light spilling onto the background if you need to.

For how this works out with a dark background, please see: If I want to shoot darker shots, is it better to increase the lighting and then darken in post to retain clarity? Note that the dark areas in the photo can be much brighter than they look in the image, exposure just has to be set to 'kill the ambient' and the parts you want to be bright have to be lit brightly enough to still be bright at that reduced exposure value.

For another question that deals with a lighter background, please see: How to get this particular black and white look?

Answer 2

There is no magic, it's just a matter of setting your exposure to obtain the result you want, which can be done in several ways such as by using exposure compensation (in auto exposure modes), dialing your own exposure settings (in manual mode), or dragging the "Exposure" slider leftwards in postprocessing (assuming you didn't blow up your highlights at shooting time).

In a comment, you say you were using spot metering and had negative exposure compensation, both of which work in that direction. Remember that in all modes except Manual, the camera will use exposure settings that will make the average brightness value of the image middle gray. Here, since most of the image is background, that wouldn't have worked: you would have had a middle gray background and a very bright flower. Using spot metering tells the camera to only consider a small area of the image (usually at the center) and make that area middle gray, disregarding the rest. Thus if the spot is on the flower, you get a middle gray flower and a dark background.

And using negative exposure compensation compounds this by making everything even darker.