Balancing Interior And Exterior Exposures
by William Lulow
We are often called upon to make images of interior spaces that have windows and include some exterior spaces as well. What’s the best way of combining exposures so that BOTH interior and exterior spaces are well exposed?
In the days of film, a photographer had to light the interior and then expose it to balance the exterior exposure. So, the procedure would most often involve taking a meter reading of the exterior exposure and setting the interior exposure’s aperture to be equal to it. Then, one would have to adjust the shutter speed to provide enough light for the interior. If you were shooting with flash, the speed of the flash was fairly constant. That’s why it wasn’t factored in to the overall exposure. If you slowed down your shutter speed, you were just letting some ambient light in to light up the interior, while keeping the aperture for both interior and exterior the same. Sometimes, you had to provide enough light from your flash heads to equal the exterior exposure if you wanted to stop any interior action. Also, you needed to balance any interior lights for daylight color temperature. None of these measures are really needed these days, but exposure balance is still necessary.
Whether you are shooting film or digitally, if you are trying to balance interior and exterior exposures, the interior will have to be lit. Here are some interesting images I made just with my digital camera:
This first image was made of the interior alone. I used the camera’s meter to arrive at the correct exposure, but the exterior is way overexposed.
Next, I made an exposure of the exterior also based on my camera’s meter reading. (I have my camera set on center/spot, so that I can get an accurate reading of anything I aim at). So, the exterior is properly exposed, but the interior is way under-exposed.
So, somewhere in between these two exposures you would figure the correct exposure for both interior and exterior would be, right? Well, it doesn’t work that way in practice. An exposure directly in between would still yield a dark interior and a much too light exterior.
My solution, in this case was to add some light to the interior with my camera’s built-in flash while keeping my exterior exposure just a bit brighter than the reading I got with my camera’s meter. I just made these images kind of off the cuff here to illustrate this article. Were I to photograph this interior/exterior as an assignment, I would have brought several lights in order to light up the interior more fully. I then would have gone through the same process of balancing the lens aperture for both interior and exterior exposures. But this kind of technique works in a pinch. You just have to think about getting the exposure for the exterior and then tweaking the interior exposure using a combination of your camera’s flash and shutter speed.