Why does negative flash adjustment lead to weird, orange pictures?

Question

I try to shoot with available light as often as possible, but sometimes I just have to pull out the built-in flash on my Panasonic GH3. I don’t like the “rabbit in the headlights” look of the photos taken with the built-in flash, so I tried to dial the flash down a bit (–2 EV). The idea was that there’s not going to be so much hard light from the flash and I’ll just get the small light boost needed to drop the ISO down to acceptable numbers. The trouble is that the photos taken with the adjusted built-in flash come out strange:

It’s ISO 800, f/2.8, 1/125 with built-in flash stepped down by 2 EV. I don’t like the orange tint and the “flatness” of the picture. (Hopefully it’s clear what I find wrong with the picture, it’s subjective. If it’s not clear, I’ll try to shoot a better one.)

Is this a camera deficiency, is this to be expected with a built-in flash, can I do something about it?

Answer 1

Camera flashes are generally balanced for daylight equivalent color temperature. That means that the white balance used with flash expects a much bluer light than typical indoor lighting. If your flash is providing most of the light, that's perfect. But when it isn't, the color temperature of the ambient light is dominant.

That's what's causing the orange color here. If your camera lets you set the white balance manually (or even force it to auto), that will help that problem. It's difficult, though, especially when parts of the scene are lit more by the flash and other parts more by the ambient light, because then there is no single right answer for the whole image (see more on this at How do I take portrait photo with flash and good ambient light as background?). In some cases, as @heropup suggests, you can put a colored gel on the flash so that it comes out the same coloras the ambient — see Using Gels to Correct Light @ Strobist for a great article on the topic.

As for "flat", that's just what you get with direct, on camera flash. There aren't any shadows to give depth cues. This situation (award ceremony in a school gym?) never lends itself to great portraits, or even great documentary photography. My advice is to take the snapshot, and then if you want set up another shot layer in better lighting.

Answer 2

You can correct for the orange tint by adjusting the white balance of the image in post, but this creates another problem, because the color temperature of the flash is different than the ambient lighting. Doing such a correction would make the light contribution from the flash look even more blue than it already is, so highlights on the face from the flash will look blue compared to the rest of the image.

There are a handful of ways to address this mismatch: gel the flash; increase the flash power; bounce the flash; or don't use flash. If you put a colored gel that matches the color of the ambient light in front of the flash, then a custom white balance will work. If you increase flash power relative to the ambient light level, then you will balance for the subject illumination from the flash, and let the ambient go darker, and stay orange. But for a pop-up flash, neither of these are really ideal. If you go without flash entirely, you can get a good color balance but the subject illumination may be too dark.

Moving the flash off camera and putting a gel on it to match the ambient light is the best overall solution. If you can bounce the flash, then that could work very well too, but that requires a way to bounce the light, which depends on your equipment and your relation to objects in the room. I frequently do this in a pinch--bounce off a ceiling or wall, plus some flash exposure compensation. But for a pop-up flash, you probably won't have the power output or the ability to direct the light to do it.

Answer 3

What you get is a bad case of mixed light. You have the very cold (blue) light of the flash mixed with the very warm (yellow) light of the indoor lighting.

When mixed light is used in photography, one of the light temperatures can be chosen as natural, or different parts of the scene can be processed with different white balance, and then put together.

Neither works in your case, as you have a mix of the lights all over the subject. Some parts of the face has more of the flash light, and some parts have more of the indoor lighting.

If you want to use flash and indoor lighting together, then you either need a color filter on the flash to match the color temperature with the other light, or you need to use more flash so that the indoor lighting only contributes substantially to the shadows.

The flatness of the image is because most of the light (at least in the hightlights) comes from the straight on built-in flash. To get good depth you would need light from at least two directions (stage lighting), or light from an exact angle to the side to produce shadows in the right places (e.g. Rembrandt lighting).