This is very likely to be your camera’s default setting and therefore the flash mode that your camera will be in when you first switch it on. In this mode, the camera decides whether there is enough light to take a picture without flash. If there isn’t, it will fire the flash and if there is, it won’t. It’s a set and forget option and the one most people will probably use most of the time.
Red eye is the effect you sometimes see in flash photographs where the pupil of someone’s eyes seems to glow bright red. It is caused by the fact that the built in flashgun is very close to the lens. That is why many cameras have a pop-up flash, to put more distance between the light and the lens.
Some cameras also have an anti-red eye flash mode. This switches on a steady light or fires successive flashes for a couple of seconds before taking the photograph. The idea is that all this light will make the pupil of the eye smaller and so minimise the effect. It sometimes works, but not always.
For example, if your subject is some distance away, it may not have a lot of effect. Even when it does work, it only makes the red eye smaller and you might still find it annoying. There are other downsides too. The actual photograph is not taken until the very last flash and that can be some considerable time after you press the shutter. Another thing is that it uses a lot of power and your batteries will drain much quicker.
Probably the easiest way to deal with red eye is to remove it from the photograph afterwards in a photo editing program because there is very little you can do about it when taking a picture using a built in flash. Probably the most effective technique is to ask your subject not to look straight at the camera but even that isn’t guaranteed to work 100% of the time.
This is where you start getting creative with your camera. If you have ever tried to take an indoor scene only to discover that the flash light totally ruined the atmosphere, then this is the setting you need. You also need to find something solid and stable to rest your camera on (unless you happen to have a tripod with you).
Most digital cameras are capable of taking exposures of several seconds (some up to around 30 seconds) so they don’t need to use the flash if nothing in the scene is moving. However, they do need to be absolutely still during the exposure, any movement at all will ruin the shot.
Even the movement of pressing the shutter button can be enough to spoil the picture but there is a way round this. Use the self timer. This is another function that exists on most cameras and, used in this situation, will eliminate any movement in even the longest exposure.
If you have ever seen press photographers or other professionals taking pictures of people outside you may have noticed that most of them are using flash, even outdoors in bright sunlight – why?
The technique is called fill-in flash and it has two effects. First of all it “lifts” the darker shadows on the face, which helps especially on very sunny days. Secondly, it creates a very flattering “catch light”, which is a tiny bright highlight in people’s eyes.
You can use this professional technique yourself by forcing your flash to fire even when there is enough light to take a picture without it. This is the “forced on” mode. It is especially useful when taking pictures of people against a very bright background, like the sky, for example.
In this situation, without the flash, people’s faces usually come out far too dark. If you increase the exposure to compensate, you often find that the sky simply “burns out” to a flat white with no detail. This does not make for a flattering image. Using fill-in flash will make the faces brighter without affecting the exposure of the sky and result in a much better photograph.
Flash exposure compensation
Some cameras will also allow you to adjust the brightness of the flash when in forced on mode. Ideally, you don’t want the flash to be bright enough to overcome the natural light, just bright enough to reduce the heavy shadows. If you have the option to adjust the flash, it is worth experimenting with different settings, especially when you first try this out.
Take the same shot over and over again changing only this flash exposure setting between each shot. Don’t make a judgement about which is best until you have compared the pictures on a good monitor or print. Most people find that the effect looks best when it is very subtle. That is, with the flash exposure compensation in the minus range.
If the flash setting is too bright then the shot can look very unnatural, but that doesn’t mean you won’t like it, everyone’s tastes are different. Once you have discovered the setting you like best, use this every time you switch to “forced on” mode.
Slow/second curtain flash
This setting is only likely to appear on more sophisticated digital cameras because it is a highly specialised way of using flash: but if your camera has it, this is what it’s for.
In this mode you will be taking a long exposure (possibly several seconds) and firing the flash during the exposure. When and why would you ever want to do this?
One situation might be if you were taking an indoor scene with something in the foreground that was in complete darkness. The flash would illuminate the foreground object whilst the long exposure would take care of the background. In this case you would control the lighting balance between foreground and background by adjusting the flash exposure compensation.
Another type of shot you can do is where a static object looks like it’s moving at high speed because there are “motion trails” coming out from behind it. This will only work if your camera can use “second curtain synchronisation”. If you try the technique described below, it will be easy to tell whether your camera has this or not.
You need to set up a shot with a long exposure and something moving in the frame during the shot. Without any flash, the moving object would just be a blur. By firing the flash, you also get a frozen image of the moving subject at the point when it fired. That’s where the second curtain sync comes into play.
If the flash fired at the beginning of the exposure (first curtain sync) then all the motion trails would be in front of the object and it would look like it was rapidly moving backwards. Using second curtain sync means the flash fires right at the end of the exposure and the motion trails will all be going in the right direction. It takes a bit of time to set up a shot like this, but if you get it right, the results can be spectacular.