Using Flash Sync and Flash Exposure Modes

by Bill Jones

Many people never even use their flash sync, but this option is one of the many advantages of digital photography. In almost any DSLR camera, you will find flash sync settings that you most certainly should not ignore.

Flash sync can certainly turn good photography into amazing photography. Learning about flash sync is not something that you should put off. Your camera also includes flash exposure modes that are a must for combining flash lighting with exposure for a better metered image.

Just what is Flash Sync?

There are many reasons why most people do not even use flash sync. Many people simply do not realize it is an option. Some people may find the sync in their camera, but they may have no idea what it does. Others may think that flash sync actually is not needed for that many images. However, the more you learn about this technology, the more you will find that you can use it in digital photography. The first step to properly using flash sync will be to understand just what it is.

In essence, flash sync has to do with when the flash actually fires during the exposure. It is possible to change when the flash fires for various effects for the image. At times, using flash sync is a good way to compensate for certain difficult lighting situations. At other times, you may want to use flash sync to create specific artistic or dramatic effects in your photography.

The Three Flash Sync Settings

On any digital camera, you are going to have a choice of flash sync settings. You need to understand just what each of these settings is and you will need to know how they can be used in digital photography for various lighting situations. Below, you will find a breakdown of the three settings so that you can better understand their purpose.

Front Sync (Front Curtain Sync)
This is when the flash will fire at the very beginning of the image exposure and this is generally the default sync for a camera. However, this is not a sync that you will want to use in many situations. If the subject is moving, you could end up with a problem. When the flash fires at the beginning, the shutter speed stays open and your subject moves, you will end up with something called ghosting. The image will appear as if there is a ghost in front of the subject. It will be blurry and streaky. Generally, you do not want to use front sync for moving subjects unless you are doing something artistic.

Rear Sync (Rear Curtain Sync)
With this type of sync, the flash will fire at the end of the exposure. If the subject is moving, you will still end up with ghosting, but it will be a different kind of ghosting. In this type of situation, you will have a sharper subject with slight ghosting and what looks like streaks behind the subject. In many situations, this is an excellent way to translate motion. However, if you want a clear, crisp image, you will not get it with rear flash.

Slow Sync
With this mode, your camera will do two things. It will slow down the shutter speed deliberately and it will slow down the flash. What does this accomplish? Often, there are background details that will not be illuminated by the flash in most situations. When you want those details to be in focus, you can use this sync. The slow sync will slow the shutter speed enough to make sure light gets to those background details. To use slow sync, you must keep the camera very still and you will not want to use it for subjects in motion.

Exposure and Flash Exposure Modes

Camera exposure has already been discussed and you may have a good idea of how to use various exposure settings in digital photography. However, you also need to know more about flash exposure. These modes will be able to combine all of the elements of exposure along with the elements of the flash and the flash sync to create a better metered image. Your camera will include several different flash exposure modes that you will need to know how to use. They may go by different “techie” sounding names, but the exposure modes available in your camera include the following four.

TTL (through the lens)
This type of metering measures the exposure through the camera lens to set the flash. This method is useful in most situations. However, in some situations where light bounces strongly off the subject, this mode may lead to washed out images.

Pre-Flash
This method of flash metering works by the camera actually firing a flash before the image is taken. The camera uses the metering information of that pre-flash to set the exposure. This is useful when you are using certain elements with a flash like a diffuser or a darkener that could otherwise confuse the camera.
Integrated
This method also makes use of a pre-flash, but the camera actually integrates the information provided into the exposure before it ever takes a picture. With this method, the camera will be able to avoid washed out images in which light bounces off the subject.

Manual
In this method, you will be in full control. You will decide the level of strength that the flash uses and you will set the exposure. This method can take a great deal of patience and does include a learning curve. Your digital photography will take longer and you will need to be prepared for this. This method will not be the best option when you need to take pictures quickly.

When you will be using a flash in your digital photography, it is vital that you learn how to use flash sync as well as flash exposure settings. Through these two tools, you can gain much more control over your camera, your flash and your digital photography overall.