Slow Sync Flash Photography

When you are shooting in a low light condition, you have a couple of options to set the exposure correctly. One is to use a slower shutter speed and the other one is to use an external flash unit as a light source. When you use the slower shutter speed, you will be able to collect enough ambient light to get the proper exposure. This technique works very well when you are shooting non-moving subjects such as a statue, trees, buildings, landscape etc. But there is a chance of getting a blurry image when you are shooting moving subjects with the long exposure setting. On the other hand, when you use en external flash unit and let your camera choose an appropriate settings automatically, camera normally sets faster shutter speed because it detects there is a presence of an external flash unit to compensate the exposure. Now, when you shoot with that camera settings, you will get the well exposed subject but you will also get the dark background because the camera sensor didn't get enough time to collect the ambient light from the environment.

An example of slow sync flash

It's common that the ambient light will be much warmer than the electronic flash lights . If you want the two sources to match, you may want to use a warming filter on the flash. That can be done with a gel if you are using an external flash unit like the SB-600, SB-700, SB-800 or SB-900.

This is the situation where the slow sync flash comes handy. It combines both techniques discussed above and gives the better result. Slow sync flash is the perfect choice for low light photography specially if you are shooting portrait or other moving subjects. This technique is supported by most of the DSLRs which tells your camera to shoot with both slower shutter speed (longer shutter opening time) as well as firing the flash. When you are using slow sync flash, it fires the flash briefly to light the foreground subject and capture the ambient light to reveal more details in the background. With this technique, you will get the properly exposed subject and also be able to collect the ambient light from the environment to get well exposed background scene. If you have noticed "night mode" or "night portrait mode" available in your camera, they use the same technique but will give less control to the photographer. If you need more control over the shutter speed or flash power, you have to use the Manual Mode (M).

An example of slow sync flash

When we talk about slow sync flash, there are couple of slow sync flash techniques we have to discuss. And they are - front curtain sync flash (also known as the first curtain sync flash) and the rear curtain sync flash (also known as the second curtain sync flash). Both front curtain flash and the rear curtain flash techniques can be used for moving subjects when there is a mix of the ambient light and the flash light to get the motion blur effect.

1. Front Curtain Sync Flash

The standard slow sync mode is the front curtain sync mode. This mode tells the camera to fire the flash at the beginning of the exposure and then keeps the shutter open for the ambient light exposure. That means when you press the shutter release button, the flash fires immediately which freezes the motion of the moving subject and then the shutter will remain open afterward for the duration of the shutter speed and captures the ambient light.

2. Rear Curtain Sync Flash

This mode tells the camera to fire the flash at the end of the exposure. That means when you press the shutter release button, camera opens up the shutter and starts collecting the ambient light and just before closing the shutter, the flash will be fired to light up and freezes the main subject.

Rear Curtain Sync Example (Image Credit : Todd Klassy)

Rear Curtain Sync Example : When the card was moving from the top left corner to the bottom right corner, rear curtain sync flash gave that nice trailing effects of traveling path while giving a clear and frozen shot of the card at the end.

Both techniques look the same but they both have different effects when properly applied. Usually, you will find sports photographers using the rear curtain sync flash to freeze the player and get the nice motion blur effect behind the player.

Lets take another slow sync flash photography example of "moving car on the road".

Front curtain Flash : When you press the shutter release button, shutter opens up and the flash will be fired immediately which freezes the motion of the car. While the car is continuously moving, shutter will be closed and end the exposure. Because of the less light available at the end of the exposure, there is a less light motion blur in front of the car.

Rear Curtain Flash : When you press the shutter release button, shutter opens up until the exposure time and because of the less available light, you would get a less light motion blur at the beginning. While the car is still moving and at the end of the exposure, flash will be fired which freezes the motion of the car and then the shutter will be closed. In this case, the motion blur is behind the car, as it should be.

If you want to learn more about the flash photography and other available flash modes with more examples, please read my latest blog - “Understanding Flash Sync Modes”.

Nikon SB-700 Speedlight Review

I am a big fan of Nikon CLS technology and Nikon impressed me once again with it’s newly announced small and compact but powerful lighting system, SB-700. This flash unit lives up to the Nikon legacy. I always repeat the fact that photography is all about adjusting the composition and the lights. To support this fact, most of the DSLRs come with a built-in flash but the features they provide is very limited. That's why it is almost necessary to have an external flash unit which can provide creative control over any given lighting condition. If you are using a Nikon DSLR, you have many options to choose from; SB-R200, SB-400, SB-600, SB-700, SB-800 or SB-900. The Nikon Speedlight SB-700 is the newest addition to the Nikon flash lineup and can be considered as a replacement for SB-600. I was using a SB-600, which worked fine, but the SB-700 was just a great upgrade. Let’s talk briefly about this new gadget from the Nikon.

Nikon’s SB-700 is a compact flash unit but filled with features that SB-600 lacks and some of the features are inherited from more professional flash unit like SB-900. The built and the design of the unit looks professional, supports commander mode, capable of multi-step auto zoom up to 120 mm. It is designed with high-speed recycling time of 2.5 seconds with the NiMH batteries and 3 seconds with the Alkaline batteries. The built size of Nikon SB-700 (2.8 × 5.0 × 4.1 in) is a bit larger than SB-600 but smaller than SB-900 unit. However, it resembles more with SB-900 and shares some of the features and the control layout with SB-900 as well. The interface on the SB-700 is much more straight forward than the SB-600 which requires you to push two buttons at the same time to get into the menu items and configure the flash unit. The SB-700 is a much easier and faster unit to setup and has more features than the SB-600.

SB-700 is redesigned with the interactive control and very easy to setup and use. As I mentioned before, some of it's features and even controls are borrowed from SB-900. It has a nice LCD screen on the back and includes two mode switches on the left and the right side of the LCD screen which allow user to change modes without navigating through all the menu items. The SB-700 comes with the incandescent and the fluorescent filters for the color balance when shooting indoors. The SB-700 automatically detects the type of filters in use and adjusts the settings accordingly. It also comes with a built-in bounce card that can be used for the bounce flash effects and the diffusor to soften the intensity of lights.

Nikon Speedlight SB-700

Features & Performance

1. Automatically senses the FX or the DX-Format camera in use and optimizes the light distribution.

2. Automatically identifies the mounted hard type color filters and adjusts the camera white-balance.

3. Works with the Nikon’s i-TTL (intelligent through-the-lens) metering system. This system works by firing a series of flash bursts to assist the camera in analyzing the scene. The camera’s metering system then processes this information and sends it back to the flash unit, balancing the flash output with the ambient light.

4. Using the simple slider switch on the back of the SB-700, you can optimize the light quality by selecting the Standard for general illumination, Center-weighted for portraits or Even, for groups or interiors.

5. Most of the newer entry level Nikon DSLRs do not have a commander mode to remotely control the flash Off Camera. And in that case, SB-700 can be used as a commander flash unit as well to control multiple wireless flash units.

6. SB-700 has a built-in thermal cut-out detection feature to prevent it getting damage from overheating. It works by extending the recycling time when SB-700 detects the heat build-up.

7. Flash Value (FV) Lock feature locks in a specific flash output on the main subject, regardless of the aperture, composition or the lens’ zoom position.

All in all, I highly recommend this flash over the SB-600. I wanted to get the SB-900 but its just too big and heavy for my needs and also couldn't justify the additional cost as well.

Direct Flash Light Vs Bounce Flash Light

Good lighting is a key to create a good photograph. It is very challenging aspects of photography as well. It takes knowledge, many years of practice and experiment with the different settings and lighting environment to get master on proper lighting. Some photographers like natural light and others like to use studio strobe, some photographers love one kind of light effect and others prefer different setting. So, it's very hard to say which one is the best lighting strategy and the only way to find out is to experiment yourself and find out which works best for you. I am still a beginner and not in a position to judge anyone’s technique or favor one technique over the other. In my view, it all depends on the shooting environment and what kind of effect you want to get in your photograph. I have seen many photographers divided over the argument of using Direct flash vs Bounce flash. There are some cases you may want to use the direct flash and sometimes you don't want to use the direct flash at all. It also depends on under what situation you are composing the photograph. Most of the time, photographers do not want to use direct flash light for portrait shots because it may produce glare highlights and shiny foreheads due to the light coming out of the powerful source from the short distance which hits directly to the subject. In that case, there are many ways you can soften the light and give more natural look to the photographs.

Index Card Diffuser

Photographers are practicing different techniques to soften the light which helps to reduce the shadows due to harsh light. Mainly, they use either flash diffuser or bouncing the flash lights using any bouncer (ceiling or any reflector). If you do not have the flash diffuser, you can make your own by using a small indexing card over the flash unit and tape it so that it bounces the light to the ceiling and reduce its intensity and producing soft and natural effect to the photographs. But when using bouncing light, you have to be very careful about the surface from which you are bouncing the light because the bounced light will pickup the color of that bouncing surface which directly affects the photograph.

While preparing for this post, I took two shots very quickly. One with the direct flash lights and the other using the bouncing light. In both cases I used off camera flash Nikon SB-600 and fired it from angle. First, I applied direct flash to the subject and the second time I bounced the flash light using the white ceiling surface over my head.

Effect Of Direct Light Source

Effect Of Bouncing Light Source

In this particular situation, I think bouncing the light worked better than hitting the subject with the direct flash light. When the light was bounced, its intensity was decreased and soften the light on the subject. Also, the bounced lights coming from the various angles helped to remove the shadow of the subject.

In my opinion and generally speaking, photographs look more natural with the soft bouncing light than with the direct harsh light producing unpleasant highlights and shadows. But if you do have any different ideas or thoughts, please feel free to share it with us.