How to Use a Flash – Top 6 Tips & Tricks

Last Updated: May 23, 2021

Written by

Light is a major component in photography; some photographers even claim it’s the most important element of a photograph. I always try to use the natural or available light where possible, but if the available light is not enough or not good, you may need to add some light – by using a flash.

The problem with light is that smaller the light source, the harsher the light is. Such light produces equally harsh shadows, which look pretty unpleasant.

The sun, for example, is a small light source. Small? Yes, given the distance to earth it’s a small light source. That’s why direct sunlight produces harsh shadows that are not very flattering, such as in the picture below.

Portrait of Michael Kummer with harsh shadows due to direct sunlight

The same issue applies to on-camera or pop-up flashes, which light the subject straight on. It just doesn’t look pretty.

Before I give you some tips on how to get the most out of your flash, let me tell you how not to use a flash.

1. Don’t Try To Light Distant Objects

A couple of years ago, when I knew nothing about photography, I was on a business trip to Dubai. One night we went out for dinner and I had a Sony Point & Shoot camera with me. When we got out of the restaurant I tried to take a picture of Dubai’s skyline at night. So I switched the camera to the “Nightscape” setting and fired away. The resulting picture was blurry. So I figured that maybe some flash would help light up the scene and prevent the picture from being blurry. The result was even worse – the foreground was harshly lit by the flash and the skyline was very dark and barely visible.

What happened? Well, each flash has a so-called Guide Number, which determines its reach (in feet or meters).
The built-in flash of a Nikon D3100*, for example, has a guide number of 39. Divide that number by the aperture of the lens you are using, and you have the maximum distance (at ISO 100) your flash can reach. So by increasing the ISO (light sensitivity) or using a wider aperture (smaller f-number = let more light in), you increase the reach of your flash.

Example: A Nikon D3100 with a lens set to aperture f/5.6 gives you about seven ft (or 2m) of reach at ISO 100.

Consequently trying to light a skyline that is 1 mile (or 1.6 kilometers) away, with an on-camera flash is not going to work.

Note: To take a picture of a skyline at night you have to put the camera on a tripod and use a self-timer or cable release to prevent any camera shake and thus blur. Even the slightest movement at such a long shutter speed (seconds) will result in a blurry picture.

San Francisco Nightscape with Moon

Another example of “that’s not gonna work” is when people try to take flash pictures in a concert while being 300ft away from the stage. Next time you see that, remember this post.

2. Don’t Take Flash Pictures In Front Of Reflective Surfaces

If you stand in front of glass or a mirror you may not want to use a flash either. I have seen people in aquariums trying to make up for the lack of available light by using a flash to photograph an animal behind glass. All you’re going to see in the photograph is a bright spot caused by the reflection of your flash. The same applies to mirrors for obvious reasons.
Even if your intention is not to take a flash photograph of a subject behind glass, watch out for any glass or mirror in the background, behind your subject, that could ruin the shot with a reflection resulting in a bright spot in your picture.

Now that we have determined how not to use the flash let’s get into getting the most out of your flash:

3. Avoid Lighting Your Subject Straight On

We have already determined that using an on-camera flash produces harsh light. The other issue with on-camera flash is that it lights the subject straight on. That produces a very flat image, which lacks perspective and dimension. The solution is to get an external flash (for example a Nikon SB-700 Speedlight*) and use it off-camera.
If your camera doesn’t have a built-in commander mode, such as the Nikon D5000*, the cheapest option is to get an SC-29 c*able* that connects your camera to the flash. Alternatively, you can go wireless by buying an SU-800 transmitter* or the Canon equivalent.
If your camera has a built-in commander mode, such as the D7000, you can control your flash wirelessly, through Nikon’s Creative Lighting System (CLS), without having to buy any extra tools.

Once your flash is off camera, simply hold it in your left hand, at a 45-degree angle, slightly above shoulder level. The picture below was taken by my dad (I didn’t even notice until he showed me the picture) and it demonstrates what I mean.

Michael Kummer holding an off camera flash

4. Use Walls To Bounce The Flash

External flashes like the SB-700 allow you to change the angle of the flash head. So you can point the flash either straight up and/or at a 45-degree angle. You can also pivot the flash head to the left or right. That allows you to bounce the flash off a wall, which softens and distributes the light since the wall has a larger surface than your flash head. Of course the closer the wall the better it works, so if you’re in a building with a 20ft ceiling, bouncing may not work. Remember that increasing the ISO increases the reach of your flash, so if you think the ceiling is too high but within reasonable reach, try increasing the ISO.

Bouncing flash light
Illustration by Nikon USA

Other options to diffuse or spread light include so-called diffuser domes or a simple sheet of white paper held in front of the flash.

5. Increase The Iso To Extend The Battery Life Of Your Flash

Every time your flash fires, it reduces the battery life, even more so when your flash fires at full power. To decrease the amount of light your flash has to produce you can increase the ISO and let more ambient light onto the camera sensor. But be careful, the higher the ISO the more noise you will have in your photograph. How much noise you’ll see at a given ISO depends on your camera. A D3100, for example, produces more noise than let’s say the new D4. Generally, the larger the camera sensor the better it handles higher ISOs. That makes FX-sensor (D4, D3S…) cameras handle low light situations better than DX-sensor cameras (D3100, D5100, D7000…).

6. Use Ambient Light As Much As You Can

A typical photograph taken with flash at full power has a brightly lit foreground (probably including your subject) and dark background. For the most part, pictures that can be clearly identified as “flash photos” don’t look very good. Instead, they look cold and lack dimension.
To use some of the ambient light, in addition to the flash’s light, you have at least two options:

  • Set your flash to “slow sync” mode. While in Aperture Priority (A) mode your shutter speed changes to 1/60 sec as soon as you switch on (pop up) your flash – no matter how much light is available. That often results in those cold looking pictures I’ve mentioned above. Setting your flash to “slow sync” mode allows your camera to pick a different (i.e. slower) shutter speed, depending on the available ambient light. The result is a photograph with a combination of ambient and flashlight. The downside is that you may get some motion blur if the shutter speed drops too low. So my favorite approach is to…
  • Switch my camera to manual (M) mode, and dial in the aperture I want (for example f/8). Then I take a meter reading and adjust the shutter speed to read 1.5-2 stops underexposed. So without a flash, my picture would be underexposed (dark). But using the flash I add extra light to properly expose the photograph. And because my shutter speed is slower than it should be for a correct (non-flash) exposure I prevent motion blur and instead get a sharp picture.
Flash photo with ambient light

So next time you hear “flash freezes motion” keep in mind, that this is only true if your shutter speed is 1.5-2 stops faster than it should be for a correct (non-flash) exposure.

There is, of course, a lot more to learn about flash photography but as a next step, I’d recommend reading Scott Kelby’s Digital Photography Book Volume 2*. Also, make sure to check out my article about the differences between the RAW and JPEG format.

Leave a Comment