The Basics of using a Flash with your Photography (Part 1)

So far all of our discussions have be around using your cameras without any lighting aids... or flash.   Although my personal preference is to use available light, there are benefits to using flash.   One thing I want to point out, this discussion will NOT cover studio strobes.   In the studio, strobes are a fundamental tool with tons of technique and science involved.   What I plan to cover are on-camera flash; the flash built into your camera and hot shoe flash units.   We'll also talk about triggering flashes remotely.

Built-in Flash (pop-up)

Let's start with your built-in flash.   These devices get a bad rap mostly because how they are typically used.   When we buy a nice "fancy" DSLR, it is easy to be intimidated by its power and all its settings.  So the first thing we do is shoot in Auto mode.   This works, and you see the improvements over your previous point-and-shoot camera.   You notice how much more responsive the DSLR is in comparison.  When you press the shutter release, it responds immediately.  The photos seem to have more "pop" and general sharpness seems better.   However, you may also notice that you still get more shots than you expected that are a little too harsh, or you still get that red-eye effect.   You may notice that some of your shots are too dark, despite using the flash.   These are the things I want to talk about as some of the shortcomings of the built-in flash.   That being said, I will also talk about the positive attributes of the built-in flash and how to use it to aid your photography.


External Flash (Hot-shoe)

The next category of flash is an external flash, one that sits in your hot-shoe on your camera.   Typically, they can also be triggered remotely, when not seated in the hot-shoe.   There are a large variety of external flash units.   The variation between them is usually based on their power output, and their ability to pivot and swivel.   This later feature is very important when it comes to bouncing flash off of walls or ceilings, rather than pointing them directly at your subject.  Don't worry, we will discuss bouncing flash a little later.

Since external flash units ride higher than the built-in flash they are less susceptible to causing red-eye.   Don't get me wrong, they can cause red-eye, but that occurs less as the height of the flash increases.

This is the Canon Speedlite 430 EX II.  This is facing straight at the subject.  Notice how high the flash is compared to the lens.  This flash can both pivot (up and down), but also swivel or rotate 180 degrees.

This is the Nikon Speedlight SB-400.  This is closer to entry-level external flashes.  Notice that although higher than a built-in flash, it is closer to the lens than the Canon shown above.  This flash can pivot (up and down) only.  Still very nice to bounce a flash off a ceiling which is often far better than a flash directly pointed at a subject.

Finally, here is the build-in (pop-up) flash on a Canon DSLR.  Since it is on the camera, the flash is close to the lens, which is why they often cause red-eye effects.   Also, notice the size compared to the others.  The output from this flash is less and more pinpoint than the other two.  It is also in a fixed position, whereas both the external flashes have capabilities for moving the direction of the flash.

Now that we understand the different types of flashes available (there are more, but these are very common.)   Let's see how the output varies.

Direct Flash

In this first set of examples, we are going to use direct flash.  This means that the flash output is pointing directly at our subject.   After we cover direct flash and bounce flash, I'll talk about why or when each one comes into play.   If you only have the built-in flash to rely on, you'll want to learn how to use it most effectively.  In the first examples I've taken two extremely basic portrait shots.  Both are with the same camera; both using Auto; one with the built-in flash, and the other with an external flash.   There are some subtle differences between the two shots.

Pop-up flash used

External flash used

As you can see, in these examples the differences are subtle.   The most noticeable is the general light quality.   The external flash produces a more natural skin tone whereas the pop-up flash is a little more harsh.  Due to the positioning of the external flash, the shadow under the model's chin is slightly more pronounced.  Although it's very hard to see here, there is a slight red tint in the model's pupils with the pop-up flash.  It is barely worth correcting in this example.    These two examples are from close up.   The next two examples are from slightly farther away.  They will illustrate some of the challenges of using direct flash, and using Auto with flash for both pop-up and external flash units.

External flash from approx 10'

Pop-up flash from approx 10'

With both of these examples you can see the less than desirable output form direct flash.  Both cause very harsh shadows as seen directly behind the subject.  They also create a strong vignetting effect.

Now I will show a comparison when taking the same shot, but this time I am bouncing the flash off of a wall behind me.

External flash "bounced" of wall

As you can see this is significantly different than what the previous examples.   The harsh shadows are gone.  The color is much more natural and the vignetting is also gone.   This is where external flashes really show their benefit.   

There are absolutely times when direct flash comes into play and must be used.  I'll get into that in the next post, however, the general rule when shooting indoors is that a bounce flash will provide better results than direct flash.