Flash 101: On-Camera Flash

Written by:

Lisa’s note: Things have been a bit busy at the Jeff and Lisa household lately, which explains the lack of posting. Things should be back to normal soon though. To the new subscribers, hi! Welcome to Beyond Megapixels. Feel free to browse through the popular posts, and the rest of the archives. With that out of the way, enjoy Jeff’s article on the basics of flash photography.

There are two ways for you to use your flash: on-camera and off-camera. There are pros and cons for both and we’ll tackle the biggest ones here to get you started on flash photography. Before I forget, when you go through other websites you might wonder why they use the word strobes rather than flash. It’s the same thing so don’t get confused.


In Part 1, we will be discussing On-Camera flash. When on-camera flash is mentioned, the first thing that comes to most people’s minds is the tiny flash unit found in point-and-shoot cameras and entry-level DSLRs. What we’re referring to in this article are external flash units mounted on a camera’s hot-shoe.


1. No red-eye. Since external flash units are about a half a foot away from your lens, the chances of red-eye happening are slim to none.

2. Portability and mobility. No don’t need to bring anything but your camera and flash unit. You also don’t need to move around to adjust the settings on your flash since it’s right there. You have flash capability in a moment’s notice.

3. Bounce your flash. Most external flash heads allow you to swivel it from left to right and up and down. This gives you the ability to bounce your flash to make the light hitting your subject softer and more flattering. Take note that if the surface of wall or ceiling you are bouncing from is not white then the light hitting your subject will have some tinge of the surface color

CC Photo by Okko Pyykko

4. ETTL metering. Electronic-Through-The-Lens or ETTL refers to how your camera meters a scene. It basically measures the light as it goes through your lens. Dedicated hot shoe flash units can make use of ETTL metering when it calculates how much flash is needed to properly expose your subject. This feature saves you a lot of time if you’re just starting out in flash photography since you don’t need to fiddle with the intensity of your flash.

5. Fill-flash mode. Fill-flash refers to the flash just giving off enough light to make sure there are no harsh shadows on your subjects. What happens is that your camera measures the ambient light and properly exposes for this while telling the flash to expose for the subject. Some manufacturers require you to activate fill-flash mode either in your camera or on the flash unit while some like Nikon and Canon automatically defaults to fill-flash when there’s enough light in the background.

6. Focus assist. Built in flash helps in auto-focusing (AF) by throwing off small bursts of light when ambient light is low to help the camera focus. This is really annoying and in my opinion could induce epilepsy. External flash units assist in auto-focusing by throwing off red light which is very faint and non-obtrusive. Below is a photo of the focus assist lamp on the Canon 430EX II.


1. Full-frontal light. The reason why on-camera flash photography looks so unnatural is that the light source is noticeably coming from the camera. This is not how we regularly see our surroundings unless you walk around with a flashlight attached to a helmet on your head. This problem is being slowly addressed by manufacturers by making complex algorithms to balance flash and ambient light. You can also try swiveling the flash head as mentioned above but that only works when you’re near something to bounce the light on which isn’t always the case.

CC Photo by trentroche

2. Shadows on the wall. As a rule of thumb, you should avoid using flash when the subject is near a wall since you will mostly likely end up with the subject’s shadow on it.

CC Photo by Beige Alert

3. Flash fall off. Flash fall off refers the situations wherein the subject was properly exposed by the flash but the background is completely dark. This is due to the simple fact that you cannot light the entire background with your flash unit.

CC Photo by Dawn Ashley

The most important thing to know when purchasing an external flash unit is that you need to make sure to buy one that works with your camera. A lot of bad things can happen if you place an incompatible unit on your camera’s hot shoe. If you’re lucky then the only thing that could happen is that the flash will not fire but there have been incidents where either the flash or camera short-circuited. In our opinion, it’s better to buy one that’s the same brand as your camera.

Ready to take your flash photography to the next level? Proceed to Part 2 of Flash 101: Off-Camera Flash.

Related Reading:
How To Get Soft Diffused Light From Your Flash

Previous Post:

Comments are closed.