NWA-PCUG Newsletter Article, October 2008
By Bill Funk,
a member of the Arizona Association for Computer Information, inc. (ASCIi)

editor(at)asciigroup.org (click to email author)

I just bought a Digital SLR; with the prices as low as they are, I couldn't resist.

Since I want to take photos of my grandchildren, and the built-in flash isn't as powerful as I need, I bought a new flash. It's the same brand as my camera, and is supposed to be all automatic. But, the photos aren't right.

I thought the better flash would let me take photos inside, and freeze the movement of the grandkids, but the photos are as blurry as with the camera's flash.

What's going on?

You're right, the on-board flashes on most DSLRs aren't very bright. Buying the new flash is the right idea, but it doesn't work the way many people think it does.

You're probably using the camera as a Point & Shoot: setting the camera to make the exposure decisions, and pressing the shutter button. There's nothing wrong with that, but doing things that way won't get your flash to work the way you want it to.

Instead, you should use the Manual mode for exposure (check your camera's manual for how to enter the Manual mode). While you're looking at the manual, check to find the highest shutter speed you can use with the flash, too.

Then, in Manual mode, set the shutter speed at, or maybe slightly below, that speed ( I use 1/125 sec on my camera; it's fast enough to freeze most action), then set the aperture (f/number) for the desired result as far as depth of field is concerned, and set the ISO as desired. Set the flash to auto (check the manual), and fire away. This way, the camera will use the settings you chose, ignoring the amount of light in the scene. The flash will check to see what the camera is set to, and fire itself, checking the results as it fires to give the right amount of light to the scene. Neat, eh?

The way you're doing it will make the flash act as a "fill" flash, meaning the camera's exposure system will use the existing light in the scene to set the exposure, and the flash will intelligently fire to fill in shadows, but not be the major source of light in the scene. This is also the usual way the camera's on-board flash works, even though many cameras will set the shutter speed to take advantage of the flash's extra light to help freeze motion. The problem here, though, is that the on-board flash just isn't bright enough to light up a dark scene (such as a room) very well.

One of the really neat things about digital photography is that, regardless of the actual type of the camera, experimentation is cheap. In this case, once you get the basics of flash use down, you can experiment with different shutter speeds and aperture settings for different results. Also, off-camera flashes like yours will usually let you turn the flash head up and down, and side to side, for bounce flash. With bounce flash, you're bouncing the flash off the ceiling or wall. This tends to spread the light from the flash out to reduce that sharp look that a straight-on flash gives, and it also reduces harsh shadows (as well as changing where the shadows are); more to experiment with!

This brings up another question: if you have an older flash from your film days, can you use it with your new DSLR? The answer is a very firm: maybe. The problem is that most older, film-era flashes have a higher trigger voltage than what DSLRs can tolerate. In other words, using that old flash can cause some expensive damage to your DSLR. There are some devices that can be put between your older flash and your DSLR's flash shoe that will solve the problem. However, a new flash will also work much better with your new DSLR, and do things that old flash can't even dream of doing.

This article has been provided to APCUG by the author solely for publication by APCUG member groups. All other uses require the permission of the author (see e-mail address above).

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