Flash 101

bbaker35 · Dec 1, 2005

Let me start by saying that I am such a newbie here, but learning alot and enjoying it too. I picked up a 350D a couple months ago and have taken quite a few shots. I have the kit lens which sucks and also the low end Canon 75-300 f4-5.6 (which I have been very dissapointed with.) I am getting the 50mm 1.8, but am also thinking about getting a flash too. I have asked for the Canon 420X Speedlight...

The only problem is..When I get it I won't have any idea how to use it, what it can do or when to use it.

Is there anyone familiar with Flashes (i'm sure there is) That can give me some flash 101? Any help would be greatly appreciated! Thanks!

B

jstuedle · Dec 1, 2005

A flash when used properly can be a great benefit to your craft. Learn how to use the flash out doors in daylight as fill. Dial the output down about 1/2 stop to fill in the deep shadows without over powering the subject. Another thing I do is attach the flash to the camera using a remote cable and hold the flash out about 2 or 3 feet from the lens. Use a diffuser on the flash to reduce it's harshness. I shoot Nikon, so I can't help with specifics, but your new flash should come with a decent manual. Read up and practice, a lot! And enjoy your craft, play with it until you know your camera, flash, and lens as if they were the preverbal back of your hand. It won't take as long as you think.

Rob · Dec 1, 2005

RTFM :mrgreen:

Seriously though, it should be pretty straight forward as it matches the camera and should be a clever enough combo to do the job well.

As for when to use flash... use flash when there isn't enough ambient light to capture your subject. Typically any shots of people indoors are good flash candidates. The other big use I can think of off the top of my head is to increase the lighting on the subject to darken the background and minimise it's impact on the shot.

Now get out to the pub and take lots of pictures of people in front of windows!!

Big Mike · Dec 1, 2005

Read this http://photonotes.org/articles/eos-flash/ it's been called the Canon EOS Flash Bible

You probably won't understand it all...I sure don't. But there is a lot of good info in there. Read it again at a later time, when you have a basic idea of how the flash works.

bbaker35 · Dec 1, 2005

This is also probably an easy question, but what's ambient light? I've read about it, but have seen no definitions...

jstuedle · Dec 1, 2005

but what's ambient light?

Existing light, available light, any light you have to work with before supplementing with your artificial lighting.

bbaker35 · Dec 1, 2005

Oh geez..
that was an easy one.. lol

Thanks JST..

jstuedle · Dec 1, 2005

It had to be for me to be able to answer it.

bbaker35 · Dec 1, 2005

Now I have another question..This one might be a little bit more complicated, but I don't know.

I have been going to the canon photo workshop website and looking at their tutorials. There are obviously ways to control the brightness (if that's even a word.lol) of the background and the subject seperately. They use an example of a girl in front of a lake at sunset. In some pics they change some setting to make the background look like day sunset or night. then in others the background stays the same, but the girls looks like she has less flash a little more flash, and then a whole lot of flash. It says you can do this in manual modes like Av Tv or P. I don't currently have any flash except the one that's built in. So my questions are...

How do I control the background light?
How do I control the amount of light on the subject?

Anyone?? Thanks...

B

Big Mike · Dec 1, 2005

You're asking the right questions...so I think you are on the right track.

Exposure is controlled by the aperture (hole in the lens) and the shutter speed (the length of time the shutter is open). That is the basics...learn how those two things work and correspond to each other.

Now with flash photography, the flash goes off very fast...much shorter time than the shutter is open. With modern equipment, the camera/flash measures the reflected light and quenches the flash when enough light has come back to the camera. So for your subject (girl by lake for example)...the flash illuminates the subject very quickly...and the shutter speed does not matter. Only the aperture and the flash output will determine the exposure of the subject.

Now, the flash will obviously not light up the whole world...so the only light that the background (lake & sunset) will show is the light that is already there....ambient light. Now because we are using the aperture to control how much exposure the subject is getting...we can use the shutter speed to determine how much exposure the background gets from ambient light. A longer shutter speed will give more exposure to the things lit with ambient light (like the background).

So to get the shot of the girl with a dark background...a fast shutter speed.

To get the lake & sun set in the shot as well...slow down the shutter enough to expose them with ambient light.

Did that make any sense?

bbaker35 · Dec 2, 2005

Wow..Actually it does make sense, and quite a bit at that. I figured that the external flash had nothing to do with the way the background appeared. So then the only thing the flash would be used for in this situation would be to make the girl's appearance brighter or darker??

bbaker35 · Dec 2, 2005

Ok..thanks for the help everyone..Now my next question on the subject. I also ordered a flash diffuser (funny that someone would order something and not even know what it's for) ...What is a flash diffuser for exactly? Is it hard to use? How do you decide when to use it?

Sorry for the basicallity of the question, but I'm so new at this.

Unimaxium · Dec 3, 2005

A light diffuser slips over the end of the flash to diffuse the light coming out of it. So instead of the light beaming directly out of the flash and reflecting off of the subject, it is scattered first, causing the lighting result to be softer than without a diffuser. This is supposed make shadows less harsh and more pleasing.

Keep asking questions... you seem to be learning well!

Big Mike · Dec 3, 2005

A diffuser can make the light softer...but it also blocks/absorbs a bunch of light...which make the rating of the flash lower (less powerful at a distance)...and it will also use up the batteries faster.

Not to say they are no good...just that it's not something to use all the time. I think bouncing the flash off of a wall or ceiling is a better way to get soft light from the flash.