Flash Photography

It has been said that you are better off spending money on a flash than on another lens. Then of course you have to learn how to use it.

For a long time I hated and avoided flash photography.
I rode a high horse, and would say things like, "real men do available light photography".
Then I came to the realization that "photography is all about light".
Then it hit me: why wait for the light you want, when you can make the light you want!

Getting into the world of flash is like opening Pandoras Box, there is a world of gear and techniques and gizmos that I never would have imagined.
So, .. here we go!

I am shooting with a Canon EOS 20D camera and a Canon 580EX-II speedlight.
Here are my notes on Canon flash gear.
Here are my notes on the Canon 580EX-II in particular.

A great place to get started is The Strobist who seems to have a minimalist flash philosophy. He is into doing a lot with small portable flash gear, and based on his results, I would say he is worth listening to. The other direction is studio gear, massive and powerful flash setups and things I just don't want to get into (seems too much like work).

After just a short bit of reading on the strobist (and other sources, one quickly learns the lesson that you want to get the flash off the camera.
One route is to use pocket wizards (the expensive radio remote control gizmos) and the reasonably priced Vivitar 285 flash units. Another route is to get a Canon 580EX speedlight (like I just did), and the ST-E2 infrared controller (as I did) and have ETTL off camera flash.
Seems like a good way to get started.

The Canon infrared scheme does have its pros and cons. It gives you wireless ETTL, which is perhaps its biggest advantage. It has limited range, and I am told it can be fussy, espcially outside (inside the infrared bounces off of walls and ceilings). Pocket wizards just always work.

The ST-E2 emits a focus assist beam/grid in low light conditions, and I have read of people keeping a unit on their camera just for that benefit, even when they aren't using flash.

The pocket wizards go for $375 per pair, and you may well want 3 of them if you have 2 off-camera flashes. Add some battery packs (like quantum turbos at $500 each) and you can be spending a lot of money in a hurry.

Flash Photography with Canon EOS Cameras

The following link will take you so a superb and extremely detailed discussion of Flash Photography with Canon EOS Cameras written by N.K. Guy. I just discovered that N.K. Guy has a book in the works on this exact topic. It will be interesting to see how the book improves on what is online, and what becomes of the online information when the book comes out. This guide attempts to cover every Canon flash and camera known to man, including ancient film cameras. Because of this thoroughness, it is easy to get lost amidst all the details. Read carefully, be patient, and take your time.

I only really care about using my 580EX-II along with my Canon 20D (well that is not completely true, I do care a little bit about using the on built in flash, but only a little. My Canon 20D is a "Type A" body (type B bodies are really ancient film cameras and such). When he says that the 20D is not compatible with Canon TTL flashes, he is telling the truth. It is compatible with E-TTL (in particular E-TTL-II). Plain old Canon TTL pertains to film cameras and a technology that measured light reflected off the film. Modern E-TTL uses a preflash and measures the preflash using the same electronics that measures the ambient light. (This is the same metering circuit you use every day when you aren't using flash).

One of the most important sections of the guide is the one that explains how a Canon Camera acts in the various modes (P, Av, Tv, M). I don't know how anyone can get along without knowing this, and I don't know of any other place where this is spelled out. Note that in every mode, the camera flash combination are doing ETTL to figure out the flash exposue.

P mode. Here the camera tries to pick a fast shutter speed (something between 1/60 and 1/250 in my case) so I can hand hold the camera. It does one of two things with the aperture, depending on ambient light levels. In bright light (above 10-13 EV) it tries to do fill flash. In low light (below 10-13 EV) it tries to completely light the subject. (full auto mode (the green box) works the same as P mode).
Tv mode. You get to pick a shutter speed (between 1/30 and 1/250 in my case). It picks an aperture to illuminate the background (i.e. always does fill flash).
Av mode. You pick the aperture. The camera picks a shuuter speed, and in low light it may go as low as 30 seconds (not 1/30), so you better use a tripod. It picks an aperture to illuminate the background (i.e. always does fill flash), just like Tv.
M mode. You get to pick the shutter speed AND the aperture. (These determine how you are handling the ambient light). When you push the shutter half way, the LCD display on the flash will tell you the distance covered by the flash! Once again, the flash exposure will be doing fill flash.

Gear

Here are some places selling gear:

Have any comments? Questions? Drop me a line!

Adventures in Computing / tom@mmto.org