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-   -   Flash Photography 101, Chapter 3 - A Systematic Approach to Bounced Flash (http://photography-on-the.net/forum/showthread.php?t=177622)

Curtis N 4th of June 2006 (Sun) 23:46

Flash Photography 101, Chapter 3 - A Systematic Approach to Bounced Flash
 
1 Attachment(s)
Before you continue, please read
Chapter 1: Facts that every flash shooter must understand.

Chapter 2: (WHY) SHOULD I GET A FLASH UNIT FOR MY CAMERA?

CHAPTER 3: A SYSTEMATIC APPROACH TO BOUNCED FLASH

While flash photography is complex enough that no single strategy works in every situation, this approach should work well in relatively small rooms with low, white ceilings, such as residential, classroom and office settings.

Why use flash?
Simply put, adding light to indoor settings will allow you to use a faster shutter speed (less motion blur), a smaller aperture (more depth-of-field), and a lower ISO setting (less digital noise) than you could use with ambient light only. The focus-assist light on your flash unit will also help with focusing when needed.

Why bounce the flash?
We are accustomed to overhead lighting, so the shadows produced by light bouncing down from the ceiling will seem more natural looking. When the light from the flash hits the ceiling, it reflects down in all directions, illuminating the entire room. This creates a larger effective light source and produces more even lighting, softer shadows, and brighter backgrounds. When properly used, bounced flash will help to create images that don’t look “flashed” at all. Finally, bouncing will eliminate the redeye problems associated with direct flash.

Color temperature issues
Flash units produce a color temperature that resembles daylight. Incandescent (tungsten) lights have a much lower color temperature, and fluorescent lights have a higher color temperature along with other issues. Since most flash units have enough power to completely illuminate small rooms, my general recommendation is to reduce the amount of ambient light as much as possible by setting the shutter at flash sync speed (1/200 or 1/250 on today’s Canon DSLRs). This will make your flash the only significant light source, eliminating the problems caused by having multiple light sources at varying color temperatures.

Aperture setting
You want an aperture setting that gives you sufficient depth-of-field, but don’t go overboard here. Smaller apertures (higher f/ numbers) will require a higher ISO setting to get sufficient illumination. DOF is a fairly complex concept, but generally speaking for indoor shots of people, f/4 should be enough for a single subject, and f/8 should work for most small groups. These are very general guidelines and the “best” aperture setting depends largely on your artistic goals.

ISO setting
Now that we have the shutter speed and aperture determined, ISO is the last part of the equation to figure out. Since higher ISO settings tend to produce more digital noise, the trick is to set it high enough to get sufficient light without going higher than necessary. This sometimes requires a bit of trial-and-error, but ISO 400 is usually a good starting point.

Test, chimp, and adjust
It’s often difficult to predict what aperture and ISO settings will be required to get proper illumination with bounced flash, so testing is always a good idea. With your camera in “M” mode and set according to the instructions above, and the flash unit in E-TTL mode, take a few shots of someone on the other end of the room. Immediately after each shot, look for the flash exposure confirmation lamp (FCL), near the pilot light on the back of the flash unit (on Sigma units, the “ETTL” indicator on the LCD will blink for 5 seconds). This indicates that the flash had enough power to create what it “thinks” is a correct exposure.

If the FCL doesn’t light, it means it didn’t have enough power for proper exposure with the settings you chose. You need either a wider aperture (lower f/ number) or a higher ISO setting. Adjust accordingly and test again.

If the FCL lights, take a look at your histogram to determine if the shot is properly exposed. If the image is too dark, dial in some +FEC (flash exposure compensation). The need for +FEC is normal with bounced flash and E-TTL flash metering. After adjusting the FEC, test, chimp, and adjust again as needed. More info on how to read a histogram here.

Once you have made these adjustments, you should be ready to make properly exposed images with bounced flash. But remember to check your FCL and histogram often! Many factors, including white clothing, windows, and changing backgrounds can “fool” the flash metering and require adjustments as you go.

Below is my usual configuration for bounced flash. Here are a few other points to remember.

1) Point the flash straight at whatever you want to bounce off. That means straight up for ceiling bounce. Avoid the 45 degree angle technique. This will tend to light only part of your subject directly and create the "hot spot" on the ceiling directly above your subject. Light from directly above is rarely flattering.

2) A 3 x 5 index card attached to your flash head as shown will create catchlights in eyes and provide a bit of direct illumination to fill in shadows.

3) Zooming the flash head to its widest setting will illuminate a larger area of the ceiling (creating a larger effective light source) and throw more light on the card.

4) Ceilings aren't the only surfaces you can bounce off of. A light colored wall beside or behind you can work too!

Next:
Chapter 4 - Guide Numbers and High Speed Sync

mrclark321 4th of June 2006 (Sun) 23:54

Re: Flash Photography 101, Chapter 3 - A Systematic Approach to Bounced Flash
 
Nice work Curtis :)

goatee 5th of June 2006 (Mon) 03:14

Re: Flash Photography 101, Chapter 3 - A Systematic Approach to Bounced Flash
 
Really informative - and much easier to read than the EOS Flash Bible! Looking forward to future installments :).

In2Photos 5th of June 2006 (Mon) 08:49

Re: Flash Photography 101, Chapter 3 - A Systematic Approach to Bounced Flash
 
Thanks Curtis. I just picked up a 430EX and need all the help I can get. I printed Chapter 1 and will print this and put it into a little binder with other useful info. I bought the 430 used and it came with a Sto-Fen Omnibounce. What are your opinions of this diffuser or any diffuser for that matter?

Curtis N 5th of June 2006 (Mon) 09:20

Re: Flash Photography 101, Chapter 3 - A Systematic Approach to Bounced Flash
 
Quote:

Originally Posted by In2Photos
I bought the 430 used and it came with a Sto-Fen Omnibounce. What are your opinions of this diffuser or any diffuser for that matter?

They all have their place, and some are more versatile than others. I don't have a Sto-fen because I think there are other ways to get results just as good (like the 3 x 5 card pictured). I have seen some outstanding shots taken with the Sto-fen, when used correctly. Like anything else, it takes some practice and experimentation to learn how to get the best results.

Spiral Photo 5th of June 2006 (Mon) 09:24

Re: Flash Photography 101, Chapter 3 - A Systematic Approach to Bounced Flash
 
Awesome. Some good info in this thread.

Also, don't forget that along with bouncing off the ceiling, depending on what you're shooting you can also bounce off the walls, the floor, your shirt, a friend's shirt, a reflector (of course, and if what you're shooting makes it feasible), your hand....and in fact, I was considering purchasing a set of different-colored cotton gloves just for bouncing the flash to produce different colors, like using gels. :) I have noticed, however, that using red creates some unpleasant results. Red just seems too easy to overexpose.

nation 5th of June 2006 (Mon) 11:39

Re: Flash Photography 101, Chapter 3 - A Systematic Approach to Bounced Flash
 
Thanks for another great tutorial Curtis.

euro 5th of June 2006 (Mon) 14:06

Re: Flash Photography 101, Chapter 3 - A Systematic Approach to Bounced Flash
 
One thing that always confused me is that how boucing works with P, Av or Tv mode. When used ceiling to bounce, I always need to go to M mode. Because too many variations, such as the height of the ceiling, the color of the ceiling, the point angle of the flash etc, will affect the final output, I have never had good luck with P, Av or Tv when I point the flash to the ceiling. In the other words, TTL doesn't really help in case of using bouncing. It makes sense to me because the flash only measures how much additional light is needed through lens before it really get fired. If flash is pointing to somewhere else, it cannot make a correct judgement. But I still feel that the flash can do better job other than always requiring me to make test shots. Did I miss anything?

Curtis N 5th of June 2006 (Mon) 14:21

Re: Flash Photography 101, Chapter 3 - A Systematic Approach to Bounced Flash
 
Euro,
A couple things to keep in mind:
1)Av, Tv and P modes are designed to meter for ambient light. If you don't want ambient light to contribute significantly to your image, there's no point to using those modes. That's why I recommend "M" mode for indoor flash.
2)E-TTL is just as useful for bouncing as with direct flash, if not more so. No matter where the flash head is pointed (or what diffuser you may attach), it measures the light from the preflash coming through the lens and adjusts the output accordingly.
3)I recommend test shots, only to ensure that you have enough flash power, given your aperture and ISO settings and the conditions (height of ceiling, size of room, etc.). E-TTL still does the metering.

Your post seems to indicate a bit of confusion because you start by discussing Av, Tv and P, then you talk about "TTL". Ambient light metering and flash metering are completely separate. Did you read Chaper 1?

euro 8th of June 2006 (Thu) 00:39

Re: Flash Photography 101, Chapter 3 - A Systematic Approach to Bounced Flash
 
Curtis,

Thanks for your reply.

Quote:

Originally Posted by Curtis N
No matter where the flash head is pointed (or what diffuser you may attach), it measures the light from the preflash coming through the lens and adjusts the output accordingly.

I think this is what makes me confused. When you are saying preflash, do you mean the flash will flash when I push the shutter half way down? If it is, it makes sense to me. Is the preflash the one fire through a red plastic on the flash?

I am using digital rebel + sigma EF500 DG ST.

Thanks,
Euro

encor 8th of June 2006 (Thu) 01:39

Re: Flash Photography 101, Chapter 3 - A Systematic Approach to Bounced Flash
 
First, I'd like to say hello to all of you as this is my first post to the forum.

Quote:

Originally Posted by Curtis N
1)Av, Tv and P modes are designed to meter for ambient light.

Hmmm, correct me if I'm wrong, but doesn't the P mode always meter for flash? AFAIK while set to the P mode the camera consideres the flash to be the main source of lighting and cares only a little for the ambient light - I guess it sets the shutter to the value of no less then 1/60 and if that means the background will be dark then so be it. The only way one can expose for the ambient light while using the flash is to switch FROM the P to any other mode.
At least that's what I always knew about the Canon flash system: "Never use the P mode when using a flash":)
Actually I always work in the M mode when shooting indoors and the Tv mode when shooting outdoors.
Regards

Titus213 8th of June 2006 (Thu) 13:27

Re: Flash Photography 101, Chapter 3 - A Systematic Approach to Bounced Flash
 
Euro - I believe the red light you see is the focus assist light on the external flash. The preflash is fired just before the full exposure, it is white, and is generally about 1/32 power. It's the same flash you would get if you pushed the FEL button (*) assuming you are not using CFn04-1.

Sorry - if you are using a 300D you have no CFn04 so the * is FEL.

RoxxyG 9th of June 2006 (Fri) 06:38

Re: Flash Photography 101, Chapter 3 - A Systematic Approach to Bounced Flash
 
Thank you very much for this information.. easy to read, and easy to understand. Much appreciated. I have recently started using M mode for all my indoor flash work and have noticed a huge improvement, using these tips and techniques.

:-)

RedWingNut 9th of June 2006 (Fri) 16:05

Re: Flash Photography 101, Chapter 3 - A Systematic Approach to Bounced Flash
 
Thanks for the good info. Could be most useful sometime in the future for many.

IamRoger 13th of June 2006 (Tue) 23:01

Re: Flash Photography 101, Chapter 3 - A Systematic Approach to Bounced Flash
 
One technique for none moving objects or staged photos with bounce flashing is to hit the exposure lock on the area that you want properly exposed. It sends a preflash to check properly exposed area. Then shoot the photo. This works great when "p" mode, but the downfall is it sets f stop for you so based on ISO and limits creativity...


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