I am setting the custom functions on my 1DS III. It asks if I want average or evaluative when using flash. I am going to be doing some inside event shots this week and will be using a 580 EX II. I will probably use the white card and shoot the flash up to soften the light. which metering mode would you use?

Also, does anyone EVER just shoot the flash directly at a group of 3 to 4 people and get good results. If so, I would sure like to know how.

thanks,

Brad

If you have a neutral-colored ceiling, you should always bounce, but shooting straight up may not be the best bounce area to use. In addition you may want to check out the information at strobist.com on gelling the flash to match the ambient light temperature. I would use evaluative. I shoot the flash directly at a group of people only as a last resort, and even then I'd try to soften it, including by using high ISOs, and as slow a shutter speed and wide an aperture as possible whilst still getting the shot.

Maybe something like an ultrabounce might help. You point the flash head up, but the light is bounced and diffused from a 45deg sheet, so you get good flash power and much softer shadows.

The pop-up white card is to create a catchlight when bouncing off the ceiling, not a bounce card. Bounce can produce diffuse lighting if shooting distance and ceiling height is ideal, but when flash comes down off the ceiling at too steep an angle the result is dark shaded eye sockets.

All things considered a camera - flip flash bracket which keeps the flash head about 12" above the lens in both landscape and portrait mode is the best approach. Raising the flash hided the head shadow and puts the one from the nose beneath it or behind it where it isn't noticed. See: http://super.nova.org/DPR/Design/ for a explanation of the cause and effect of modification and how the various modifiers work. See http://super.nova.org/DPR/DIY01/ for a easy to make reflection-diffuser which eliminates the variable of ceiling bounce.

Indoors with flash you will want to shoot in M at ISO 200 - 800, depending on how close you are and how much noise you find acceptable. Set shutter speed that you can hand-hold and decrease duration as needed up to the x-sync limit of your camera if you want the background darker. f/5.6 is a good starting baseline for aperture - the adjust as needed.

With camera in M foreground flash exposure is controlled in ETTL mode entirely with FEC. Evaluative compares all the zones, finds lightest and darkest and tries not to blow the lightest ones. Keep your main subject closest to the camera when composing the shot so the metering is not fooled. Set the playback so the overexposure warning can be monitored.

Do some testing around your house before the event to practice. Get a small white towel as target. When you can expose and make it look normal, white with texture, the exposure is optimal. Try evaluate and average, see which works best for you. Raise FEC until white textured highlights such as white shirts just barely start to black out, then back it down 1/3 stop (1-click) and exposure should be optimal. Monitor and adjust on the fly as you shoot because each scene will be interpreted slightly different.

See: http://super.nova.org/DPR/Canon/TTL/ and http://super.nova.org/DPR/Canon/MultiCanon/ for more info on Canon using flash.

I don't want to appear stupid but when you talk about FEC are you talking about the adjustment on the flash or a camera adjustment?

stklaw wrote:
I don't want to appear stupid but when you talk about FEC are you talking about the adjustment on the flash or a camera adjustment?

FEC = flash exposure compensation.

You can set it on body or flash, but flash settings override camera settings.

Where do you set it on the body? 1DS III?

stklaw wrote:
Where do you set it on the body? 1DS III?

I don't have the 1Ds III, but all Canon bodies have a little button with a lightning bolt and a +/- symbol on it. On my 1D II it's on the left hand side in that cluster of 3 buttons on the shoulder

I see that. It moves the Exposure Compensation + or -. Is that any different than when you push the shutter down half way and adjust the Exposure compensation or the same thing?

Thank you for all your info.

Brad

Exposure compensation (EC) affects the ambient exposure when the camera is in P, Av, Tv or the other modes. Exactly what EC does varies with mode, but on a Canon, which doesn't have auto ISO it will affect shutter speed (in Av) or aperture (in Tv) or both (in P and other modes).

EC adjustments also may affect the flash exposure in Tv mode because EC in Tv changes the aperture of the camera, which in turn will require more or less flash power to produce the same foreground exposure with the flash. However unless you are using the flash in M mode you will not likely notice this because in ETTL the pre-flash metering will automatically compensate for changing apertures by changing flash duration. Tv mode is a poor choice when shooting flash for that reason.

When shooting flash indoors M mode for the camera mode will produce the most predictable and consistent results. In M mode, EC is not active but the meter still is. As you adjust aperture and shutter manually the line on the -2 ..... 0...... +2 scale will move. When the line is centered in M mode the camera meter is telling you that combination is what is guesses will produce a correct exposure - about what you would get if using Av and centering the needle with EC =0

What is a bit confusing is that Flash Exposure Compensation or FEC uses the exact same -2 ..... 0...... +2 scale to display the setting. When you press the FEC button the display changes from showing the state of the ambient light exposure to showing the flash compensation setting.

Indoors in a dark room with the camera in M at say 1/125th and f/5.6 the needle on the -2 ..... 0...... +2 scale (before the FEC button is pressed) will be typically pegged at -2 simply indicating the shutter / aperture / ISO combo will result in under exposure if no flash is used. Slowing it shutter, widening the aperture or raising the ISO speed will eventually cause the needle to move to the right. As the needle moves to the right the background gets lighter in the photo. When the needle is centered the background should be correctly exposed - more or less.

When you press the button the -2 ..... 0...... +2 scale changes to display Flash Compensation. If the foreground is too dark, dialing in + FEC makes the flash duration twice as long resulting in a 1- f/stop increase in exposure. If the highlights are blacking out in the info playback mode indicating overexposure a minus FEC adjustment will reduce the flash duration and the exposure. Take a shot, evaluate, adjust as necessary.

There is also an FEC adjustment on the flash itself controlled with the round dial (on a 580ex). It has a -3 / +3 stop range. If FEC is entered on the flash it overrides the camera setting.

Caveat: If you set +2 FEC using the camera, decide it is not enough and then dial +3 FEC on the flash, when you change the FEC on the flash back to 0 the setting will revert back to the +2 still dialed in via the camera. To avoid confusion I always make it a habit to set the camera FEC back to 0 (centered) before using flash FEC.

Also, FEC only works when the flash in not already working at close to its max. capacity. For example if you are shooting far away or bouncing off the ceiling and the flash is firing at 100% of its max power at FEC = 0, dialing in FEC = 1 will not correct underexposure because there is simply no more power reserve left. So it is necessary to have situational awareness of what the maximum range of the flash is. That is simple to find out. Just flip the flash into M mode at 1/1 (full power) and take a shot. If it is underexpose it indicates the effective range of the flash has been exceeded for the selected ISO and aperture.

Edited by cgardner on Mar 31, 2008 at 10:10 PM GMT (Reason: Clarification of Tv mode)

stklaw wrote: It asks if I want average or evaluative when using flash.

Evaluative flash exposure mode is a "smart" mode that attempts to determine what your subject is, then expose that subject at midtone. As a general rule, it will take the brightest returns from the preflash as being your subject. That means that usually the closest object is considered to be your subject, although a white object a little farther away than a dark subject might be picked.

Evaluative generally works pretty well as long as you understand its limitations. Shooting past, over, or through something will tend to cause problems. If you shoot a subject through a doorway, the flash will expose for the doorway. If you shoot a subject down a hall, the flash will expose for the near parts of the hallway. And so on.

Evaluative flash exposure has special processing to try to ignore point reflections from an unbounced flash when trying to determine what the subject is. This didn't work very well in previous incarnations, but Canon claims that big advances were made in this processing starting with the 1DmkIII. If you bounce your flash, this isn't an issue anyway.

Because evaluative flash exposure takes the brightest return as being your subject, and exposes that at midtone, almost the entire histogram will be left of center. Some people freak out about that, but if you think about it it's perfectly reasonable.

In contrast, the average flash exposure mode is a "dumb" mode that simply blasts out enough light to bring the entire scene up to midtone. If the background is far away or non-existent (a subject standing outside in the open), the flash may need to nuke the subject until it glows in the dark in order to get the desired average results. This is how older flash exposure systems—thyristor autoflash, for example—work and many people have come to think of this as "correct" flash exposure. Those people tend to think that evaluative flash exposure is "too dark" because the subjects aren't blown out and glowing.

Edited to add: The histogram from the average flash exposure mode looks more "normal", too, although for the typical case where the subject is closer to the flash than anything else is, the subject is way up on the right side of the histogram. Still, many people value a balanced histogram over a properly exposed subject.

For fill flash, evaluative flash metering is (IMO) the clear method of choice. Also note that in daylight conditions, evaluative flash metering will automatically reduce the flash to prevent overexposure from the combined effects of ambient and flash, while average flash metering will not… with average flash metering you must adjust FEC yourself.

A final note: with Flash Exposure Lock the flash metering mode is overridden to Spot (if available on the particular camera model) or Partial. The subject is presumed to be at the center of the scene when the FEL button is pressed, and that subject is exposed at midtone. When using fill flash in daylight conditions, it is up to the photographer to adjust FEC to prevent overexposure when using FEL.

Edited by Doug Pardee on Mar 31, 2008 at 01:10 PM GMT (Reason: Added comment on histogram in average mode)

Where do you set it on the body? 1DS III?

Brad, with the greatest of respect here - Have you read the manual ? I'd expect you to know where the camera control buttons are way before asking what you asked. We're talking about a $ 5 or 6K camera here ?(maybe I've had a bad day I dunno....)

Reggie, please excuse my laziness. I read the manual cover to cover whenever I bought the camera. However, as you can see I did not retain very much.

On the other hand, this thread talking a lot about Flash Exposure Compensation.

Brad

Camera manuals provide information on what controls a camera has, but most don't provide much in the way of practical advice how to most effectively use them. The price of the camera doesn't affect that very much. The manual for a $300 P&S will assume that the user will be using it in auto mode most of the time. The manual for a $3,000 DSLR will assume the user has or will acquire the knowledge of how best to use the creative control features elsewhere. It creates a niche market for people to write tutorials explaining which buttons to press when

stklaw wrote:
Reggie, please excuse my laziness. I read the manual cover to cover whenever I bought the camera. However, as you can see I did not retain very much.

On the other hand, this thread talking a lot about Flash Exposure Compensation.

Brad

Brad, so you mean you still don't know what is FEC and whereabout is the FEC button? Look from the top, left of your 1Ds3, it has the Flash sign with + & -. depress that button and use your big wheel to move left or right = -/+

I hope get it right for you.

Got it, thanks.

Doug Pardee wrote:
stklaw wrote: It asks if I want average or evaluative when using flash.

A final note: with Flash Exposure Lock the flash metering mode is overridden to Spot (if available on the particular camera model) or Partial. The subject is presumed to be at the center of the scene when the FEL button is pressed, and that subject is exposed at midtone. When using fill flash in daylight conditions, it is up to the photographer to adjust FEC to prevent overexposure when using FEL.
quote]

When you press the FEL button (on my cameras, the * button) you want to center your subject in the frame and then re-compose. Is that correct? Also, does FEL cancel itself after one shot?
Thanks,
Tell huh.... why is my type the same color as the quoted text?