fill flash when birding

Ouch! :roll:

Greg Downing wrote:When at a fixed distance from your subject manual flash rocks and is, by far, the most consistent and reliable way to do it. I will never shoot ETTL flash again when shooting birds at a blind etc. I still use the beamer myself and simply account for two extra stops it adds to the range. Since I use manual flash in HSS quite often the beamer is a necessary accessory much of the time. With modern flash units you need not learn guide number calculations etc, but simply use the distance scale on the flash. Subtract two stops (or halve the distance) and you have a nice fill flash effect that is consistent 100% of the time.

Sorry to bring up such an old thread but I'm trying to develop a better understanding of flash technique and this seemed a good place to start.

If you are shooting in Manual Mode and have your flash set to -2 (flash on ETTL) shouldn't the flash output be the same as manually setting it for 1/2 the distance as in the above statement?

The difference is that with ETTL the camera evaluates the scene and works out what "-2" is from there (in much the same way it calculates evaluative exposure for ambient light in any mode but manual).
Someone please correct me if I'm wrong.

rohirrim wrote:

Greg Downing wrote:When at a fixed distance from your subject manual flash rocks and is, by far, the most consistent and reliable way to do it. I will never shoot ETTL flash again when shooting birds at a blind etc. I still use the beamer myself and simply account for two extra stops it adds to the range. Since I use manual flash in HSS quite often the beamer is a necessary accessory much of the time. With modern flash units you need not learn guide number calculations etc, but simply use the distance scale on the flash. Subtract two stops (or halve the distance) and you have a nice fill flash effect that is consistent 100% of the time.

Sorry to bring up such an old thread but I'm trying to develop a better understanding of flash technique and this seemed a good place to start.

If you are shooting in Manual Mode and have your flash set to -2 (flash on ETTL) shouldn't the flash output be the same as manually setting it for 1/2 the distance as in the above statement?

ETTL is basing the exposure on what is reflected back from the subject, and sometimes parts, or even all of, the overall scene, depending on the arrangement of elements in the scene. Since the amount of light reflected back is difficult to predict or determine, as is how the flash will react to it, you results are not consistent.

With manual flash you are simply telling the flash exactly how much power you want and it will consistently deliver it, regardless of subject reflectance.

E/TTL-FLASH works much the same as your in-camera meter, typically, TRYING TO MAKE WHATEVER IS IN THE METER PATTERN A MID-TONE.
Additionally, TTL FLASH exposures will vary with the size of the subject relative to the meter pattern, and the difference between the subject and background tonality.

Manual flash is more akin to using an incident meter or the spot/center-weighted substitute metering method, with exposure based on determining a mid-tone value for a specific quantity of light illuminating the subject. Subjects reflecting values above the mid-tone will appear brighter, those reflecting less than a mid-tone value will appear darker.

Example-

TTL image f/8 at 10 feet of a Bride coming down the isle in a WHITE DRESS... flash underexposes trying to make the dress mid-tone.

TTL image f/8 at 10 feet of Groom coming down the isle in a BLACK TUX... flash overexposes trying to make the tux mid-tone.

Set the flash manually to render an aperture of f/8 at 10 feet and all values at this distance will be rendered accurately. The white dress reflects more light, recording brighter, the tux reflects less light recording darker.

Note-
1) Canon cameras default to Evaluative metering whenever the flash is on, regardless of the meter pattern set.

2) Greatly under used, the Canon FEL button on the Mark II series works as a flash spot meter, rendering whatever is in the spot pattern a mid-tone.

Master flash and a whole new world of opportunity and creativity will be at your finger tips.

Best,

Chas

Chas wrote:E/TTL-FLASH works much the same as your in-camera meter, typically, TRYING TO MAKE WHATEVER IS IN THE METER PATTERN A MID-TONE.

Unfortunately it isn't even that simple, and I know you know all this Chas but I think it is worth elaborating on a bit more.

Since it is EVALUATIVE TTL the meter actually tries to figure out what the tone is and does it's best to make an adjustment to render it properly - not necessarily a middle tone in all cases, even though it does lean toward that direction in most cases (at least it seems), akin to the EVALUATIVE meter which is pretty good at making white white on a sunny day (not a middle tone), but generally screws up (toward middle tone) in many cases.

A true spot meter tries to make everything middle tone, but an EVALUATIVE meter tries to record the tone as it sees it. The problem is that it is pretty blind much of the time.

Bottom line is that learning how to use manual mode and, for that matter, learning the fundamentals of all the methods you are afforded will give you the most control.

Greg, well said ...Eval-as it sees it.

It is the flashes default to Evaluative metering, and subsequent second guessing of the systems built in algorithms that quite often makes determining accurate flash exposure difficult.

When I know ETTL has a tendency for inconsistency, I simply prefer to eliminate the variables... going manual.

TTL camera/flash combos do not use the predetermined ETTL Evaluative algorithms.

Best,

Chas

Thank you all very much for your informative replies. I don't suppose anyone has finished that article/book on all this? I know that I'd be one of the first to buy a copy! Hope I'm not beating a dead horse here but I have a couple other questions.

My understanding is that with E-TTL-II distance is incorporated into the equation. I assume that your above comments apply to E-TTL-II as well, with E-TTL- II doing a little better job?? Does custom function 14-1 help or would using the FEL button be better?

I've used Manual flash and have been happy with the results, but it seems that most of the time I find myself in situations where the distance to my subject is constantly changing, necessitating the need to frequently adjust the flash and often not easy to do when I'm trying to minimize any movement to try and avoid spooking my subject.

Thanks again for all of your information and I'm clearing space on my shelf for that book

Steve,

Book on flash is in the works, along with a bunch of other things.

Regarding Canon CF14

Evaluative... includes as a comp default of - 1.7 EV.
All +/- compensation applied thereafter is in addition to the default.

Average... only the comp that you add/subtract is relevant.

Try shooting a flash image on ETTL and another on Average - 1.7 comp.
Both will appear identical.

Best,

Chas

Bringing up this old thread was quite a shock to me as I didn't pay any attention to the year of the first post. Finding Alex's avatar and comments brought on the tears.