580 ... Evaluative vs Average

[Scott B]

Can someone explain to me in simple layman's terms the difference between setting your flash in Evaluative vs Average?

If I understand it correctly in Evaluative mode the flash (580 on a 20D) is attempting to only illuminate the subject. In Average it's taking the entire scene into consideration. Is that correct?

And if it is correct ... is it better to use fill flash with the 580 set to evaluative?

[sapearl]

Assuming that is correct, I would agree with you.

Let's say you're doing a group shot in the early evening or at night and the people are wearing light colored clothing. For EVALUATIVE the 580 will meter off the facial flesh tones and the clothing, and "attempt" to give you a good fill flash. I say "attempt" becuase normally we have to play around with FEC control to get the type of lighting that WE really want.

If you had it set for AVERAGE, it would meter the dark background and decide "Gee, this place sure is dim.... I better try as hard as I can to illuminate the 50 acres I can see." With that type of output, it will automatically blow out your subjects. The people will be waaaaaaaayy over exposed, and even PS won't be able to put Humpty Dumpty back together again. :o - Stu

.............And if it is correct ... is it better to use fill flash with the 580 set to evaluative?

[TerryM]

And if it is correct ... is it better to use fill flash with the 580 set to evaluative?

you do mean " camera set to evaluative" don't you. I am not aware the 580 can be set. I am new at this and just want to make sure I understand.

[jfrancho]

Check your manual, there are two ETTL metering modes (on the flash), Evaluative and Average. I generally use manual mode (on the flash), so it doesn't matter for me. For the times I use ETTL, I use Evaluative.

[jrsforums]

http://photography-on-the.net/forum/showthread.php?t=46311&highlight=ettlii

[TerryM]

Check your manual, there are two ETTL metering modes (on the flash), Evaluative and Average. I generally use manual mode (on the flash), so it doesn't matter for me. For the times I use ETTL, I use Evaluative.

Help me out here. I have 580 and I cannot find anything in the manual or on the 580 that would suggest it can be set between evaluative and average. Am I blind, or going crazy?

[Curtis N]

It's custom function 14 on the 20D and 30D cameras (and maybe others?). I don't know about the Speedlite.

[TerryM]

Thanks, Curtis. That explaines why I could not find on the 580. I have a rebel and it does not have CF 14, although I just ordered a 5d and it probably will. Thanks.

[jfrancho]

It's custom function 14 on the 20D and 30D cameras (and maybe others?). I don't know about the Speedlite.My bad, 20 demerits for answering at work. I had C.Fn-03 (ETTL/TTL) on the 580 stuck in my head. It is on the camera, as Curtis pointed out. Sorry about that.

[Curtis N]

20 demerits for answering at work.Don't tell my boss, but I downloaded the instruction manuals for my cameras and flash units at work so they're a handy reference.

The strategy works, most of the time. ;) The rest of the time, Leo points out my screw-ups.

[Hermeto]

Thanks, Curtis. That explaines why I could not find on the 580. I have a rebel and it does not have CF 14, although I just ordered a 5d and it probably will. Thanks.

It is C.Fn. 8 on Rebel XT.
E-TTL II
0: Evaluative 1: Average

I don't know about 5D.