Old Post - Question - Regarding Flash and Exposure Comp.

[michael_wilson9]

I just purchased a new 580 EX II for my 40D.

I was reading through some old posts and came across this one.

I was hoping that you might be able to clear things up for me.

Where I am confused is the Ambient Exposure settings.

My questions are below the actual post.

 

 

 

Here is the post.

 

 

Nadine Ohara - SF Bay Area/CA , Jul 26, 2005; 07:43 p.m.

 

C Jo--the background going darker when I use a fair amount of fill flash is with both film and digital, although because

digital is so immediate, I confess I tend to use ETTL and adjust it (or the camera settings) on the fly, using manual

flash only when I find I can't control it otherwise. With film, I overexpose the background 1/2 stop to kind of

compensate for this effect. With my 20D and 580EX, I either use manual mode with flash in ETTL evaluative, using a

handheld incident meter or sometimes I use aperture priority. Like you, I "place" the highlights where I want and

proceed from there. Outdoors, when I want fill flash, I use the flash in evaluative flash metering mode, usually taking it

down in relation to the ambient exposure, although it is supposedly doing that to some degree already (the

mysterious Canon flash). Inside, when the flash is the main source of light, I use averaging flash metering mode.

 

I have found the lazy way of using the 20D, though, and that is using aperture priority and ETTL evaluative. I mostly

use minus ambient exposure compensation in AV mode, though, as I've found that no minus ambient exposure

compensation gives you overexposed shots with any scene except for completely even shade. This method is the

lazy way of placing the highlights. I will routinely dial in between -1 and -2 ambient exposure compensation and leave

the flash in "homebase", which, for me is +2/3. For instance, given a scene where you have a backlit, sunlit subject,

I will go -2 ambient exposure compensation and leave the flash at +2/3 evaluative (because it is already doing auto fill

flash reduction). This combo gives me a very balanced exposure with detail in the highlights (not blown) and subjects

well filled in. If the scene is less contrasty, I'll go -1 on the ambient. Lazy, but very fast, as you just evaluate the

scene, dial in the comp, and shoot, and most of the time, the exposure is great. This works as well with light

backgrounds and darker foregrounds. For completely even shade, no ambient comp and -2 on the flash.

 

Ben--not be negative, but I am thinking the Lightsphere won't help with the blown whites problem, and, to comment

on your other thread, I think in the forward position, it will affect your auto thyristor flash sensor. It might even affect it

in the upright position, since there is nothing to block the light coming downward out of the unit.

 

 

 

 

Would she be referring to the exposure compensation on the camera when you say Ambient Exposure

Compensation?

 

When she talks about leaving the Flash in +2/3 are you talking about increasing the power in ETTL mode and leaving

it at evaluative?

 

I usually shoot in AV/TV or M - mostly AV mode.

 

What metering is suggested on the camera itself? Would evaluative in the camera be the best with Flash mounted.

 

Thanks in advance,

Mike