Flash and Ambient Light? Trial and Error?

In continuing flash education:

Is utilizing ambient light and a flash mostly trial and error and/or do you pro-flash guys use a reference card? My gear is 40d, efs 15-85mm lens and a Metz-48 (on camera).

My relevant scenario would be fluid and as follows. Late evening or night (on a deck with ambient lights/water background, etc) and still subjects; such as a dinner party. I want to catch, at least partially, the ambient lights in the background of my subject of course. I am used to daylight fill flash and indoor flash, but night lights and flash is still new for me.

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If I go full auto then I lose the ambient light; however if I go "night portrait" mode it gives me a seemingly slower than desired shutter speed (1/4)? Wouldn't that speed result in more blurred subjects? Remember, this would be more candids and not a staged type shot with perfectly still subjects.

Thus, I have been going at this with a two step approach.
1) CAMERA; I first concentrate on my camera shutter speed, say around 1/30 +- with candids of this sort. This seems fast enough to avoid subject blur yet slow enough to catch ambient lights (at least some).
2) FLASH; My problem has been exactly how to set my flash?
* I've been attemptiong a manual setup but that's seemingly very difficult in fluid situations? Otherwise, do you pros have a general setting for this, say 1/32 or 1/64, with subjects 8-10 ft away?
* My Canon 550ex seemed to underexpose at times in ETTL mode with the camera in creative zones and why I opted to learn manual mode. However, the Metz power can easily be adjusted to compensate even in ETTL mode. Should I go this route instead?


Thanks, Ralph

blurred pictures usually fall below 1/60th, I usually go for manual Mode 90% of the time and the other percent is AV mode at night. BUT if you want to get a good ambient/flash ratio at night time just put your camera on a tripod, that usually solves alot of things at evening photography. Put your flash on a 45 degrees and put some kind of diffuser on it like a stofen or something so soften the blow.

You need the ambient, so:

1. Use wider aperture
2. Higher ISO
3. longer shutter speed

Now aperture will be defined by DOF you looking for. For single person you may get with f1.4 while for groups you may need much smaller aperture.

So use combination of higher ISO and longer ss. If you can't get sharp shots at < 1/100 then don't get below 1/100, bump up ISO. That way (higher ISO) flash also has to work less.

Good starting point is camera in manual mode with flash in eTTL mode. Forget all those creative modes. If your flash under-exposes, use FEC to adjust flash power.

Shoot in M mode and set the aperture, shutter speed, and ISO to properly expose the background.

Your flash (if set to ETTL) should properly expose your subjects. If not, play with FEC until it does.

As already stated, if your shutter speed is too low, the background lights will be too blurry.

Thanks guys. I played around with the flash a little more last night and using it in ETTL with the flash compensation seems the route to go for sure. It's quite an easy flash to set up for that.

Ralph

I tend to set both the camera and flash to manual then use a light-meter to set up my ratio, if I want light bit of fill or if I want to knock down the ambient.

Ralph III wrote in post #12026271
Thanks guys. I played around with the flash a little more last night and using it in ETTL with the flash compensation seems the route to go for sure. It's quite an easy flash to set up for that.

Ralph

Here's another method: Fill light at sunset