Does Lumiquest Screw Up the Meter Reading?

[Mum2J&M]

I used to own a Lumiquest pocket bouncer when I had my 35mm slr. I didn't realize they still even made such a thing. But I see they now have some large softbox-ish style bouncers? Anyway, I was wondering if these gizmos mess with the camera/flash metering systems. Just seems like a sort of obstruction the meter just wouldn't understand. I was curious because I'd consider buying one again mostly for fill use, kind of like the gold color option. Anyone have any experience with them? I always felt like such a dweeb carrying that thing around. :rolleyes:

[PacAce]

If you are talking about ETTL, the answer is no. Flash metering in ETTL mode is done by firing a preflash and then metering the light that is reflected off the subject and into the camera through the lens. You can have all the "obstructions" between the flash and the subject and it won't make a difference as long as the light put out by the flash through those "obstructions" is strong enough to properly illuminate the subject. Of course, if the subject is beyond the maximum range of the flash with the modifier attached, the subject will come out underexposed.

You'll usually lose on average from 1.5 to 2 stops with any type of modifier attached to the flash. Sometimes more.

[Curtis N]

Most modifiers spread out the light and bounce some of it off the ceiling (sometimes that's the whole idea). Indoors, this bounced light will usually light up your background more than direct flash. This is usually seen as an a good thing.

But this brighter background affects the E-TTL flash metering, so typically you'll need a bit more +FEC when you use such attachments.

And as Leo mentioned the efficiency of your flash is greatly reduced with such modifiers, so you'll probably need to increase your ISO to get the power you need.

[Mum2J&M]

Interesting. Thanks, guys, for the words of wisdom.