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What’s the Difference Between TTL and Manual Mode?

21 九月, 2015

作者: Jared Platt

What’s the Difference? is a series of video lighting tutorials. Each episode responds to a single question. In this episode, Jared Platt compares shooting in TTL and Manual Mode. The entire series, including all videos, articles and lighting diagrams, is available at our website. And feel free to leave a question to Jared in the comment section if you have one!

We were on location to photograph musical recording artist Mindy Gledhill and her tour bus. It was a beautiful sunny day, so the side of the bus was fully lit. This made it perfect to test our Profoto B1 and B2 Off-Camera Flashes in TTL Mode.

TTL is short for through-the-lens flash metering. With either an Air Remote TTL-C or an Air Remote TTL-N mounted on their camera, a photographer can set up her lights, turn them on and fire to get a perfect flash exposure. Then, with the touch of a few buttons, the photographer can adjust the TTL flash compensation right in the camera itself, and when using various groups, can raise and lower power on three separate groups (A, B, C) independently from the camera in TTL and Manual Mode.

The Set Up

Our basic lighting set up consisted of a B2 with an OCF Softbox 2×3′ as a main light, another B2 with a Zoom Reflector as a hair light, and two B1 Off-Camera Flashes to light the shadow side of the tour bus behind Mindy.

Additionally, to ensure that we were in complete control of our subject’s lighting, we used a Collapsible Reflector Gold/White L as a flag to shade her from the sun.

Our main light and hair light were both positioned on the left to mimic the direction of the sunlight. The background lights on the bus were set only with the intention to subtly fill in the shadow on the front of the bus.

 

TTL Mode

Our first exposure with flash was completely TTL with no flash exposure compensation.

We had our lights on three different groups. A: Main light. B: Hair light. C: Background lights on the front of the bus.

Even with the extremely bright glare from the bus trying to fool it, the first TTL exposure was very close to right. The main light was perfect, and the hair light was about 2/3 stops brighter than I would like it. The only group that was off was the background lights on the front of the bus. It was technically correct that the flashes tried to match their exposure to the rest of the bus, but it made the front of the bus too bright to look like a natural shadow.

But overall, the Profoto AirTTL System made a very accurate initial exposure. Now to adjust for our preferences.

 

 

Switching to Manual Mode

The Profoto Air Remote TTL-C allows for full TTL and manual control of flashes on three groups (A, B and C), and manual triggering of flashes on three additional groups (D, E and F). Our lighting setup only used the first three TTL groups.

After our first test shot, we evaluated our image and determined that some manual adjustments needed to be made. So we turned the Air Remote TTL-C from TTL Mode to Manual Mode and began making our adjustments by pressing the power + and – buttons on the remote for the groups.

The hair light group B was 1/3 stop too bright, so we clicked on the power – button three times. (Each click equals 0.1 stop). Our background bus light group C was 2 stops too bright, so we gave the power – button two long clicks. (Each long click equals a full stop).

Once each flash in their respective groups were altered by our command via remote, we began shooting. The results were exactly what we wanted.

 

Conclusion

Using  the B1 and the B2 Off-Camera Flashes in TTL Mode makes the test phase of lighting a shot incredibly efficient. After getting an initial exposure computation through TTL, I quickly change the Air Remote TTL-C over to Manual Mode and make any power adjustments necessary. The lighting solution is then set through the duration of the shoot.

Nowadays I find that I use TTL Mode in some way on almost every photoshoot I do, because the TTL gets me there quicker and let’s me spend my time and focus my attention on the other aspects of the shoot.

 

Watch more video lighting tutorials in this series 

Learn more about the Off-Camera Flash system

Thanks,

Jared Platt

Jared’s website

Jared on Facebook & Twitter

作者: Jared Platt