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What’s the Difference Between On and Off-Camera Flash?

04 五月, 2017

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 on and off camera. The entire series, including all videos, articles and lighting diagrams, is available at our website. And feel free to leave a question in the comment section if you have one!

We found a perfect little spot in the Japanese Friendship Gardens in Phoenix, Arizona, to take a portrait of our little ring bearer peeking in on the rings. The bearfoot ring bearer was perfect for this lush setting.

It was a beautiful afternoon and the shade of the gardens was a perfect spot for making images. Behind the subject, I had plenty of direct sunlight dappling through the trees, but the soft, open shade around him made taking a portrait comfortable and uncomplicated.

Our goal with the shot was to compare an on-camera flash to an off-camera flash. In both cases, we used only one light (aside from the sun).

 

 

Our light was the Profoto B2 Off Camera Flash, which is small and light enough to be used both on and off-camera. The battery pack for the light is separated from the head by a cable and the pack can be slung over the photographer’s shoulder for a lightweight and powerful on camera light.

We first measured our ambient light in the shade and in the sunlit trees to determine the very best exposure for the existing light (ISO 200, 1/125 sec @ f3.5). My main concern in the ambient exposure was on the background. If I could keep the trees from blowing out and still get my foreground exposed within the latitude of my camera, I would be happy. The subject would then be filled in by flash.

Swipe the image to see the difference between off-camera (swipe to the right) and on camera (swipe to the left).

(NOT WORKING)

On-Camera Flash

With the ambient exposure set, I turned on my bareheaded B2 and my Air Remote TTL-C in TTL mode. I set the flash exposure compensation on the camera to minus one stop.

When using an on-camera flash, the power of the flash is critical. Adding too much flash, will feel “flashed,” because the natural volume created by the ambient light will be flattened by the strength of the strobe. Anytime I have a flash on my camera, I begin with at least -1 on the flash compensation dial.

In this case -1 stop was perfect. We were able to fill in the shadows and keep the natural volume from the ambient light. Good on-camera flash is all about hiding the fact that you had a flash at all.

With the B2 flash underexposed by one stop, the exposure was perfect and the image looked great. The sun filtered through the trees behind the child and gave the foliage, the grass and the boy a beautiful rim light. The ambient light from the sky above and behind the camera provided the basic volume to his face and the on-camera B2 flash filled in the shadows without giving away the position of the flash.

 

 

 

Off-Camera Flash

The on-camera flash version of the image is a good image, but taking the flash off-camera made all the difference in the world.

We moved the B2 Head to the right of the tree so that its light passed behind the tree and struck the ring bearer’s face from slightly behind, which helped to emphasize the volume in his face, his fingers and legs. No change in the flash power compensation was needed, and there were no addition of any other lights.

The sole act of moving the light 90º off camera augmented the volume in the image to the point that the first shot now seems cheap by comparison. Of course, I was careful to follow the natural direction of the ambient light so that I was not competing with it, but rather, augmenting it.

It is important to note that when we placed the B2 near the tree, the nearly 180º of light spread from the B2 head made the tree light up in a very bad way. So we added a set of OCF Barndoor to block the light from striking the tree.

 

 

 

 

Conclusion

When considering on or off-camera lighting, there are two values to consider: convenience and beauty.

If you are careful, on-camera flash can be beautiful. But with every 10th stop increase in the flash, you steal a little more volume from the shot. It is a very delicate balancing act between filling the offending shadows and removing the beautiful shadows that create volume.

On the other hand, when you take your flash off-camera, adding flash also adds volume, and the act of brightening up the subject is no longer flattening the subject at the same time. The two goals are no longer in competition, but in concert with one another.

 

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