P#42: Flight Crew on Deck: The Power of Exposure

Exposing the Flash

David Tejada: The next one was done for a healthcare client of mine up in Nebraska. I was asked to do a photograph of the helicopter service that they have. I brought the pilot out. We're inside the hanger there. (click the image for a larger version)

In this particular photograph, I used high speed sync. What that is for your listeners, there is an ideal sync speed for flash photography and in most cases, it's around 1/250th of a second. What that simply means is that in our DSLR cameras and in film cameras, we have two shutters.

It's a curtain that actually travels from the bottom of the sensor to the top of the sensor. At 1/250th of a second, the first curtain has opened all the way up to the top of the sensor and it is just before the bottom curtain follows behind it and closes. At 1/250th of a second, your sync speed, your sensor is completely wide open. When a flash goes off, you can illuminate the scene.

This particular photograph was taken using a specialized sync speed of 1/8000th of a second. We call this high speed sync. At 1/8000th of a second, the two curtains that are traveling across your sensor is a very, very narrow slit. If the strobe just went off once, just one big blast of light, you would have a very well exposed thin slit going across horizontally in the picture.

What high speed sync allows you to do is as that small slit, that curtain is rising at 1/8000th of a second, your strobe is pulsating the entire time so that every section of that split opening as it travels up from the bottom of the photograph to the very top, the strobe is going the entire time.

I have actually taken this picture at 1/8000th of a second at nearly wide open which gave me a shallow depth of field. It's a very, very wonderful asset to have in some of these modern DSLR cameras.

Audri Lanford: That makes a lot of sense, yes.

David Tejada: Did I confuse anybody with that?

Audri Lanford: I don't think so. I think you explained it very clearly, actually.

David Tejada: Good, good. Normal flash, if you do anything faster than your sync speed, you will have a dark section in your photograph with only a well exposed area and that is the exposed area with flash, when you're using flash.

In Conclusion:

The power of modern DSLR cameras lies in their versatility. In this flight crew shot, that versatility is what really sets the photo apart.