When I bought the Fuji X100 as a walkabout camera I found an unexpected bonus, the Fuji has a leaf shutter in the lens not a focal plane shutter in the camera body. This rare and is great news and here is why.
Stick with me for the next bit….
In simple terms the focal plane shutter in most cameras allows light onto the imaging sensor through a gap that travels across the sensor. The size of the gap varies depending on shutter speed from tiny (4000th of a second).
At slow shutter speeds the gap is fully open across the sensor which means that the very short duration of light supplied by a flash unit illuminates the whole sensor.
But for short fast shutter speeds the the traveling shutter gap is narrow meaning that it exposes the sensor a bit at a time as it passes across the sensor so the flash will only illuminate the part of the sensor which is uncovered by the gap. In practice this means using shutters speed of 1/250th of a second or slower, limiting exposure choices.
Focal plane shutter
Examples of flash using the focal plane shutter in a Fuji XT1 at different shutter speeds. Note the shutter travels vertically.
The focal plane shutter is fully open during the exposure and the flash lights the whole scene 180th of a second (Fuji XT1).
The focal plane shutter is only partially open during the exposure and the flash lights only part of the scene 200th of a second (Fuji XT1).
The focal plane shutter is mostly closed during the exposure and the flash lights parts of the scene 300th of a second (Fuji XT1).
The leaf shutter in the lens opens from the center outwards this means light is falling on the sensor throughout the exposure and the flashgun can fire at anytime during this period . This is incredibly useful as fast shutter speeds can be used. In practice I use this to make different exposures for the subject( that the flash is lighting) and the rest of the scene which is lit only by the ambient light.
In the photographs below I have used a very fast shutter speed to underexpose the background making it appear darker that the subject. Using the fast shutter speed also allowed me to open up the lens aperture to make the background out of focus.
The flash has exposed Katy and the chair that she made using hand tools only, making her stand out from the background but still showing the environment that she works in.
Camera: FinePix X100, lens: fixed 23mm (35mm equiv) exposure: 1/4000 sec; f/2.8; ISO 200
Had I used the 250th of a second which is a usual synch speed on cameras, I could not have used the f/2.8 to soften the background.
This test shot was made with one Canon speedlite and a reflective umbrella, a soft box on the speedlite would have allowed more control and I could have made the concrete floor darker. Because the flash was off camera it needed triggering and in this instance I used a cable from the cameras hotshoe to the flash. I have a wireless trigger but it’s limitations would not allow the fast shutter speed.
The same technique was used for Nic and Katy and their award winning hand made chair