I wouldn't have thought that a non-reflex camera would find its way into my kit. I did, and do, carry a Nikon P7700 as an emergency "shoot flash in bright sunlight" camera, but its tiny sensor made for some rather noisy images, and a lack of sharpness that I could feel more than I could see. True, a pixel is a pixel, but compact cameras with small sensors just don't produce the kind of images I've come to expect.
Flash! The one thing that drew me to the X100s was its leaf shutter, with its inherent ability to synchronize speedlights up to a top speed of 1/4000 of a second. This presumes that your chosen exposure time (shutter speed) is longer than the duration of the flash at the appropriate power output. This makes my X100s a potential go-to camera for those situations where flash may be needed to enhance a photo when the primary lighting is provided by direct sunlight, a notoriously powerful light source. David Hobby has a very detailed explanation of t.5 and t.1 times if you want a more detailed explanation. However, a clever photographer can do a systematic trial-and-error method to determine the optimal shutter speed/flash output settings when using manual settings, which is what these times are all about. Here's how:
- Find an indoor location where the ambient light is enough to allow for proper auto-focusing, but not so strong as to influence the exposure of your sample images.
- Be sure your camera and flash are OFF.
- Mount your camera on a tripod (optional).
- Attach your flash to your camera.
- Turn your camera an flash ON.
- Set you flash/speedlight to 1/2 power output.
- Set your shutter speed to 1/125 of a second to start, and make an exposure. Examine the playback image. If you can display a histogram, so much the better.
- If the image is too bright, stop down your lens or decrease the ISO setting until you get a centered histogram. If it is too dark, set the lens to a larger aperture, or increase the ISO setting. When your aperture/ISO combination yield an centered histogram, continue to the next step.
- Set your shutter speed to 1/160 of a second (or the next shorter exposure increment) and make an exposure.
- Compare the two images. If the histogram is displayed, you will (hopefully) see no difference in their horizontal alignment. This tells you that both shutter settings can take full advantage of the flash's 1/2 power output. Without the histogram, you can get a rough idea by just comparing the images.
- Continue to decrease the exposure time until the histogram shifts noticeably to the left. This indicates that some of the light from the flash is being "clipped" from the tail end of the discharge curve. When you see this, you know that you've had exceeded the minimum shutter speed for your flash when set to 1/2 power.
To be continued...