Exposure Lights: Photography Tips. Digital Photography Tips: Digital Photography School. Free Adobe Lightroom Tutorials | Layers Magazine. Strobist. Using External Flashes in the Manual (M) Mode. What is the Manual (M) Mode? In the Automatic (A) mode, the sensor of an external flash takes over the control of flash exposure. In the Manual (M) mode, we return to the basics and do everything about flash exposure ourselves. More precisely, we choose an ISO speed and a lens aperture (resp., a flash-subject distance) and calculate the flash-subject distance (resp., lens aperture).
The camera only triggers the flash, and when the flash fires, it always sends out its maximum power and won't cut off early. Therefore, if the aperture is too large or the flash-subject distance is too short, the image is likely to be over-exposed. On the other hand, if the aperture is too small or the flash-subject distance is too large, the image is likely to be under-exposed. What Is the Meaning of the Aperture Used in the Manual (M) Mode?
The manual mode requires two user input: aperture and ISO sensitivity. How to Use the Manual (M) Mode? Examples The following image is Sunpak PZ5000AF's back panel.