Flash vs. Ambient Light Exposure
All right, so let's dive a bit deeper into this flash versus ambient light or constant light exposure. Okay, because something's going to change some things will stay the same now, over here on the constant nor ambient light exposure it's just the traditional exposure triangle. Okay, now constant we define that as a light that's going to stay the same throughout the duration of the shutter speed so your exposure is going to be equal to just whatever that exploded triangle is your shutter speed your aperture and you're so but over here on the flash side well let's assume that this flash we're going to talk about right now is the speed in which this flash fires is actually known as the flash duration and while it's not quite instantaneous going to talk about this in more detail later on so let's assume for right now it's basically instantaneous. Okay, this happens this flash fires and it's one ten thousandth of a second that's how fast it is well, if this is firing at one ten thousandth ...
of a second it doesn't matter what your shutter speed is set too your shutter speed could be on one, two hundred the second it could be one one hundred of a second one fifteen seconds one second thirty seconds long the flash output would still be identical because it fires within one ten thousand of second so while the flash or while the shutter speed is open for one, two hundred second the flash fires and it's that same amount of light regardless of the shutter speed that means that shutter speed does not apply to the flash exposure part of this equation but what stays the same well your aperture and your eyes so they stay the same regardless of whether you're using arcee exposing for constant or ambient light or whether you're exposing for flash for example aperture if I close down my aperture it's gonna cut down the amount of ambient light that's able to come in right it shrinks it down well, it also cuts down the amount of flash that's able to come in just the same as an amulet same thing with eso were digitally manipulating the sensor to make it more sensitive toe light, right? So that sensitivity is gonna have the same effect over ambien or constant light as it would over a stroke so those two things are going to stay the same. But on this side we have flash power, which means that essentially were simply controlling the exposure of the flash by adjusting up and down the actual power the output of the flash it's going to measure we'll talk about the measurement we'll talk about all that stuff more but on this side we have flash power which on lee applies the flash on this side, we have shutter speed, which only applies to constant or ambulance. Those two things in between your return, your s o, is what stayed the same across the board. Now what this whole thing does is it presents some challenges, and also a lot of creative potential for balancing between flash versus ambient light and that's. We're going to get to in the next video.