The Aperture in Flash Photography (shown in a Live Shoot)

This is the 3rd and last episode of this series where I explain you the role of each Exposure Triangle factor in Flash Photography when ambient light is not lighting the subject. Here we are looking at the Aperture. If you have not seen the previous episodes i invite you to do so:

• The Shutter in Flash Photography (shown in a Live Shoot)
• The ISO in Flash Photography (shown in a Live Shoot)    

Below is a photograph taken with the Canon 5D III: Flash 1/2 power, ISO 400, Shutter Speed: 1/200, Aperture 6.3:

You can see we have Megan (the model) correctly exposed and the rest of the scene is dark as the nothing from the ambient light was recorded.

If we now open up the Aperture to F4 without changing anything else, you can see that while Megan is now over-exposed:

Subsequently, when reducing the Aperture down to F11 without changing anything else, we can see that Megan is now underexposed:

Conclusion

I hope that with these few examples you now understand the power of the Aperture in Flash Photography: It manages how much of the flash output is being recorded by the camera. Of course, it is worth adding that the primary effect of the Aperture as seen in the early episode on the basics of Photography: Creative Aperture – Depth of Field remains in Flash Photography (ambient light exposure, and Depth of Field). So before dealing up or down the Aperture value, one should really consider how much of Depth of Field is required in a given shot.

What’s the difference between using ISO and Aperture in Flash Photography?

Well, the difference lays with their very own basic characteristics. We know the ISO affects the exposure but at the cost of image quality. The Aperture affects the exposure as well, but the only side effect will be the Depth Of Field (if we put aside any lens quality consideration). In studio photography, the DOF is not as important so if one wanted to change the flash exposure without changing its value (i.e. the flash is at full power already or at its lowest and with the lowest ISO) then changing the Aperture value would affect the flash exposure. Remember we are in the context where the flash is the only light source. If you enjoyed this article, please share it with your friends using the Facebook, Pinterest, Google+ and Twitter buttons.