The flash does not remove the ambient lighting per se, that is completely dependent on the shutter speed you’re using. I shoot fully manual so I have control over how much ambient light I want in the photo. With the flash and without the LS, I take the ISO to 400 and bring the shutter speed down to 1/30-1/60 depending on how much ambient light there is and how much people are moving. From there I set the aperture accordingly.

Some caveats about Gary Fong Lightspheres: if you move around a lot, they fall off the flash or get knocked around. When switching from portrait to landscape shots and back again very quickly they often don’t stay put. If you’re switching a lot you’re better off with a diffuser that is attached more securely to the flash or make a DIY solution. The only way your camera’s electronics can read that there’s a diffuser on the flash to compensate for it is a tiny part at the top and side of your flash head. If the LS moves off this part your camera will underexpose the flash if set automatically so it’s very much trial-and-error for manual settings with the LS. As well, the sheer weight of the LS will sometimes move the top of the flash head if you’re at an angle, which can be annoying. I find between the Cloud, Clear, and Amber Dome I use the Clear the most — with or without a dome depends on how low the ceiling is and how much light I want at a lower height.

However, the lighting alternatives such as a softbox or umbrellas triggered by transmitters can be costly and sometimes impossible due to space restrictions or venue restrictions so you have to strike a balance between what you can do, what you can afford to do, and of course what you are willing to do.