Sometimes natural light is the best light, especially when it comes through a window or better yet, a window with some scrim over it. However, I like to flash the crap out of everything I shoot.
I never used to like using flash, when I was first starting photography I hated flash, partly because I didn't have a flash, but also because I didn't know how to use it, so I learned to shoot without it, using the available light, finding where the light was and moving my subjects into the light. Come Tafe and university, I still hated flash, refused to use it, I found that it got in the way of my shooting style and had to force myself to use it more and more. It wasn't until third year when I finally realised there was a reason for using a flash (obviously) and I made myself use it more and more.
Since working as a full time photographer I hardly never use flash on an assignment. The reason I use flash is because it is the easiest and best way IMO to isolate your subjects from the background. I've always loved lifestyle/editorial styled photographs and knowing how to use your flashes is the best way to do that - i've found.
There are often times when I walk onto a site and just stand there looking at the light. The old "put the hand in front of the camera and check the light" trick is used 99% of the time when walking into a room or out in the open. Often i'm looking at the quality of light, sunny, overcast, the direction it's coming from and how the shadows are falling from the light - if any.
Sometimes I come across a scene that I want to use and am too stubborn to change it even though the light isn't right. There are many times when I want to put my subject in a certain spot but the light isn't right, casting too many shadows, throwing too much light onto my subject - or not enough, that's when throwing in a bit of flash helps - a lot.
As you can see, I like using flash. I try to make it look as natural as possible, although you can tell there's flash in there I try not to make it look overdone.
So why do we go with natural light sometimes? Good question, I don't even know myself, but I normally go with natural light if i want a certain 'look'. The word 'look' is a pretty broad term, especially as a photographer but for me I will use natural light if the light is right. It doesn't really explain much, but just like when I shoot a frame and I know it's a good shot, there's something inside that lets you know "yep, that's the shot". Sometimes the natural light compliments the subject matter and I will often opt to use that instead of flash. The shot below, I didn't feel the need to have to isolate my swimmer from the crowd or from the beautiful mountains behind him, he is part of the image, a part of the story. The light hit the mountains perfectly and the sun was creating a beautiful rim light on the subjects.
Sometimes the natural light is SO good you have no option but to shoot it. The shot below in the steelworks was a natural light shooters dream. There was a BIG open doorway on left and a HUGE skylight 20m above the subject which lit up the whole area. The steelworks was under maintenance, so all the doors were open, normally it's dark and gloomy in there, however on this day everything was open resulting in a beautifully lit photo. The skylight above is what makes the photo, the light lit up enough of the steelworks to add some location and context to the shot. The beauty of soft light (like below) is that it almost creates no shadows, the light fades off gradually without the harshness which you normally see in broad harsh daylight.
Sometimes I mix flash with natural light. The below shot could've been replicated with flashes, but in this instance the natural light was perfect. I had my subject sit in her sitting area where the light streamed in perfectly lighting her up adequately. As my foreground subject who is a cleaner, was in deep shadow because I was exposing for the daylight outside, I added a little bit of fill flash to light up the inside of the house and her to create a more natural looking scene.
Like my point earlier, sometimes natural light is just too good to say no.
Relying purely on natural can be challenging sometimes as you need to make sure you're not putting your subjects face in complete shadow. Using natural light slows me down, it makes me wait for the decisive moment when the light falls perfectly on the subject, it's very much a waiting game, but when it works, it works very well indeed.
So what's my conclusion? I really don't have one, there is no right or wrong answer. Light is light, use what works best in your vision, use what works best to best tell your story.
Until next time..