Today’s blog is going to be more for the mere photographic minded (and I hope the rest of you will forgive me for that). I don’t usually write about technique, because there is plenty of information about how to handle a camera out there – and I am more interested in the creative process of photography anyway. But this time I will make an exception, simply because the technique I am about to describe may boost creativity as well.
This post is going to be about how to make a shoe mounted flash not only work, but give an interesting and quite different look to your pictures. Flash pictures you may ask? That is always gonna be harsh contrast, lousy quality and no control on your part… But really, no! Before the digital era I used to be sharp and very good at using flash. I had to. Back then I was shooting slides, and to get the best quality I would usually use a slow film at 100 iso or even Kodachrome 64. When light went low, you had to be able to either use a flash or set up a whole shebang of lighting equipment. I got good with the handheld flash. At some point I almost as a rule used the flash – day or night. It became part of my signature. But when the digital era took over, suddenly I didn’t need the flash any more, I could just ramp up the iso-setting of the camera, and I was able to shoot in any lighting condition. How cool was that! I packed down the flash, and never look back again. Until recently that is. Not long ago I finally dug into my camera bag again, and found the old flash (and found out that I actually had to buy a new one, too), because it’s not bad at all, but really just another creative device in my toolbox – when I need that special look.
The main factor for success with the shoe mounted flash (or even better if you hold it in your hand with an extension cord) is to mix available light and light from the flash. And the trick to gain control of this mix is to think about the process as taking two pictures on the same frame – even though it happens at the same time – in one exposure. First you take a picture with the available light and then you take the same picture with the flash (or the other way around, if you like to think about it that way, because it really doesn’t matter, it’s only a mental exercise; as I said it happens simultaneous – at least for the argument here). And what happens when you add two pictures on top of each other? The two light sources will add up and make the final picture lighter – too light. Which means you will have to make each captured picture darker, so the total adds up to a correct exposure. Thus you will have to underexpose them.
Let’s see how that works in real life. And I will start with explaining two useful set-ups using manual exposure control. That will make it easier to understand the process, even if you are never going to shoot manually. Let’s say you are shooting indoor. You want to take advantage of the special look you can get from mixing equally available light and light from the flash. To get a correct added exposure you set the camera so that it underexposes the subject lit by available light with 1 exposure value (either stop down the aperture one step or cut the exposure time in half). And you set the flash 1 exposure value down, too. Where the flash hit the subject the total of the two underexposed pictures (which albeit is but one frame) will give you a correct exposure, while where only available light is picked up, the subject – usually the background – will be underexposed and that is fine. It doesn’t sound too difficult does it? Try it out!
Here is the other set-up I mentioned I would explain: It’s midday sunshine. The shadows under the nose and in the eye sockets of the person you want to photograph are black. Not to mention if the person wears a hat. Time to mount the flash again. But this time you will only underexpose the flash. You set it to minus 2 exposure values. The exposure for the available light is as if no flash was added. That’s it; you are good to go with a so-called fill-in flash. Two exposure values down on the flash doesn’t sound like a lot, but it actually brings the light from the flash so much down, that it will only affect the shadows. That’s why you with this set-up don’t need to underexpose the available light. Here is the beauty: You can mix any ration of available light and flash as long as the sum of the two exposure values you step down are -2. In the first step-up the available light was -1 and the flash -1. Hence the sum is -2. In the second setup the available light was 0 and the flash -2. Again the sum is -2. So if you want to give a little more flash than the equal set-up in the beginning, you could for instance go for -½ EV for the flash and -1½ EV for the the available light. The sum is still -2. It works!
I’ll stop now, and get back to the automatic approach next time. I have already written too way too much, despite the fact that in my previous post I complain about myself too often writing too long texts. So thank you for staying to the end.