I get a few emails every week asking me about strobist stuff. What to buy, what equipment do I use, how to trigger off camera flashes, etc. I can answer those questions. The thing is, I have no idea how I get the light I get sometimes. It’s tricky. You’re dealing with f-stops (aperture), shutter speed, EV values, ambient light, fill light, and plagues sent by God. But the three biggies are aperture, shutter speed, and distance. I’ve only been doing work with flash for a little less than two years, so in my eyes I’m still learning, still making mistakes, but always having fun.
The thing is I usually just wing it with the little bit of knowledge I have. If I want a very shallow depth of field, I set my aperture to 2.8 with my Sigma 24-60 or if I’m using the nifty fifty, I can open all the way up to 1.8. Aperture controls how bright the strobe light will affect your exposure. So with the aperture opened up (the lower the aperture number, the more light enters the lens), the flash doesn’t have to put out as much light. For example, if your aperture is at f/2.8 and your flash power is at 1/4 then that setting will make your exposure a lot brighter than a setting of f/8 and your flash power is at 1/4. Remember, the aperture controls the amount of light coming into the camera. Making sense yet? I usually set the flash at 1/4 as a starting point. I use a Sunpak 383 and a Vivitar 285HV. 1/16 is the lowest power setting on these flashes, although with some other flashes you can drop as low as 1/128.
If I want all of my face to be in focus I can go from anywhere to f/8 to f/16. Of course, using the information from above, you can tell the flash power must increase. And that flash power isn’t just dependent on the aperture, but also whether the light from the flash is being bounced off the ceiling, being used as a bare strobe, being projected through a shoot through umbrella or maybe even being reflected from a silver lined umbrella. Depending on what I’m using, the flash power will need to be at an adequate setting. For example, when I use the shoot through umbrella I’ll set my aperture between f/8-f/10 with the strobe power at 1/4 or 1/2. A shoot through will “eat” up a bit of your light so you’ll need to bump up the flash power or either open up your aperture. Depending on how close the subject is to the umbrella also plays a factor.
And then we have shutter speed. Shutter speed generally controls the ambient light; the light already in the room, or outside, or wherever your location may be. I usually want my flash to be the only light that lights the subject, so I set my shutter speed at 1/250, which is my highest sync speed for my camera. Sync speed is simply the fastest shutter speed you can use with a flash. If it’s set any higher you would see a black line appear in the photo. If you want to know why that happens, look it up on Google. It’s not relevant here. If I wanted the ambient light to come in then the shutter speed would be lowered. The amount of ambient light will greatly affect your shutter speed setting if you’re blending it with light provided by your flash.
Still confused. I know it’s a lot to digest. So here’s a name to remember
Dave’s considered the guru on off camera lighting when it comes to using small flashes. His website, Strobist, is the eminent website to go to to learn about off camera lighting and it’s use. The great thing is, he’s compiled a wealth of information for beginners with his Strobist 101 series. So after you’ve read my post and you’re there in front of the monitor scratching your head, go pay Dave a visit and read the Lighting 101 series. Once you start strobing, you’ll open new doors in your photography.