Phaim (fāme) — Larry Becker’s Blog

Some Off-Camera Flash Basics

—Plus One Killer Resource

Posted on 07 May 2010

I don’t always have the time to answer NAPP members or blog readers in great detail, but recently a question came to me as the result of one of my posts here about flash and I took the opportunity to answer my reader at length. Since there’s a lot of good information in my reply, plus a link to an awesome, free source for learning about flash, I thought I’d share it here today.

Some time ago I wrote about my SB600 and some attachments to make them into a slave flash. I never really explained why someone might want to do that and I also realized that, while my Nikon D200 and many mid-level to high end Nikons can “command” off camera strobes via Nikon’s Creative Lighting System (CLS), there are some great cameras (my friend has a Nikon D40x) which don’t have remote flash/commander capabilities built in. If your camera has a flash Commander Mode, you could use that to trigger your SB600 (or SB800 or SB900). Also, my reason for adding optical flash capability to my three SB600s is because I’m buying a new studio strobe and I want my speedlights to be slaves to it. That way I only have to trigger my single studio strobe with the camera, and that strobe will trigger all my optical slaves. Sure, I could use a radio trigger (mentioned below) but my solution is more budget-friendly.

Since this reader didn’t have a camera with Commander Mode or other external flashes, her options and needs weren’t quite like mine. She could use her SB600 on camera easily, bouncing it off ceilings or walls for better flash coverage & softer light, but moving it off camera gets a bit more tricky, because you have to come up with a way for the camera to trigger the flash at just the right instant. She bought the two small adapters for her SB600 that: A) add a sync port to the flash foot, and; B) the optical trigger that can plug into that new adapter. So here’s my detailed reply regarding her options for off camera flash… (I hope it helps some more folks too):

I have a couple things for you. First, I’ll answer your question here to the best of my ability, then I’ll give you a great resource for lots of small flash info in plain English.

Let’s forget the external SB600 for a minute… Your camera’s pop-up flash is designed to work in 2 different ways, TTL and manual. TTL stands for “Through The Lens” and it’s pretty much automatic and has metering capability. What happens in TTL mode is, when you press the shutter release the flash blinks twice very quickly. The first blink is so the camera can take a meter reading of the light and make adjustments internally, and then the second flash, almost instantly after the first, is the one your camera uses to capture the image. If you pay close attention to your pop-up flash when you take a picture, you’ll usually see it “flicker.” That’s the double-flashing, metering, adjusting, and actual image capture and it happens FAST! In TTL mode your camera’s menus allow you to adjust flash compensation to slightly override the camera’s decisions about the flash. In other words, the TTL might think your picture needs a particular amount of light, but you think the final exposure looks too bright. In that case you would decrease the TTL flash exposure compensation. If the image looks too dark, you can increase the flash compensation.

Now let’s add the SB600 into the mix. If you mount the SB600 in your camera’s hotshoe (you must clip the pop-up flash closed first) your camera in TTL mode can do the same stuff it did with the pop-up flash, but now you have much more power and versatility than a simple pop-up because the flash is bigger, stronger, and can be pointed at walls or ceiling or wherever you want. It can bounce off various surfaces you choose to improve the image capture.

Off camera options
Off camera lighting allows you to be much more creative in where you place your lights and how you make a scene look. Moving the SB600 off camera can be done 4 ways, but TTL (your camera’s automatic light metering and adjustments) can no longer be used in most cases.

1) You can buy a radio transmitter for your camera and a receiver for your SB600. This will only fire the flash and TTL won’t work so all your exposure adjustments must be done manually by you. This is the most expensive option but allows you the most versatility because you can put the flash almost anywhere within 300 feet and you don’t need line-of-sight between your camera and the SB600. 2 popular brands of radio transmitters are Pocket Wizards and SkyPorts. For the minimum of 2 units you would need, you would have to spend $220 or more.

2) I don’t think the D40x has a PC sync port so you’d need to buy a hotshoe-to-PC adapter plus a long PC cable and then you could hook a PC cable between your camera and your SB600 with the hotshoe adapter you bought from FlashZebra (leaving the optical slave thing out for now). This would probably cost you $30-$50 more at this point and you would be restricted by the length and inconvenience of the PC cable.

3) You can go the optical route you’ve already started. First you need to set your camera’s pop-up flash to Manual mode. I would also recommend turning it down to the lowest possible setting in your camera’s menus. In Manual flash mode there will NOT be a pre-flash for metering purposes. Just the single blink at exposure time. When set at its lowest setting, your camera’s pop-up flash will have a minimum contribution to the lighting in the picture, but it’s plenty bright to trigger any off-camera optical slave. Now, if your SB600 has the hotshoe adapter and the optical slave plugged into that, and if the optical slave piece can “see” the flash from your on-camera pop-up, THAT will trigger the SB600 at the right time. With this setup you’ll need to manually increase or decrease your SB600’s power, or change your camera’s settings, or both, to get the exposure you want. Bright sunshine in outdoor situations and other flash photographers in the vicinity are the two things that can typically interfere with optical slaves.

4) You could buy a Nikon SU800 InfraRed commander for around $250. This looks like an SB600 but has a red plastic IR transmitter instead of a flash bulb. An SU800 is essentially a commander for any SB600, SB800 or SB900 and it can control up to three groups with several flashes per group. This would allow you to remotely increase and decrease your SB600’s power and even use the TTL mode. The down-side is that it uses InfraRed light to trigger the SB600 (or SB800 or SB900) and therefore requires line-of-sight between the SU800 and the speedlight in question. Also, since it’s using InfraRed light instead of a visible flash to trigger, there’s no chance of some extra light from you pop-up flash unintentionally adding to (contaminating) the light in your image.

So… I think that’s the long answer to your question. Another GREAT source of information for beginners to flash and off-camera flash is a blog called Strobist. He has a collection of great tutorial blog posts to walk beginners through Lighting 101. I have a link to that page here. And on that page, be sure to watch the 7 minute embedded video because it’s a great place to start. Then read the various articles from the Lighting 101 collection as you become interested in the various topics. Eventually you’ll grow as a strobe shooter and you’ll become more interested in the day-to-day posts. But for now, do what you can to tackle the brief video and the Lighting 101 series.

http://strobist.blogspot.com/2006/03/lighting-101.html

Of course there are parallels with other flashes and camera manufacturers, but the point is to learn the various options for triggering a flash (or more than one) in as many ways as possible so that you can maximize your ability to control the light.