Manual Versus TTL

TTL flash used with the Nikon SB-5000 Speedlight. Nikon D500, AF-S NIKKOR 14-24mm F2.8G ED. Exposure: 1/1600 sec., ƒ/5.6, ISO 200.

One aspect of photography I really enjoy is watching how technology changes. During my photography career, I’ve seen cameras go from mechanical shutters using ISO 25 slide film in manual mode to mirrorless cameras with articulated LCD screens shooting at ISO 6400 and beyond. Cameras just keep getting better.

Along with camera development has come huge advances in flash technology. Some photographers may still remember calculating strobe exposure using guide numbers and distance scales. In the early ’80s, TTL—or through-the-lens—flash became available and shook up the photography world. Instead of calculating the flash output manually, TTL metering measured the flash output through the camera and stopped the flash burst when the subject was correctly illuminated.

The next benchmark in flash evolution was wireless flash control right at the camera. Using an optical transmitter like the SU-800 with my Nikon flashes, I could wirelessly control and trigger three different groups of flashes in TTL or manual modes. Wireless TTL flash radically changed how I worked during assignments. I could quickly create a striking portrait or illuminate a rock climber on a face.

Wireless flash took another step when radio signals became popular, eliminating the need for line-of-sight between transmitter and flash. Bright midday sun didn’t interfere with the signal, and I could hide flashes behind doors and around corners. Speedlights fired flawlessly using a radio transmitter.

Manual Versus TTL
TTL flash used with the Nikon SB-800 Speedlight. Nikon D2x, AF-S NIKKOR 24-70mm F2.8G ED. Exposure: 1/1600 sec., ƒ/5.6, ISO 100.

Just when I thought flash technology was plateauing, larger strobe flash systems began advancing. Traditionally, AC and battery strobe packs only offered manual flash. But strobe companies began offering TTL flash in monolights and studio systems. These units offered more power, faster recycling and radio triggering. If you were shooting TTL speedlights, moving up to TTL studio flashes was the next step.

But that was the catch. When TTL flash metering was first introduced into studio lights, many photographers balked. Truth be told, I was also on the fence. Why would I ever want to use TTL flash in a studio system? Wasn’t TTL traditionally used by beginners? Did TTL metering really work as advertised?

Manual versus TTL flash—the battle continues today. Most photographers are very passionate about their choice of flash mode and have strong opinions on the subject. But rather than jump right into one camp or the other, let’s look at the pros and cons of manual versus TTL flash and see if using TTL flash in larger studio flash systems makes sense. If you are like me, you might use both manual and TTL flash depending on the situation.

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Manual Flash: Tried And True

Manual Versus TTL
Manual flash using Elinchrom ELB 400 flash. Nikon D810, AF-S NIKKOR 85mm f/1.4G. Exposure: 1/500 sec., ƒ/2, ISO 31.

Manual flash is just that; you set the power output and the flash fires at that level when you hit the shutter. Over and over, the flash fires at exactly the same output. That consistency is the biggest reason many photographers like using manual flash. With manual flash, there is no metering occurring between camera and flash, as there is with TTL.

Manual flash is great for tricky metering situations. Imagine photographing a bride in white one moment, and the next second you are photographing the groom in black. Using TTL metering, your camera system may meter the flash output incorrectly, resulting in under- or over-powered flash shots. Try telling the bride to walk down the aisle again because she looks like a deer in the headlights…not good. Using manual flash eliminates incorrect flash exposures that may occur using TTL metering. Once you determine manual flash exposure, just make sure to keep your flash the same distance from the subject.

I frequently use manual flash with portrait assignments. Since I have plenty of time, I experiment with different flash angles and modifiers while I manually meter the flash output. If I have an assistant, I will have them stand in the same position where my subject will be. Using manual flash, I determine the exact output I need for each light. When my subject shows up, I’m ready to go. Instead of worrying about inconsistent TTL flash output, I can focus on getting a great composition and the right expression from my subject.

But what happens when you are in fast-moving situations and your flash-to-subject distance is changing quickly? Manual metering won’t work if your subject is moving away from you. You might get one good shot, but the rest will be over- or under-exposed as your subject changes positions. Time to explore TTL flash.

Manual Versus TTL
Manual flash using the Elinchrom ELB 1200 flash. Nikon D850, AF-S NIKKOR 14-24mm F2.8G ED. Exposure: 1/200 sec., ƒ/18, ISO 100.

TTL Flash: Fast And Fluid

TTL flash uses all the technology your camera system can muster to determine the correct flash exposure. In an instant, the camera meters the scene for the correct flash output and tells the flash to cease illumination when the subject is properly lit. Speed of adaptability is the biggest reason I like to use TTL flash. I can use TTL flash with fast-moving subjects where I don’t have time to calculate the correct manual flash exposure.

I photograph a lot of adventure sports, which pretty much defines fast-moving, fluid situations. I may try to illuminate a mountain biker as he flies off a jump. Since I can’t walk to where he will be in the air to take a meter reading, I use TTL flash with excellent results. Travel photography is another situation for which TTL is well-suited. If I am photographing farmers in a bustling floating market in Vietnam, my subject-to-flash distance is constantly changing. There is no way I can control my flash distance to the subject, so using TTL flash will give me the best results. Occasionally, TTL flash will calculate the wrong flash output, but not very often. If my exposure is off, I just adjust the TTL flash output using my transmitter.

Which Flash Mode Do I Use?

Manual Versus TTL
Manual flash using Elinchrom ELB 400 flash. Nikon D810, AF-S NIKKOR 70-200mm f/2.8G ED VR II. Exposure: 1/1600 sec., ƒ/4, ISO 31.

I use both TTL and manual flash, but my default flash metering mode is TTL. Why? Because TTL flash generally gets the exposure right.

Here is another way to think about TTL flash. Why eliminate all this advanced TTL metering technology without giving it a chance to work? I use Nikon SB-5000 speedlights, which are expensive flashes loaded with features, including TTL mode. These speedlights work wirelessly via radio control, and paired with a new Nikon camera like the D850, they produce excellent TTL flash results.

But there are times I will switch to manual mode. If I get inconsistent TTL flash exposures, then I go back to manual mode. Or if I know I absolutely must get the shot the first time, and I can control my flash-to-subject distance, then I will use manual flash. On some shoots, I may use both TTL and manual flash. One of my mottos in photography has always been “be flexible.” Situations, subjects and shooting modes may all change during one photo shoot in order to get “the shot.” Don’t put your blinders on and rule out a technique that might take your creative ideas to new levels.

TTL Flash With Strobe Systems

Manual Versus TTL
TTL flash used with the Elinchrom ELB 500 flash pack. 1/1250, F1.4, ISO 100. Nikon D850, AF-S NIKKOR 85mm f/1.4G. Exposure: 1/1250 sec., ƒ/1.4, ISO 100.

Up until just a few years ago, all studio strobe systems used manual flash. Using flash meters, photographers meticulously metered their studio lights and produced beautiful images. Things started to change as photographers began using their camera LCD to meter and set correct exposure for studio lights. The next step was inevitable: TTL studio flash.

Since I always used studio flashes with more controlled scenes, I really didn’t think I would be interested in TTL studio flash. But that all changed when I went to Bhutan a few months ago. I decided to carry the new Elinchrom ELB 500, a small, portable-battery TTL studio system. The ELB 500 puts out 500 watts of power—about the same as eight speedlights—but weighs only around 6 pounds. This studio light was easy to carry and gave me a lot more power to use larger softboxes and overpower the midday sun.

I photographed a variety of people in Bhutan. Sometimes I was able to set up shoots with my lights and subjects fixed in the same position, just like in the studio. But during one shoot, I became a believer in TTL studio flash. We were setting up using one light on a stand and photographing a monk in a small village. Just as we began shooting, the skies broke loose, and it started pouring rain. Rather than put everything away, we started moving positions to get out of the rain. My assistant grabbed the light stand to move it along while I kept shooting. Sometimes my strobe was 3 feet away from my subject, other times it was 6 feet away. But since I was using TTL flash, all the images looked great, and the exposure was perfect. I now use TTL flash all the time with my ELB 500. If the exposure gets tricky, then I switch back to manual mode.

In the end, the best flash mode to use is the one that works the best for you. You might be a diehard manual flash shooter. Or maybe you are TTL flash master. No one will know what flash mode you used, only that you created a beautiful image. In my case, I use both manual and TTL flash. It all depends on the situation.

See more of Tom Bol’s work at tombolphoto.com.

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