FJ Strobes with High-Speed Continuous ShootingUpdated a month ago
Overview
Mechanical shutter Frame rates as fast as 10fps to 20fps (camera dependent) can be supported if the power level on the FJ strobe is level 4 (1/32 Power) or below. Based on the strobe’s distance from the subject or the Ws (Watt second) rating, you may need to raise your camera ISO and/or open/widen your aperture (f-stop setting) to accommodate the lower power levels required to maintain the fast frame rates.
It’s important to understand how power levels, recycle times and Camera settings work together to provide consistent proper exposures when using flash with high frame capture rates.
How fast is too fast?
Westcott FJ gear provides industry-leading recycle times to allow you to record images at the fastest rates available when using flash. Still, you need to practice caution when choosing settings to avoid a conflict between your frame capture rate and the recycle times of the strobes.
Not considering the recycle time at a given power level can cause underexposed images as the strobe may be unable to recycle at the rate of capture. A strobe requiring a second to fully recycle, cannot provide full power at frame rates of 10 per second.
Reducing the manual output level of the FJ strobe will decrease the amount of time required to recycle the unit for the next exposure. At full power, FJ strobes recycle within a second or two (model dependent).
Use of TTL and High Speed continuous capture.
As stated above, maintaining a power-level of 4 or less will provide recycling times at, or near the maximum mechanical shutter drive speeds (approximately 20fps).
When using TTL (through-the-lens) metering to set your flash output level, working with a low ISO or narrow apertures (larger F number) may require the strobe to automatically produce a higher output than the level 4 (1/32) power levels required to maintain the fastest frame rates.
As with manual strobe power settings, choosing a higher ISO or wider aperture may be necessary to provide the fastest recycle rates. Typically, you will want to set your camera’s TTL flash exposure menu to First shot metering or the rate of capture may be slower than you expect.
Tips to Maintain Quick Recycling
- Moving the light closer to the subject will allow you to reduce the output of the strobe while maintaining your exposure. Halving the distance of the light to subject will give you four times the amount of light on your subject. This will allow you to reduce the output by 2 levels. Power 7.0 (¼ power) at 8 feet = power 5.0 (1/16 power) at 4 feet.
- Each doubling of the ISO will allow you to reduce the output level by a factor of 1 stop (½ the amount). Power 7.0 at 200 ISO = Power 6.0 at 400 ISO = power 5.0 at 800 ISO
- Moving to a wider aperture will allow you to reduce the power output by a factor of 1 for each stop of adjustment. Power 7.0 at f5.6 = power 6.0 at f4.0
- Each time you set the manual power lower or cause the strobe to fire at one level less in TTL, you reduce the recycle time by at least 1/3.
- Set your in-camera TTL metering to first shot