As mentioned in an earlier post, the Godox system now allows radio remote TTL flash at up to 100m from the camera when used on most camera systems, including Micro Four Thirds at last!
The Godox AD600B is a Bowens S mount studio flash with attached 500 shot lithium ion battery and ability to use a remote head also with Bowens S mount lighting accessories.
This makes it a great option for location shooting, but how well will its recycle time keep up with the Olympus OM-D E-M1 Mark II rapid fire burst modes of 10fps and 15fps mechanical shutter (NB. unfortunately you can’t use the flash in electronic shutter mode rapid burst modes as sync speed is far too slow).
The short answer is extremely well IF you drop the flash output level to around 1/16th or 1/32nd of full output.
When testing I have taken the flash out of TTL mode and used Manual mode so I can see exactly what outputs will keep up.
Let’s first look at 10fps (the usual LOW burst setting on the camera):
At 1/16th output or less there were ZERO dropped frames where flash did not fire.
At higher outputs up to 1/4, there were sequences of mainly 2 (and sometimes 1, 3 or 4) consecutive frames where the flash did not fire:
At 1/16th + 0.3EV, you get 29 frames then drops 2, then 11 frames then drops 1, etc.
At 1/16th + 0.7EV, you get 14 frames then drops 2, then 5 frames then drops 2, then 6 frames then drops 2, etc.
At 1/8th output, you get 9 frames then drops 2, then 4 frames then drops 2, then 3 frames then drops 2, then 4 frames then drops 2, etc.
At 1/4 output, you get 3 frames then drops 2, then 2 frames then drops 4, then 2 frames then drops 3, then 2 frames then drops 3, etc.
At 1/2 output, you get 2 frames before dropping frames
At full output you get 1 frame before dropping frames as it does a full recycle.
Now let’s first look at 15fps (the usual HIGH burst setting on the camera):
At 1/64th +0.7EV output or less there were ZERO dropped frames where flash did not fire.
At higher outputs up to 1/8th output, there were sequences of mainly 5-6 consecutive frames where the flash did not fire:
At 1/32nd output , you get 26 frames then drops 5, then 10 frames then drops 5, etc.
At 1/16th output , you get 10-11 frames then drops 6, then 5 frames then drops 6, etc.
At 1/8th output, you get 5 frames then drops 6
At 1/4 output, you get 3 frames then drops frames
At 1/2 output, you get 2 frames before dropping frames
At full output you get 1 frame before dropping frames as it does a full recycle.
Summary:
If you don’t want any dropped frames for the 1st 25 frames, use 1/16th+0.3EV output or less at 10fps, or 1/32nd output or less at 15fps.
In reality most of use just need the first 9-10 frames or so, and if this is the case then 1/16th at 15fps is fine, as is 1/8th output at 10fps.
The flash sync on the Olympus OM-D E-M1 Mark II in TTL mode or manual mode with this outfit is 1/250th sec (it can be pushed a little faster if you use PC sync only connection to the trigger and only use manual mode).
The kit will allow HSS / Super FP mode but this does drop the flash output and significantly affect the recycle times when using TTL FP mode as well as increase the risk of over-temperature protection system kicking in (at 50 full output flashes or 100 1/8th output flashes, or 150 16th output flashes) which forces the unit to recycle at 10 secs instead of a full recycle of 2.5 secs, and you should then cease firing for 10 minutes.
At 1/16th output, the t0.1 flash duration is 1/3448th sec which should be plenty short to stop most action such as a ballet dancer in a studio and at a GN of around 16m at ISO 100, you are still getting a reasonable output, so that when used at ISO 200 which is the base ISO of the Olympus cameras, you need to use f/11 with the flash at around 2m away from subject with just the standard Bowen’s 7″ reflector head in place – enough output to get it back a bit further.
Bouncing off an umbrella or shooting through a double diffused softbox at 1/16th output will give you exposures around ISO 200, f/2.8 at a flash to subject distance of around 3m, but at f/2.8, ISO 200 and 1/250th sec, you do then run into potential issues with a bright outdoor ambient lighting – in this case, use the bright outdoor ambience to backlight your subject.
At 1/32nd output, the t0.1 flash duration is 1/4651th sec which again should be plenty short to stop most action.
Of course, you could go down to 1/128th output on the remote which gives a t0.1 flash duration of only 1/8130th sec, and although the AD-600B itself allows you to manually dial in a 1/256th output setting which gives a t0.1 duration of 1/10,000th sec, this is not currently possible to use with the Godox XT1-O transmitter which will set it back to 1/128th output as lowest output.
If you need more power output at 1/16th output, buy two AD600B units and a 1200Ws bulb and the 1200Ws remote head connected to your two AD600B units.
