speedlight 430ex III rt

TonyUSA · Oct 20, 2017

When using with TTL. The guy on the youtube said we should leave High speed sync on at all time as HSS will kick in when it need it. Is this true? I though to turn on HSS only when I need to use HSS.

Thank you,

Tomasko · Oct 20, 2017

Which guy? Also what was his reasoning behind the advice?

Overread · Oct 20, 2017

HSS allows the flash to sync at shutter speeds faster than the sync speed of the camera (typically at or slower than 1/200 or 1/250). It does this by firing a pulse of light instead of a single shot of light; the series of pulses requires the flash to fire at a lower power per pulse so the overall effect of the flash is far less than normal.

HSS is ideal for fill flash where the light is lifting shadows, but not contributing the main exposure of the shot in a strong manner (unless, of course, you have a lot of flash units). It also becomes rather tricky for action because any fast motion is going to show blur as it catches the haze in the series of flash shots instead of a single action stopping pulse of light.

In theory if you are controlling the shutter speed directly (shutter priority - manual mode) you could remain in HSS as it is only needed at shutter speeds faster than the cameras sync speed. If, however, you're letting the camera control the shutter speed it might well go slower than idea, since the camera meters without the flash (TTL and auto metering tend to work best for the flash as a fill flash light source).

It strikes me that, without the context of the video, the person in the video likely only uses flash for fill lighting or they are directly controlling the shutter speed for their shoots.

TonyUSA · Oct 20, 2017

Tomasko said:
Which guy? Also what was his reasoning behind the advice?

at around 7:27.

TonyUSA · Oct 20, 2017

Overread,

I understand what is HSS but my concern is that do I have to leave HSS on at all time on the flash even if I am not using HSS. I normally only turn on HSS when I need it. Thank you for nice explanation on HSS.

Overread · Oct 20, 2017

Sounds like good standard advice - the TTL advice certainly sounds like he's aiming it at fill lighting and some dominated in dynamic situations (ergo when covering an event rather than in a studio).

You don't have to leave HSS on if you don't want to; if you've got it on all the time then its there for you when you need it, but you can flick it on/off as you desire. The advice in the video certainly sounds like he's pitching it far more toward event shooting where you're only partly (or not at all) in control of a scene and where you and the flash might be mobile - ergo things are changing a fair bit and whilst you can use manual controls; you'd have to slow down and take test shots and in a dynamic event you're not going to have time for that. So his advice is pretty spot on for a constantly changing situation.

TonyUSA · Oct 20, 2017

[QUOTE=" It also becomes rather tricky for action because any fast motion is going to show blur as it catches the haze in the series of flash shots instead of a single action stopping pulse of light.[/QUOTE]

This always confused me. Somewhere on youtube said the same as your explanation above for fast action. And other just used HSS for fast action such as mountain bike. I think I watched both on youtube from Profoto B1 flash.

Overread · Oct 20, 2017

I just realised that I was an idiot!

Highspeed sync even on action should be ok so long as the flash is only contributing to brightening of shadows - ergo only for fill lighting. Ergo where without it the subject would be shadowed, but still rendered sharp.

Highspeed sync fails when you're trying to use flash to dominate the light for the scene; ergo where without it you'd have a very dark or fully underexposed photo. In this situation you're more likely to see the edges created by the pulses of light because each pulse is contributing the most light to that being recorded by the sensor.

I kind of meant that in my earlier post but seriously worded it wrongly and jumbled the two stances of fill and dominant up. HSS is oft used in action for fill lighting -eg bird photographers will use it with better-beamers (focuses the light to increase the amount falling on the subject - reduces light loss) for fill lighting when shooting wildlife.