HSS and Flash Meters

[rpcrowe]

I have just watched a Gavin Hoey YouTube video on HSS.

https://www.youtube.com/watch?v=jywWCwvf7ps

He states that his flash meter will not work when the flash is in HSS mode. I wonder what meters will work in HSS?

[Dave Humphries]

Have you seen?

Flash-havoc: Sekonic L-858D
Sekonic: Sekonic L-858D

Only problem might be the $599 price tag and that might not be all you'd want; depending upon your powering and remote triggering desires.

It does look very smart though!

Cheers, Dave

[rpcrowe]

Actually, I don't use manual HSS that often to pay a premium price for a meter. "Guestimation", is just fine with me.

I get along just fine with my old, bare bones, Sekonic L-718 meter. The manual doesn't say anything about HSS so, I expect that it doesn't work with High Speed Sync. OTOH, I should try it out to see if there is a way to make it work...

[Dave Humphries]

I get along just fine with my old, bare bones, Sekonic L-718 meter. The manual doesn't say anything about HSS so, I expect that it doesn't work with High Speed Sync. OTOH, I should try it out to see if there is a way to make it work...

It won't.

If you google "flash meter HSS" as I did, you'll possible find the same forum thread where folks were tabulating exposure offsets to allow them to use their legacy meters with HSS.

While your meter isn't the same model, likely the offsets will be similar - to within guestimation range anyway

[george013]

It won't.

If you google "flash meter HSS" as I did, you'll possible find the same forum thread where folks were tabulating exposure offsets to allow them to use their legacy meters with HSS.

While your meter isn't the same model, likely the offsets will be similar - to within guestimation range anyway

I think you can calculate the loss of flash light by the ratio sync time and shutter speed.

The flash time is expanded over the total curtain movement or 2xsync time. When you shoot at sync time in HSS mode, you loose 50% to start with. Shooting with 1/500 and a sync time of 1/250 will result in a loss of 75%.

Maybe somebody may check those figures. But I think a flash meter that calculates the desired output in HSS does the same calculations. It has to know the shutter speed, either from the camera or from an input on the meter itself.

George

[Manfred M]

It has to know the shutter speed, either from the camera or from an input on the meter itself.

Hand-held flash meters that I have used are not connected to the camera, so there is no direction communication between the devices. They do require the shutter speed to be input as they have to assess the ambient light as well as the light from the flash.

For a meter that is used for HSS, the synch speed would also be required as this would form an important input on the distance between the two shutter curtains. As well, synch speed does vary; I have cameras with synch speeds as low as 1/90th sec and as high as 1/250th sec.

If one gets into the high end medium format cameras with leaf shutters built into the lenses, the synch speed will be even higher. I see Phase One cameras with leaf shutters giving 1/1600th sec shutter speed and Hasselblad is showing 1/2000th sec synch speed with leaf shutter lenses.

[george013]

Hand-held flash meters that I have used are not connected to the camera, so there is no direction communication between the devices. They do require the shutter speed to be input as they have to assess the ambient light as well as the light from the flash.

For a meter that is used for HSS, the synch speed would also be required as this would form an important input on the distance between the two shutter curtains. As well, synch speed does vary; I have cameras with synch speeds as low as 1/90th sec and as high as 1/250th sec.

If one gets into the high end medium format cameras with leaf shutters built into the lenses, the synch speed will be even higher. I see Phase One cameras with leaf shutters giving 1/1600th sec shutter speed and Hasselblad is showing 1/2000th sec synch speed with leaf shutter lenses.

Yes, the sync speed must be known to by the meter.

In my calculation I did put the time the curtains move at 2xsynctime. That counts only for the sync time. More exactly it would be sync time + shutter speed time. I don't know what the flash is doing. When reading the practical results of the link been given here before, I don't think it does adjust that time.
It's just important to get an idea of what's going on. And how roughly work with it.

George