474 Full Power Pops! No kidding!

PacAce wrote in post #11629205
So why would the sync speed need to drop as the flash duration is decreased? That's a real mind boggler?

My guess is it has something to do w/ the default TT delay...remember that they can do pseudo HSS w/ studio strobes. They sort of hack this by delaying the receiver sync pulse into the tail end of the flash strobe pulse because they can intercept the camera's "get ready to fire" and "fire" TTL signals.
The einstein doesn't have a flash strobe pulse tail at faster durations, so whatever their default delay is, it's too long...sounds like they pulled it in w/ the latest firmware...

kenyee wrote in post #11631497
My guess is it has something to do w/ the default TT delay...remember that they can do pseudo HSS w/ studio strobes. They sort of hack this by delaying the receiver sync pulse into the tail end of the flash strobe pulse because they can intercept the camera's "get ready to fire" and "fire" TTL signals.
The einstein doesn't have a flash strobe pulse tail at faster durations, so whatever their default delay is, it's too long...sounds like they pulled it in w/ the latest firmware...

I'm pretty sure it's the PW remotes also but the Einsteins function similarly to hotshoe flashes and you don't see hotshoe flashes having the same issue where the shutter speed needs to be dropped 1/100 at lower power levels. And remember, we're talking about shutter speeds that are at or below max sync speed of the camera so HSS or HyperSync shouldn't even enter into the picture. The only other thought I had about it is the 2nd curtain sync that is turned on by default.

Maybe Dave or Eric can try the test again with 2nd curtain sync turned off and see what happens.

PacAce wrote in post #11631645
you don't see hotshoe flashes having the same issue where the shutter speed needs to be dropped 1/100 at lower power levels

Because the hotshoe flashes understand the TTL command signals.
The Einstein has no such thing. It's purely a programmable delay which you can configure in the TT config app on your PC...

kenyee wrote in post #11632058
Because the hotshoe flashes understand the TTL command signals.
The Einstein has no such thing. It's purely a programmable delay which you can configure in the TT config app on your PC...

Even when the flash is not mounted in the hotshoe of the FlexTT5 or when I have a non EX flash sitting in the hotshoe?

PacAce wrote in post #11632224
Even when the flash is not mounted in the hotshoe of the FlexTT5 or when I have a non EX flash sitting in the hotshoe?

yes, because the TT transmitter itself understand TTL...it reads this stuff out of your camera's hotshoe and it relays it to the TT receiver. That's why they took so long to release the Nikon version...it's not a simple thing to reverse engineer the TTL protocols...

kenyee wrote in post #11633035
yes, because the TT transmitter itself understand TTL...it reads this stuff out of your camera's hotshoe and it relays it to the TT receiver. That's why they took so long to release the Nikon version...it's not a simple thing to reverse engineer the TTL protocols...

Then why aren't the hotshoe flashes having the same problem as the Einstein? Or, to rephrase that, why is the Einstein having this issue when the hotshoe flashes, whether EX or not, are not? That's the point I was trying to make.

PacAce wrote in post #11633449
Then why aren't the hotshoe flashes having the same problem as the Einstein? Or, to rephrase that, why is the Einstein having this issue when the hotshoe flashes, whether EX or not, are not? That's the point I was trying to make.

As I mentioned, because the hotshoe flashes understand TTL timing and the Einstein or any studio strobe does not (if you hook it to a high end Broncolor pack which uses the same power quenching technique the Einstein does, I'd wager you'd have the same issue)...

kenyee wrote in post #11633662
As I mentioned, because the hotshoe flashes understand TTL timing and the Einstein or any studio strobe does not (if you hook it to a high end Broncolor pack which uses the same power quenching technique the Einstein does, I'd wager you'd have the same issue)...

Looks like we're just going around in circles here. This is the same answer you gave in post #33. So, please explain how any flash, even those without the 4 extra pins that the EX flashes have, can understand TTL timing whereas the strobes can not. And please don't repost post #35.

PacAce wrote in post #11634359
So, please explain how any flash, even those without the 4 extra pins that the EX flashes have, can understand TTL timing whereas the strobes can not

ok, now you have me confused. Exactly which flashes are you talking about? I had assumed that since you were talking about the PW TT, you were using official Canon-compatible flashes that support e-TTL...
If you mean generic flashes that have only the sync pin and nothing else, then my explanation makes no sense and I have no answer...

kenyee wrote in post #11634680
ok, now you have me confused. Exactly which flashes are you talking about? I had assumed that since you were talking about the PW TT, you were using official Canon-compatible flashes that support e-TTL...
If you mean generic flashes that have only the sync pin and nothing else, then my explanation makes no sense and I have no answer...

OK, now we're on the same page.

For all I know, you could very well be right. And if so, I'd like to know why the Einstein is affected but not an ordinary manual hotshoe flash.

As a disclaimer, I do not know for a fact that ordinary hotshoe flashes are NOT affected. I just haven't heard anybody complain about it. But I'll see for myself if they are or aren't since I have a couple of Control TL remotes and a couple of ordinary hotshoe flashes.

I just did a test with a YN560 and TT5. At full power and at min power the full frame was exposed. No shutter interference.

With the Einstein I have the same situation as Dave and the other poster experienced. Full frame exposed at full power, black bar with gradated edge on top of frame at min power with shutter at 1/200 didn't get full frame until 1/100.

Since its at the top of the frame that means the first curtain is not getting out of the way when the flash goes off right? My ControlTL stuff has the factory defaults for the Hyper Sync off set. That means its firing the monolight 170 Milliseconds before the curtains actually open.

According to the back panel on the Einstein, the T.1 duration is 1/8000 at minimum power. I wonder if that means the flash duration is so short that it can't fill in where the first curtain was in the way because of the pre-fire.

dmward wrote in post #11635197
I just did a test with a YN560 and TT5. At full power and at min power the full frame was exposed. No shutter interference.

With the Einstein I have the same situation as Dave and the other poster experienced. Full frame exposed at full power, black bar with gradated edge on top of frame at min power with shutter at 1/200 didn't get full frame until 1/100.

Since its at the top of the frame that means the first curtain is not getting out of the way when the flash goes off right? My ControlTL stuff has the factory defaults for the Hyper Sync off set. That means its firing the monolight 170 Milliseconds before the curtains actually open.

According to the back panel on the Einstein, the T.1 duration is 1/8000 at minimum power. I wonder if that means the flash duration is so short that it can't fill in where the first curtain was in the way because of the pre-fire.

Ah ha! That's where I thought it would have to be because it wouldn't make sense if it were at the bottom of the frame. So, it looks like Kenyee could be right after all in that it is the timing of the sync trigger.

David, if you have a spare moment, can you advance the sync timing of the Tx unit to 0 and see if that improves the sync?

dmward wrote in post #11635197
I just did a test with a YN560 and TT5. At full power and at min power the full frame was exposed. No shutter interference.

With the Einstein I have the same situation as Dave and the other poster experienced. Full frame exposed at full power, black bar with gradated edge on top of frame at min power with shutter at 1/200 didn't get full frame until 1/100.

Since its at the top of the frame that means the first curtain is not getting out of the way when the flash goes off right? My ControlTL stuff has the factory defaults for the Hyper Sync off set. That means its firing the monolight 170 Milliseconds before the curtains actually open.

According to the back panel on the Einstein, the T.1 duration is 1/8000 at minimum power. I wonder if that means the flash duration is so short that it can't fill in where the first curtain was in the way because of the pre-fire.

Looks like you've hit the nail squarely on the head, David!

With the sync timing set to -170, the flash/strobe is triggered 170 microseconds before the 1st curtain reaches the bottom of the frame (or at least before the moment when "normal" sync would trigger). So, when the flash goes off, all but the little section at the bottom of the frame is lit. 1/8000 is 125 microseconds. So, after the initial flash, the flash light lingers for another 125+ microseconds as the 1st curtain is moving towards the bottom of the frame. This is what causes the gradual shading to black at the bottom of the frame (i.e. the top part of the image if viewing the resulting image).

PacAce wrote in post #11635310
...David, if you have a spare moment, can you advance the sync timing of the Tx unit to 0 and see if that improves the sync?

The OTHER David advanced the sync timing:

Dave,
What about at minimum power?
That's where the problem was showing itself.
At full power there is enough tail to take care of things apparently.
With the YN560s at full power I can get past the nominal sync speed because of the long tail.
That's the big difference between speedlites, Einsteins and monolights. The IGBT circuit cuts off the tail to control flash power.

Set the TT1 and TT5 to Zero off set. Still had the dark band at the top. There was some light in the band not completely black again same until 1/100 when everything is lit. Einstein at minimum power.

Did a bit more testing. Can't figure out for sure what is making the shutter curtain shadow appear, but I did figure out why 1/100 second shutter speed gets rid of it.
That's the speed when the PW activates rear curtain sync. I changed the speed to 1/30 and the shutter shadow was there until 1/30 then disappeared. It didn't make any difference where the off set was -170 or Zero.