PW's syncing at 1/1000

1D and PW... a match made in heaven

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Interesting! At what shutter speed do you see the shutter creep in?

Im seriously tempted to get a 1D just for that reason. And I could stop carrying around my AB for outdoor shots.

tim wrote in post #7159886
Interesting! At what shutter speed do you see the shutter creep in?

As I understand the 1D uses an electronic shutter at these speeds so... never

Hey, where's the control experiment? Maybe skyports, cybersyncs, cactus, etc all can sync at 1/1000th?

Hermes wrote in post #7160061
As I understand the 1D uses an electronic shutter at these speeds so... never

Not so. I know someone (PacAce?) did some experimenting with a G series camera. The image just gets gradually darker as shutter speed increases past the point where it's catching the full duration of the flash.

40Dude6aedyk wrote in post #7160084
Hey, where's the control experiment? Maybe skyports, cybersyncs, cactus, etc all can sync at 1/1000th?

Credible tests I have seen, using split images lit partially by PC cord flash and partially by the radio system being tested, seem to reveal that the Skyports are a bit slower. The Cactus units are all over the map. I haven't seen similar tests done with Cybersyncs.

Curtis N wrote in post #7160183
Not so. I know someone (PacAce?) did some experimenting with a G series camera. The image just gets gradually darker as shutter speed increases past the point where it's catching the full duration of the flash.Credible tests I have seen, using split images lit partially by PC cord flash and partially by the radio system being tested, seem to reveal that the Skyports are a bit slower. The Cactus units are all over the map. I haven't seen similar tests done with Cybersyncs.

Thats's the point I was making, you won't see shutter creep (in the traditional sense). As for when the frame begins to darken, I found it to be around 1/1000 with a G9 and studio strobes but I certainly got to 1/1000 with skyports and no problems. I suspect that if I was using hotshoe flashes I could have got it shorter.

Hermes wrote in post #7160061
As I understand the 1D uses an electronic shutter at these speeds so... never

Just the original 1D, or all 1D-series cameras?

Also, why don't all cameras use an electronic shutter. What is the down side?

tim wrote in post #7159886
Interesting! At what shutter speed do you see the shutter creep in?

You don't. 1D shutter only opens at 1/500 max, everything faster than that is done by turning the CCD on then off. at 1/1250 it goes mostly black because it's not long enough for the flash duration, but you can see the flashtubes glowing haha.

XterraJohn wrote in post #7160360
Just the original 1D, or all 1D-series cameras?

Also, why don't all cameras use an electronic shutter. What is the down side?

Original 1D is the only Canon camera that you can do this with. On Noinks, however, both the D40 and the D70/D70s can sync high.

CCD's heat up quicker so you can't do 30 second exposures without a bunch of hot pixels... also most CCD sensors seem to yield less megapixels then CMOS.

40Dude6aedyk wrote in post #7160084
Hey, where's the control experiment? Maybe skyports, cybersyncs, cactus, etc all can sync at 1/1000th?

Cactus are so terribly unreliable. I could sometimes sync at 1/640, and then other days I'd be limited to 1/160. There's a reason why they're only $22... they suck. I could only get 1/640 indoors and within 20 feet. For around 2 weeks straight I could consistently hit 1/400. Never got to 1/500 consistently, though.

Curtis N wrote in post #7160183
Credible tests I have seen, using split images lit partially by PC cord flash and partially by the radio system being tested, seem to reveal that the Skyports are a bit slower.

I have done some on-camera-dummified-flash vs Skyports testing on a Nikon D70, which also has an electronic shutter. They sync reliably always at 1/800th, and (unless the batteries are worn down) also at 1/1000th, apparently without any impact on the exposure.

This is, however, only valid for "shorter" flash durations. I think that the Skyports cause a delay of just short of 1/1000th, from what I've been able to see/measure. The PW's are probably quite close to this, but a tad shorter.

For the OP that mentioned the flash wasn't fast enough at 1/1250th, I believe that may not be the only explanation. Modern flashes are really fast at low power levels. But as/if the radio system causes a delay of around 1/1000th-1/1250th, no matter how fast the flash is, it will stop appearing when your shutter speed gets faster than this.

So the PWs are, from what I have seen and been able to determine, faster than the Skyports, but not by an order of magnitude. I would be able to measure the Skyports (have and use those), but as I don't have any PWs I cannot first-hand verify those.


-- Per.

I had similar results with my cactus triggers. Last summer I could sync at 1/320 all day with no problems. Now, depending on what day I fire them up I get between 1/20 and 1/60th to sync. Not good. I have changed all the batteries too.

baekgaard wrote in post #7161806
So the PWs are, from what I have seen and been able to determine, faster than the Skyports, but not by an order of magnitude. I would be able to measure the Skyports (have and use those), but as I don't have any PWs I cannot first-hand verify those.

I just re-did my testing. The results show that my two Skyports add a sync-delay of 0.91 mS (~1/1100th of a second), with an uncertainty of around +/-0.01mS.

I tested this with my D300. By shooting a really short flash at shutter speeds between 1/250th and 1/4000th, the second curtain position can be determined quite precisely as a function of time. The shutter travel time (as I measured it) was 2.32 mS, which is almost the same value I have seen other people report.

By comparing shots of a directly mounted flash (only middle pin connected, so equal to PC sync socket test) and shots going through the Skyports, the delay can be calculated by comparing the time corresponding to the position of the curtains. There seems to be good repeatability in the tests I did.

If anyone would care, I can mail the spreadsheet and the images...


I don't have the PW, so I cannot test those. If anyone would like to have the delay calculated, and you have the PWs and a camera with a non-electronic shutter, let me know. I would just need two series of shots between 1/250th and 1/4000th: One series with a PC mounted fast electronic flash (usual minimal power) and one shooting the same flash though the PW.


-- Per.

baekgaard wrote in post #7164237
I just re-did my testing. The results show that my two Skyports add a sync-delay of 0.91 mS (~1/1100th of a second), with an uncertainty of around +/-0.01mS.

... found a couple of images in another thread. Using these made it possible for me to do a crude estimate of the PW sync-delay to be around 0.47 mS.

The implication of this in practice could be exemplified as follows: On a D300 (sorry -- the camera I'm mostly familiar with in this respect), the shutter travel time is 2.32 mS edge-to-edge. At 1/250th (external flash sync speed), the sensor is fully exposed by the first shutter curtain 0.20 mS before the flash is triggered. The 2nd curtain starts to travel accross the sensor 1.48mS (4mS - 0.2mS - 2.32mS) after the flash is triggered.

With on-camera or PC-sync (or optical trigger), there is no discernable delay, and the flash pulse (t0.1 time) can be as long as the full 1.48mS or ~1/625th before even minimal darkening can be noticed.

With a PW, the flash pulse needs to be shorter than 1 mS (1/1000th). With a Skyport, it must be shorter than 0.57mS (~1/1600th).

If the flash pulse is around 1/625th (like an electronic flash at maybe 1/2 power or less -- things like studio strobes can be ~1/250th at half power/t0.1 timing), you can shoot it with direct triggering w/o any darkening.

For the same flash length of 1/625th, you would have to drop your sync speed to 1/200th with either the PW or the Skyport (PW requires 1/220th and Skyports 1/203th). So in many practical situations, there will be no noticeable difference between the PW and the Skyports.

If your flash pulse is longer than 1/625th -- say 1/250th -- you would anyway need to go to a longer sync speed. On the D300, sync'ing a flash reliably with a cable connection when the flash pulse lasts 1/250th and you would like to see no darkening at all, would require you to shoot at 1/160th.

You would need to drop the speed to 1/125th with either PW or Skyport, but if you shoot at 1/160th you would likely get only minimal darkening -- possibly a tad less with the PW than the Skyports.

So bottom line might be: If you use small electronic (fast) flashes, you should drop your shutter speed a tad when using PWs or Skyports (like one click below x-sync in most cases, I think). If you're already below x-sync due to shooting with studio flashes (you probably should with many of the cheaper ones) you may be good to go at the same speed, but better drop one click again to be sure or if you cannot re-shoot (or at least check the image on the screen!).


-- Per.

epatt250 wrote in post #7162596
I had similar results with my cactus triggers. Last summer I could sync at 1/320 all day with no problems. Now, depending on what day I fire them up I get between 1/20 and 1/60th to sync. Not good. I have changed all the batteries too.

Yep, I dropped $15 on new batteries and that did absolutely nothing.