Such check via audio method


robert mcafee
 

It would be interesting to place a microphone between the 2 cameras and record the "shutter" sounds. With the Samsungs I believe you can choose to turn on of off a audible shutter indication.  Recording the sound of the 2 cameras being triggered we should be able to see the peaks in the wave form from each of the cameras and measure the time difference between these shutter sounds.  Of course this assumes no delay between actual "shutter" activation and the digital sound for same or at least we must assume any delay between shutter and sound is the same for both cameras (may not be true).

My laptops all came with some software for displaying and some editing of wav files and there are free programs available


On Sun, Sep 6, 2020 at 2:57 PM, Bill Costa
<Bill.Costa@...> wrote:
> Correct. So if the NX1000 are powered on too close together (in
> time) one of the cameras does not detect the attached remote
> control.

I just tested this today (for the first time) and found...

1) Successful Finger Sync power-on; external trigger works reliably.

2) Unsuccessful Finger Sync power-on; one of the cameras will not
    respond to the external trigger. Let's call this a "sync-jam".

3) Delayed power-on sequence, approx 1 second (or more); external
    trigger works reliably.

With an Unsuccessful Finger power-on (2), you can hear that both
switches were not activated simultaneously -- two distinct but closely
spaced clicks.  But when I am able to successfully make it sound like
both switches were activated as a single click, then the external
trigger never failed.

BTW -- at no point did I have to disconnect the cameras.  Just turning
them both off was sufficient to clear any sync-jam.

CAVEAT: My external trigger has isolating diodes for both the focus
and shutter circuits.  Your mileage may vary.

> This would be the case if cameras are simultaneously powered on via
> a battery adapter with an external power switch.

I would guess that a sync cable that provided a true simultaneous
power-on would avoid sync-jam with these cameras.  But it is my
opinion that creating such an NX1000 rig is unlikely to be worth the
effort.  Here's why I believe this...

With successful finger sync power-on (1), I noticed that the first
time I focus, both cameras almost always confirm the focus at the same
time (beep at the same time).  In contrast, if I stagger turning on
the cameras, there is almost always a significant mismatch in the
focus-ready beep for the *first* focus attempt.  So the simultaneous
power-on does indeed seem to have some effect with the NX1000 cameras.

However in either case, I cannot hear any difference in the sync of
the shutters when triggered.  Further more, while the first focus may
be out of sync, all of the subsequent focus attempts are in-sync, or
very very close.  [tested using multi-point focus setting]

Unfortunately I do not currently have a way of quantifying the degree
of shutter sync on my NX1000 rig.  But using the sound of the cameras
should not be ignored for determining the relative quality of the
shutter sync.  "For auditory sensations, a crackling sound is
identified at a separation of about 1 ms between very brief stimuli,
while a discontinuity requires lO ms." [PF84].  So even if
simultaneous power-on does improve the sync, the improvement is
somewhere in the neighborhood of 10 ms or less.  For me personally I
would not go to heroic efforts to power-sync NX1000 cameras unless it
could be demonstrated with actual measurements that a real benefit in
sync can be achieved.

Bottom Line: I only worry about sync in terms of motion induced
"retinal rivalry", a problem I can't recall ever seeing in photos from
my NX1000 rig.

Note: With my sync cable built-into my pistol grip, I hold the rig by
the pistol grip in one hand, and then sequentially turn on the cameras
with the other.  So there is consistently about a one second delay
between each power-on.  This must be why I don't recall ever having a
sync-jam problem with my rig.  For testing I had to put the rig on a
tripod so I could do the finger-sync power-on tests described above to
induce a sync-jam.

...BC

[PF84] https://www.annualreviews.org/doi/pdf/10.1146/annurev.ps.35.020184.000245



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