[photo-3d] Re: Twinning (Digest 412)

[JNorman805@xxxxxxx]

Jay writes:

<< Question to all: Is it better to match apertures or shutter speeds? I've 
got
a couple of Canon EOS IXs (APS SLRs) linked together with a cable that I
made by splicing the cables from two Canon RS-60E3 wired remotes together.
I'm probably wrong, I'm fairly new to 3-D, but I figured it was probably
more important to have matching shutter speeds. I figured the apertures
would either end up being same/close to the same, or that I could attempt to
correct over/under-exposure PhotoShop. Not sure what I could do about the
"action" not being in sync with differing shutter speeds! What is everyone
else doing to sync their SLRs? >>


I've got two Canon EOS SLRs wired together in much the same fashion, and if 
I'm not using flash I always set the cameras to aperture priority so that my 
chosen apertures and the resulting depths of field are an exact match.  I've 
noticed that the shutter speeds do in fact sometimes vary, but if I use 200 
or 400 speed film under normal daylight circumstances, the shutter speeds are 
fast enough so that even if they do not match they are both quick enough to 
stop waving flags, splashing water, etc.  I don't know how you could use 
photoshop to clean up the focus blur differences that might be caused by 
mismatched depths of field.  As an alternative, if I'm shooting in extremely 
odd circumstances that I know from the outset will tend to be problematical 
for either or both cameras, I use one camera to meter the scene under 
representative circumstances, then set both cameras to full manual so that I 
know the shutter speeds and the apertures will be the same.  Also, if I know 
from the outset that the subject will tend to make the autofocus on one or 
both cameras "hunt" for a time before settling in, I set the lenses to manual 
focus as well.  An example that comes to mind is the scene that taught me all 
about the shortcomings of auto-everything cameras:  trying to shoot from 
inside a flock of swirling pigeons.  It didn't work at all on full auto, and 
it didn't work on manual exposure and autofocus.  It worked technically on 
full manual, but I haven't yet come up with a composition that I think is 
worth a damn, so I'm still trying!  By the way, if you use flash with this 
arrangement, an off-camera single flash (not those built-in flashes on the 
cameras), and manual exposure with a shutter speed slower than the stated 
sync speed are absolutely imperative, in my experience.

Jim Norman


[Non-text portions of this message have been removed]