Re: Potential shutter speed problems

[P3D Marcus Warrington <marcus@xxxxxxxxx>]

Gabriel writes :

> Okay I don't have more electronics knowledge, so that's why I try to
> be resourcefull instead! I don't know how accurate this would be, but
> I have noticed when shooting pics (higher than 1/30, most likely),
> with the TV in the background, the scan lines (from the TV screen) are
> visible in the photograph. It would seem to me that if the shutter
> sync was off, the scan lines would not match in the left and right
> images.

Funnily enough I was thinking of a similar technique for testing shutter 
synchronisation by taking a stereo shot of a revolving record (does anyone else 
still have a record deck.. or am I showing my age) with a white line painted 
across it. You could then compare the two shots to see if the line was in the 
same degree of rotation in both shots.
 
> I notice this when I shoot pictures with my twin P&S, but surprisingly
> the scan lines are only an inch or two displaced from each other most
> of the time.

doen't sound too suprising , or am I missing the point ? Since each scan 
(field) is 1/60 (for you NTSC guys, 1/50th for us PAL guys) of a second i.e. 
the two interlaced fields take 1/30th to display = 30 frames a second. Then 
regardless of the point at which you fire the shutters they can only ever by a 
maxium of 1/60th of a second apart in terms of the relative postition of the 
scan line.
 
> P.S. What kind of dog is in your stereo picture. (and don't tell me it's
> an ascii dddog! ;-)

Ok.. its NOT an ascii dddog :)

.. its a mongrel :)

Marcus ?8^)
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