That's a better summary than the one that I found. Thanks!
Jim Nichols
Tullahoma, TN USA
On 12/6/2015 2:34 PM, Chuck Norcutt wrote:
I think you are correct but the operation of a sodium vapor lamp is
not as simple as we might have guessed. From wiki
--------------------------------------------------------------------------
In practical use, the lamp is powered by an AC voltage source in
series with an inductive "ballast" in order to supply a nearly
constant current to the lamp, rather than a constant voltage, thus
assuring stable operation. The ballast is usually inductive rather
than simply being resistive to minimize resistive losses. Because the
lamp effectively extinguishes at each zero-current point in the AC
cycle, the inductive ballast assists in the reignition by providing a
voltage spike at the zero-current point.
-------------------------------------------------------------------------
Chuck Norcutt
On 12/6/2015 1:46 PM, Jim Nichols wrote:
Chuck,
I may be wrong, but I see 4 images.
1/30 sec times 60 cycles equals 2 captured cycles, giving 4 peaks.
This assumes that the light fires on both + and - peaks.
Jim Nichols
Tullahoma, TN USA
On 12/6/2015 12:27 PM, Chuck Norcutt wrote:
Check the wheels. I think there are only 2 images. 60Hz at 1/30 sec.
Chuck Norcutt
On 12/5/2015 11:05 PM, Jim Nichols wrote:
Michael and Philippe,
Note the multiple images of some details in this Winter scene under a
sodium vapor street light. Though not visible to the eye, the flicker
of the light produced multiple images of the moving car.
http://www.gallery.leica-users.org/v/OldNick/Snow+by+Street+Light.jpg.html
Jim Nichols
Tullahoma, TN USA
On 12/5/2015 3:59 PM, Philippe wrote:
I presume you'll get that rolling shutter effect if you set the
X-T1's
to electronic ;-)
Chronophotography due to the "beam" scanning the surface.
Look at the bike in this handheld pano shot using a high rate burst
(may be viewed large), same cause i.e. time discrepancy between
various parts of the image.
http://gallery.leica-users.org/v/Phileica/Playground/WW-Gruyeres+Caterpillar+Bike.jpg.html
;-)
Amities
Philippe
Le 5 déc. 2015 à 08:03, ChrisB <ftog@xxxxxxxxxxxxxx> a écrit :
They are good fun, those photos, Mike. My students sometimes get
that effect in our little moped-of-the-skies when they shoot forward
with their (normally) iPhones.
Chris
On 5 Dec 15, at 00:00, Michael R. Collins
<MRC.OlympusList@xxxxxxxxxxxxxxx> wrote:
Here's a Metroliner doing the same blade-throwing trick; not quite
as dramatic a picture. Can't remember the actual number of blades,
Bearskin fly some 5-blade and some 6-blade craft:
<http://zone-10.com/tope2/main.php?g2_itemId=19326
<http://zone-10.com/tope2/main.php?g2_itemId=19326>>
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