the thing is:
an authority vet asked me:

chicken farmers pretend to use electronic ballasts with their
fluorescent lamps
but have electromagnetic ballasts. so there is a flicker stress to the
animals.
is there an easy way to convince them with photos that there is a
visible flicker to
there hens which implements stress with digicam fotos?

gx henry

Sarina Wunderlich schrieb:
>
>
> Hi Henry,
> > is there a trick to guess and visualize the flicker rate of lamps with
> > the digicam?
> >
> What do you want to vizalize? The flicker frequency is known in all
> lamps, it is always the double of the operation frequency. If the
> operation frequency is not 50Hz (as in lamps with electronic ballasts,
> the operation frequency is given in the manual) the light intensity is
> additionally modulated with 100Hz.
>
> The only thing that is unknown is the modulation depth: How dark does
> the lamp get.
> You can vizualize this by taking fotographs of the lamp with exposure
> time 1/1000 sec and fixed aperture and iso.
> See fotographs here:
> http://www.testudolinks.de/lichtwiki/roehre/flackern
> <http://www.testudolinks.de/lichtwiki/roehre/flackern>
> and here: http://www.testudolinks.de/lichtwiki/hql/flackern
> <http://www.testudolinks.de/lichtwiki/hql/flackern>
>
> But Reptiles won't see flicker when you don't see it. I found no
> evidence that their flicker sensitivity is better than ours. See here:
> http://www.testudolinks.de/lichtwiki/vis/flicker
> <http://www.testudolinks.de/lichtwiki/vis/flicker>
> The website is only German, but klick on the [number] and you will be
> forwarded to the original scientific article in my literature database,
> all of them are in English
>
> Sarina
>
>

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