Hi Henry,
you see the flourescent tube pictures on my homepage: This is
conventional ballast. When using an electronic ballast you would not see
any light modulation at all in the pictures.

You need to make 10-30 pictures of the lamp, because you will only by
chance hit the right time. Then take the brightest and darkest of them.
Sarina
> 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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Sarina Wunderlich
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91058 Erlangen
Tel: 09131 - 933 42 09
Mobil: 0173 - 68 57 191
mail: sarina_wunderlich@...

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