Continuous Florescent Lighting

On Wed, 19 Dec 2007 09:52:34 -0800 (PST), Scott W <biphoto.RemoveThis@hotmail.com>
wrote in
<1941a3b9-d4a9-4795-bade-bdc0aed1d01d.RemoveThis@d27g2000prf.googlegroups.com>:

>On Dec 19, 6:38 am, John Navas <spamfilt....RemoveThis@navasgroup.com> wrote:
>> On Wed, 19 Dec 2007 09:42:03 -0600, George Kerby
>> <ghost_top....RemoveThis@hotmail.com> wrote in
>> <C38E97EB.45CC0%ghost_top...@hotmail.com>:
>>
>> >On 12/18/07 7:51 PM, in article r1ugm3918kblq3u85n4dren0p50cd4g....RemoveThis@4ax.com,
>> >"John Navas" <spamfilt....RemoveThis@navasgroup.com> wrote:
>> >> Can you name even one HD camera with the shutter speeds of a simple
>> >> compact camera?
>> >http://www.abelcine.com/store/product.php?productid=1000189
>> >http://www.schumachercamera.com/cameras.htm
>>
>> In other words, you can't. Thanks for proving my point.
>
>He shows you a HD camera with shutter speeds as fast as 2 micro
>seconds, just how fast is your compact camera?

I was referring to standard broadcast cameras -- apples and apples, not
apples and ice cream.

>And was does shutter speed have to do with it anyway?

Flicker and strobing, which generally aren't problems with the frame
rate of broadcast TV, but can be a problem in still photography,
depending on light frequency and shutter speed.

>The biggest problem with fluorescent lights is that most have odd
>spectrum, a blue peak and a wide yellow area, but not much in the red
>or green areas. They also tend to go bluer as they age. ...

It all depends on the phosphors, but even with balanced phosphors, the
phosphor color peaks tend to cause color shifts in critical still
photography that aren't an issue in broadcast TV.

--
Best regards,
John Navas
Panasonic DMC-FZ8 (and several others)
 >> Stay informed about: Continuous Florescent Lighting 

On Dec 19, 6:46 pm, John Navas <spamfilt... RemoveThis @navasgroup.com> wrote:
> On Wed, 19 Dec 2007 09:52:34 -0800 (PST), Scott W <biph... RemoveThis @hotmail.com>
> wrote in
> <1941a3b9-d4a9-4795-bade-bdc0aed1d... RemoveThis @d27g2000prf.googlegroups.com>:
>
>
>
>
>
> >On Dec 19, 6:38 am, John Navas <spamfilt... RemoveThis @navasgroup.com> wrote:
> >> On Wed, 19 Dec 2007 09:42:03 -0600, George Kerby
> >> <ghost_top... RemoveThis @hotmail.com> wrote in
> >> <C38E97EB.45CC0%ghost_top...@hotmail.com>:
>
> >> >On 12/18/07 7:51 PM, in article r1ugm3918kblq3u85n4dren0p50cd4g... RemoveThis @4ax.com,
> >> >"John Navas" <spamfilt... RemoveThis @navasgroup.com> wrote:
> >> >> Can you name even one HD camera with the shutter speeds of a simple
> >> >> compact camera?
> >> >http://www.abelcine.com/store/product.php?productid=1000189
> >> >http://www.schumachercamera.com/cameras.htm
>
> >> In other words, you can't. Thanks for proving my point.
>
> >He shows you a HD camera with shutter speeds as fast as 2 micro
> >seconds, just how fast is your compact camera?
>
> I was referring to standard broadcast cameras -- apples and apples, not
> apples and ice cream.
>
> >And was does shutter speed have to do with it anyway?
>
> Flicker and strobing, which generally aren't problems with the frame
> rate of broadcast TV, but can be a problem in still photography,
> depending on light frequency and shutter speed.

Fluorescent lights operate in the range of 40KHz, not much of a
flicker problem with these. I would hope any that are going to be
used for photography would be of this type.

Scott
 >> Stay informed about: Continuous Florescent Lighting 

In article <4767046d$0$2491$4c368faf@roadrunner.com>,
sligoNoSPAMjoe.RemoveThis@hotmail.com says...

> The problem then and now is that word "continuous" Continuous in one
>respect is great and that is one reason we liked them They did not flash,
>they just stayed on all the time.


The really huge problem with continuous light is that the camera shutter is
NOT continuous. The shutter is only open a very brief instant, for example
perhaps 1/100 second, which does not let much continuous light in.

The classic 500 watt photo flood lamp... 17000 lumens.

But the unit of energy is lumen seconds.
Definition: If on for one second, then this is 17000 lumen seconds.

But if the camera shutter is 1/100 seconds, then:
17000 lumens x 1/100 second = 170 lumen seconds usable.
500 watts x 1/100 second = 5 watt seconds usable.

A small studio flash (160 watt seconds) may be rated 7000 lumen seconds

With one, we turn it down to 1/4 power, and shoot at ISO 100 at f/11 and
maximum shutter sync speed.

With the other, we set ISO as high as we can bear, and we struggle to place
the lights up as close as we can bear, to try to shoot portraits at 1/60
second with lens wide open. And we sweat in the heat it generates. Heat is
continuous too.

OTOH, if shooting inanimate product work, we can use a 1/2 second shutter,
which captures 6 stops more light than at 1/125 second. Just is not a very
suitable speed for portraits of humans.
 >> Stay informed about: Continuous Florescent Lighting