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Re: [OM] You know what I miss?

Subject: Re: [OM] You know what I miss?
From: Michael Gordon via olympus <olympus@xxxxxxxxxxxxxxxxx>
Date: Mon, 5 Jan 2015 22:54:39 -0500
I have no EE experience nor led construction.  I suppose the phosphors like yAG 
( to add yellow) are glommed onto the top of a standard high efficiency blue 
led to extend the spectrum.  Even adding another phosphor still results in a 
discontinuous emission spectrum which can confound proper color balance on film 
or digi sensors.
Mike


On Jan 5, 2015, at 10:05 PM, Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx> 
wrote:

> Dr. Flash asks: What are compensating phosphors?  Not the definition but 
> describe the physical hardware.
> 
> Dr. Flash
> 
> 
> On 1/5/2015 7:13 PM, Mike Gordon via olympus wrote:
>> Dr. No Flash fan writes:
>> 
>> <<I am likely no never buy another flash, but will transition
>> <<to LED panels instead.
>> 
>> 
>> tungsten on left, "white" LED with compensating phoshors on right.
>> 
>> http://www.screenlightandgrip.com/images/generators/LED_Model_Comp.jpg
>> 
>> Loss of cyan balls up the dress rendition.
>> 
>> http://www.screenlightandgrip.com/images/generators/LED_Effect_on_Skin_Color.jpg
>> 
>> 
>> Skin renditon upset by steep drop off in long wavelength light---if the
>> color is not in the light  it can't be reflected at all.  This  can make
>> it very  difficult to fix in post even shooting a target.
>> 
>> I don't know how long it takes the phosphor light to decay but suspect
>> dramatically longer than usual strobe thus no help stopping motion
>> for macro flash with critters. If using continuous LED light though, no
>> worry about sych speed and can bump up shutter speed to a degree.
>> 
>> Bottom line--unless the phoshors have improved (perhaps they have)  not
>> sold on LED.  Suspect the manufacturers just  might be spinning the
>> data on the LED panels.  I bet Tim knows the scoop on this.
>> 
>> Student of Dr. Flash, Mike
>> 
>> 
-- 
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