a couple 1x1 LED panels compared

[Michael Morlan]

Hi all,

 

It's been a great while since I've posted so I thought I'd contribute something.

 

A lot of people are enthralled with the new era of LED lighting and, in the lower-end market segment, with the Asian knockoffs of pricey U.S. products. I've scanned a variety of reviews but have not found the kind of data or insight I seek as a DP. So, of course, I did some of my own testing...

 

I tested the Lightpanels 1×1 Superspot and Shantou Nanguang CN-600HS 1×1 panel. My goal with this test was to see how a $350 Chinese knock-off compares to the nearly $2000 U.S. offering and to compare both panels to a tungsten Lowel 250watt Pro-light serving as a reference.

 

1x1 panels tested

 

Enjoy,

 

Michael

[Eric Jaspers]

A lot of people are enthralled with the new era of LED lighting and, in the lower-end market segment, with the Asian knockoffs of pricey U.S. products. I've scanned a variety of reviews but have not found the kind of data or insight I seek as a DP. So, of course, I did some of my own testing...

 

The Academy of Motion Picture Arts and Sciences (AMPAS) conducted very similar tests of LEDs as part of their “Solid State Lighting Project Technical Assessment.” For a good objective 3rd party analysis of AMPAS’ comparison of LED fixtures I would suggest the following article on LEDS.

 

To summarize this article: when it comes to LED lights, you get what you pay for. The reason Litepanels are more expensive than say the Cool Lights or the Shantou Nanguang CN-600HS 1×1 panels is that they are a better made light. For instance the linear voltage regulator that Cool Lights uses in their heads to stabilize the LED current has several drawbacks in comparison to the approach that Litepanels uses which is a DC-to-DC switched-mode power supply (SMPS) in conjunction with a constant current regulator in the light head. The first drawback to the Cool Light’s approach is that considerable energy is wasted in the series resistors. Second, the linear voltage regulator that converts the supply voltage to the desired voltage for the LED strings maintains a constant output by wasting excess electrical energy by converting it to heat. As such, this approach is highly inefficient and not ideal for battery operation. The same function is performed more

efficiently by using a DC-to-DC switched-mode power supply (SMPS) like the one Litepanels uses in conjunction with the constant current regulator they build into their light heads.

 

Another big difference is in the color output of the LEDs used in the two heads. Litepanels uses much more stringent parameters in the binning process so the color output of their heads is more accurate and consistent between heads. But, even with more stringent binning the approach that both Litepanels, Cool Lights, and Shantou Nanguang take to generating white light with LEDs – Phosphor White Technology - has an inherent limitation: by their nature the spectral distribution of Phosphor White LEDs is less than optimum for motion picture lighting applications (use this link for details.)

 

While they are less than perfect at reproducing parts of the color spectrum, the color rendering of Phosphor White LEDs may be adequate in certain situations. For a specific application, say where lights must be operated off of batteries, a LED fixture offers the unique advantage of greater power efficiency over conventional lights, which may out weigh its shortcomings in color rendering. However, a Phosphor White LED, as Michael point out, is clearly not the best choice in applications where color rendition is critical (food/product shots) or mixed with a uniform continuous light source, such as a studio lit with tungsten fixtures, where its color deficiencies will be quite noticeable and unacceptable in comparison (see this thread for more details..)

 

- Eric Jaspers

[Michael Morlan]

Excellent addition to the thread, Eric. Agreed on all points.

 

I find I'm willing to use LED sources on non-critical elements; raking a set piece, as a hair light, and, yes, even to light talent in a run-n-gun, realism setting. But, I'd avoid them entirely when lighting for glamor or for rendering subtle details of certain colors and textures.

 

M