Monthly Archives: September 2014

LED Fresnel test

I have just bought 2 of the CE-1500WS LED Fresnel lights and put them through some basic tests for colour and flicker performance.

Size and Packaging

Each light comes well protected in shaped polystyrene in a cardboard box. The box measures 37 x 31 x 30cm. It comes with a cable to connect to the mains, a cable to connect two or more lights together (so several can be powered from just one mains socket), a remote control (which only turns the lights on/off, so it is of little real use), a tungsten balanced filter, a diffusing filter, a set of barn doors._MG_3204Interestingly, the filters are held in place with small magnets, which makes them very easy to use.

The light itself measures 36 x 30 x 27cm and weighs 5.3kg._MG_3200

The light can be focussed between 40°- 80° beam angle._MG_3202

Colour Temperature

No filter:

The specs claim the light is 5400K +/-200.

Red Epic footage shows a colour temp of 5000K, needing a tint of 17 (green) (in RedCine-X).

Canon 5D Mark II stills show a colour temp of 4500K, needing a tint of -58 (green) (in Adobe Camera Raw).

This means that there is a significant magenta colour cast with these lights.

_MG_3197-full-power

Dimming the light didn’t affect the colour temp significantly. At lowest power the colour temp was 4300K, measured with the Canon and ACR (as opposed to 4500K at full power)._MG_3198-dimmed

Tungsten filter:

The specs claim the light is 3500K +/-200.

Canon 5D Mark II stills show colour temp of 2850K, needing a tint of -20 (green) (in Adobe Camera Raw)._MG_3199-tungsten

Intensity

With the light 2m from the subject, the following settings were achieved:
ISO 100
1/80
f/3.2

Video Flicker

There was no apparent flicker, even at frame rates of 300fps!

The following video shows Red Epic footage shot at frame rates of 25, 50, 75, 100, 120 and 300 fps.

http://www.youtube.com/watch?v=OSeQd10JgbY

Fresnel or not?

The first thing I noticed was that despite the product description claiming it is a “Fresnel” light, the lens is not a fresnel lens. I wrote to the supplier pointing this out and they replied:

“[the manufacturer] admitted their lenses are not the same as photo showed on their official website. But they said this new lens performs better than the one with concentric ripples.”

They also said they would send me the fresnel lens, so when it arrives, I will repeat these tests [09 Oct 2014, fresnel lenses arrived in post, so additional tests are shown below]

_MG_3201

Not a fresnel lens

How even is the light?

The spread of light remains the same regardless of dimming,

The drop off of light (and colour change) is noted in this photo of the light shining on white background paper. Exposures noted are in stops, relative to the brightness at the centre.

Drop-off of light

Drop-off of light

Dimming

The product claims “Power variation: 0-100% stepless adjustment”. However my tests show that the difference between max and min power is only 3 stops. So that would be 15-100% !

Diffuser

The supplied diffuser snaps into place with magnets. It succeeds in diffusing the edges, and the drop-off is shown below:

Light drop-off with diffuser

Light drop-off with diffuser

Focus control

The focus knob physically moves the LED within the unit. When all the way in, this halves the diameter of the light beam.

Light drop-off when focussed tightly

Light drop-off when focussed tightly

[Update 09.Oct.2014] With the Fresnel

Today the replacement fresnel lenses arrived in the post.

Now the orange ring around the edge is gone, and there is a much smoother drop-off:

Light drop-off with fresnel lens fitted

Light drop-off with fresnel lens fitted

[Update 28.Jun.2015] photomart

The web-based company photomart have just started selling this light. They market it as the “Hollywood led hybrid CE-1500WS”.

It is worth noting that the model they show in their brochure and online (http://shop.photomart.co.uk/led-soft-focus-hollywood-1500ws.html) does NOT have the fresnel lens.

 

Their price is currently £396.

If anyone wants one, I can get them sent direct from the makers for £300 (you may need to pay approx £22 import duty), or £520 for 2 of them.

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LED Softbox Test

[Note: This is being published as a “work in progress”, so I will be adding photos, framegrabs and video clips over the next few days, as I have time]

I heard about a new make of LED softboxes which seem to be being used by some photographers and though it would be good to test them and see if they live up to their claims. I contacted the distributors and was sent 2 to test. In addition I asked for dimmable transformers.

I tested them with both a stills camera (the Canon 5D Mark II) and a video camera (Red Epic).

Size and Packaging

Each panel comes well protected in a thick cardboard box with foam corner protection and a foam front panel protector. The size of the packaging is 66cm x 63cm x 5.5cm._MG_3181

The panel itself is very thin (about half the width of a £1 coin) _MG_3185 and measures 595 x 595mm square _MG_3184

The only connector is a socket into which you plug the transformer. You can either use a fixed brightness transformer (supplied with the unit) or buy a dimmable transformer (as shown here) _MG_3182

Colour Temperature

The box and specs claim they are 4500K. However in testing they turned out to be closer to 4100K.

Intensity

I took a series of photos with the light at 2m, 1m and 0.5m from the subject (a black/white/grey card). The ISO was set to 800, the aperture was f/2.8.

Full-at-0,5m,-_MG_3180 At 0.5m, the shutter speed was 1/1250th.

 

Full-at-1m,-_MG_3179  At 1m, the shutter speed was 1/500th.

Full-at-2m,-_MG_3177At 2m, the shutter speed was 1/125th.

Video Flicker

coming next