December 12, 2015 at 21:36 #26640
Our main aim is to use lights for still photography not video but these look like an interesting alternative to flash. Has anyone used them for still (or video) work and have any feedback / thoughts?December 16, 2015 at 14:09 #26665
They look OK, but I’m very wary of any LED-based lighting that comes with filters. I know Rotolight are fairly well respected, but the LEDs have very “spiky” colour spectra and filtering only makes an already bad situation worse. At least they are bi-colour so have at least got something to fill in the skin-tone orange.
These ones also seem a bit in-between as size goes to me, too. 15 cm across is not big enough to produce a really good soft light without some sort of soft box or diffusion, but nor is it small enough to make nice sharp shadows like a Fresnel would. I think you’d probably lose a lot of oomph by the time you’ve put them through a softbox.
I don’t think LED lighting has really matured yet- I don’t think they are really a substitute for flash for stills work for the moment. When the “proper” six colour sort start filtering their way down from Arri premium prices to more reasonable alternatives I think it’ll be worth a look, though!
Cheers, HywelDecember 16, 2015 at 15:00 #26669
Oooh! Just discovered a fabulous resource for LED lighting:
Downloading the result for the Rotolight Neo at 5600 K (daylight white balance) we get:
and for 3200 K (Tungsten) we get:
Background on these tests for the ultra-techie:
What are we looking at in these diagrams? First the colour swatches. There is an inner square and an outer square. The outer square is a reference light (either daylight on an actual tungsten light). The inner square in how that colour swatch looks when illustrated by the light being tested. In the ideal case there will be no difference.
The Rotolights are doing pretty well, actually. The most critical patches for us are the first two, which represent dark and pale skin tones. The differences are very minor. For 5600K we can see that the lights struggle with teal, which is always a weak spot of LED, and dark blue. They greys are nicely neutral.
At 3200K again the all important skin tones look good. Teal, blues, pink and purple look a bit off, but nothing to write home about. All in all that’s a very creditable performance. I’m impressed, LED lighting has come a long way in the last few years.
If you want a “colour quality” single number for a light, it is the TLCI-2012 number: 90 and 91 (out of a hundred). This is not to be confused with the CRI, which manufacturers are still quoting but which really doesn’t have much applicability to discontinuous spectrum lights like LED.
If you look at the curves you’ll be able to understand immediately what is causing these issues. The curve is a power spectrum of the light as a function of wavelength, from violet on the left hand side to deep red on the right hand side. The light blue curve is the reference illuminant (daylight for 5600K and tungsten for 3200K). The black curve is what the light is putting out.
You can see what I mean about LED lighting having a spiky spectrum. There’s a big peak in the blue, a gap in the teal, then a more modest broad peak in the green through to a second peak in the orange.
You can immediately see that light is lacking in the violet (there’s nothing in the black curve above 420 nm) and the deep red (below about 680 nm the black curve falls a long way short of the reference line).
That’s why teal, pink and violet cause problems and why deep red can also be a problem. But for most colours it looks like those lights are pretty decent.
There is one other factor that can cause trouble- the way the peaks in the LED spectrum can interact with the colours in the filter of your camera. There’s no real way of knowing that without trying a given light with your camera before you buy. Problems most commonly appear as magenta and green shifts which vary across the image, so you might find your reds have a very magenta tinge and but your skin tones have a green cast.
But nonetheless I’m impressed to see colour rendition this good from relatively cheap LED panels, very encouraging, and I think one should be able to get pretty good results with them. The size / power / softness issue would still cause me some concern, though.
Cheers, HywelFebruary 2, 2016 at 14:39 #26761
Thank you, Hywel, for the careful thoughts. It is very kind of you and generous of time when I know you are busy.
In January, my wife and I went to a photography show in London. Let us just say – as she keeps reminding me – that the Rotolight Neos she bought were nothing like as expensive as what I bought. Here are some first examples of the results, taken at TopHat Studio in Newark and starring a stunning blonde Temptress Kate.
In my first shot, the Rotolights provide the main lighting
We were told it was difficult to light this “1970s themed” set because studio flash tended to drown the featured table lamps so we thought it a good chance to try the Rotolights. There are two used, just in front of her to camera right and behind her to camera left. The round lights create a satisfying round catch-light in Kate’s eye.
To emphasise the 70s colours, the colour temperature has also been tinkered with. The lights – and camera – were set at 4300K but the temperature upped to about 6000 during editing. I’m told this further emphasises the 70s feel. Those who can see colours will no doubt form their own opinions.
In the remaining two shots, the Rotolights supplement daylight.
In this “bathroom” set, there is a window to camera left and the set also gets significant light from one of the studio’s flourescent house lights above and to the right. The Rotolight is providing fill to Kate’s face and inside the bath.
Here, the window is to camera right and the Rotolight is providing the light from the left.
In all these shots, ISO had to be turned up a bit – to 800 for the 70s room.
I offer these shots for members’ information. My personal view so far is that LED lights have their uses but are not a substitute for good flash you want strong light.
We are now feeling encouraged into video where we can make use of the special effects on the Rotolight, such as lightning, fire, tv and flashing police blue lights. 🙂
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