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Author Topic: LED/Fresnel Lighting recommendation wanted  (Read 2742 times)
Jim Kasson
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« on: December 31, 2013, 10:51:42 AM »
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Working on testing cameras and lenses, I find myself in need of a continuous illumination source with variable spread and the ability to vary the intensity without changing the spectrum appreciably.

I'm looking at the Litepanels Sola 6 and the Fotodiox DY-200. The Litepanels unit is much more expensive and seems to produce less light when turned up all the way. Knowing that you rarely get something for nothing, I wonder what I'm giving up with the Fotodiox unit. Reliability? Service life? Smoothness of spectrum? Dimmability? Something I haven't thought of but should have?

I would like very much to get at least an 8-stop range of light output.

Is there another alternative that I should be considering?

Any advice and/or suggestions are appreciated.

Jim
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Sareesh Sudhakaran
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« Reply #1 on: January 01, 2014, 09:33:48 AM »
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Working on testing cameras and lenses, I find myself in need of a continuous illumination source with variable spread and the ability to vary the intensity without changing the spectrum appreciably.

I'm looking at the Litepanels Sola 6 and the Fotodiox DY-200. The Litepanels unit is much more expensive and seems to produce less light when turned up all the way. Knowing that you rarely get something for nothing, I wonder what I'm giving up with the Fotodiox unit. Reliability? Service life? Smoothness of spectrum? Dimmability? Something I haven't thought of but should have?

I would like very much to get at least an 8-stop range of light output.

Is there another alternative that I should be considering?

Any advice and/or suggestions are appreciated.

Jim

The only LED fresnel that I know of that can stand up to traditional lights is the Arri L7 series, and it is not practical to use on location due to its size and weight (studio is okay). Two alternatives I haven't tested are the Mole Richardson and the Zylight F8.

I've used the Litepanels but have never seen the Fotodiox. Isn't the output too low for photography work? The Arri is 200 Watts and still isn't good enough to beat a 650 Watt tungsten fresnel.
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Jim Kasson
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« Reply #2 on: January 01, 2014, 10:45:24 AM »
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The only LED fresnel that I know of that can stand up to traditional lights is the Arri L7 series, and it is not practical to use on location due to its size and weight (studio is okay). Two alternatives I haven't tested are the Mole Richardson and the Zylight F8.

I've used the Litepanels but have never seen the Fotodiox. Isn't the output too low for photography work? The Arri is 200 Watts and still isn't good enough to beat a 650 Watt tungsten Fresnel.

Thanks, Sareesh. I checked out the two alternatives you mentioned. The Mole-Richardson JuniorLED 200W 8" Fresnel (Daylight) has the same power draw as the Fotodiox, and costs about half again as much. It's got a CRI of 90, which is a lot better than the Fotodiox's 85. The Zylight F8 LED Fresnel (Daylight) has the same 100W draw as the Litepanels Sola 6, costs about the same, and has an eight-inch lens as opposed to the Sola's six-inch one. I'm still trying to figure out why the Litepanels and Zylight units are at least three times as expensive per watt as the other two.

The Mole-Richardson 200w unit has a little over a 3-stop dimming range, which lets it out for my use. The others all say they dim to 0, but something has to go wrong as the light gets very dim.

The Arri L7C is about 14 lbs in active cooling configuration, but, you're right, the passive cooled version is a monster. The CRI is nice, though. Litepanels doesn't quote a CRI that I've found.

I know that input power is not the way to rate LED lights, and that efficiency varies with the design of the blue pumping LED and of the emitting phosphors. I'm suspicious of manufacturer's light output claims unless supported by an ISO or CIE test method, and those appear to be thin on the ground. Perhaps SMPTE has done something here?

One thing that you say gives me pause. I am used to applying about a 5x multiplier to the wattage of a high-efficiency Cree LED with a CRI of 93 to get the tungsten equivalent, maybe a little higher for 5000 Kelvin sources and a little lower for 2700 Kelvin ones. When you say that a 200w Arri isn't better than a 650w tungsten, that makes me think there's something going on that I don't understand. I would think that a 200w LED would match a kilowatt tungsten. Zylight says their 100w unit is the equivalent of a 650w tungsten lamp. Hmm...

Thanks,

Jim
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bcooter
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« Reply #3 on: January 02, 2014, 08:02:04 AM »
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 I'm suspicious of manufacturer's light output claims unless supported by an ISO or CIE test method, and those appear to be thin on the ground.

You didn't mention your use, still, motion, studio, locaiton, high powered keys, lowered fill, etc. etc., so it's difficult to recommend.

We use Lightpanels 1x1's and the smaller sizes and just recently purchased an Ikan set.

The lightpanels are fairly robust (though the Dc convertor connection is somewhat loose).

The ONLY reason I use led's is the power draw and speed.    The 1x1's are all rigged to hold V mounts and of course they all run 240 to 110 if your on mains.

This was shot with one small led hand lightpanel held and a reflector



I do like the Ikans, can't be sure of the reliability as they are new to us, but have traveled once and gone on location once without issue.

LED is a strange animal.  It casts easily with digital, especially the variable daylight and they are somewhat specular.  They produce more light than you would think but it's kind of a hard light, even with the soft versions.  I would suggest cutting some spun sheets (1/2 stop at the most) to smooth them out.  

They also make brackets where you can mount 4 1x1's into a larger fixture, though Ikan also makes some larger lights about the size of the medium kino flows, but once again they need some light spun to make work well.

This was also shot with lightpanel leds, for Key and accents  and one broncolor HMI very lightly  bounced for fill, with the leds turned warmed so the windowlight would go blue.



this is an unretouched still (actually a screen shot from a daily)  from the red 1 shot with two lightpanel led's hand held and the practicals in the background.



For HMI's I use the blue broncolors 575 to 800 watts and have about 7, could use about 10.

We only use HMI's to mix light for daylight and I don't believe the blue HMI's really produce the best look for digital, though they have medium power draw for mains and small generators.

The only issue with broncolor hmi's is they are fragile and have a few quirks, so you have to pack them securely.  

They are somewhat difficult to find and Broncolor has very little information on them, though they pack easy and are about the size of a standard flash and pack.   The produce enough light for digital though

Given my preference and working in a blacked out studio, I would work tungsten only. We have two huge tungsten kits and rarely do they go out the door anymore, as they draw a lot of power, don't mix with daylight and are heavy which requires at the least C stands, the most large rollers.

Tungsten and digital to me are made for each other, as the look is deep and makes a thicker file, even though the blue channel takes a hit.



Don't discount what you can do with what you have.

This gig came in from a designer and had a tight deadline.  All we had with us was one large set of photogenic monoblocks (I have about 30 of those things) and a bunch of grids.

I tried to get the mix with flash, eventually would have but the room was a trillion degrees so I shot it with the modeling lights and an old Aptus 22 on a contax.

It worked fine and actually the color is prettier than the black and white they asked for.



Maybe it's me, but light is light and the only rule is you can make a large light big, but it's damn hard to make a small light large.

In regards to the Arri's I tested them, they make a pretty light but don't have a lot of power for the costs.

But they're Arri's so they'll probably last a million years.

You mentioned you need 8 stops (that's a lot) but if you really need to go that low, cut a bunch of nd's and some slight spun,  that will get you where you want and since led's don't get that hot you don't have to worry about burning through a gel.\

But my final suggestion is if you think you need 4 lights you need 8, 8 12, 12 well you get the idea.

You may only use one, but it takes crafted light to make a beautiful photography even if it's daylight and you wait for the right moment, or the lighting is beyond your control you can find the right spot.



IMO

BC

« Last Edit: January 02, 2014, 08:20:46 AM by bcooter » Logged

Sareesh Sudhakaran
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« Reply #4 on: January 04, 2014, 12:17:18 AM »
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Thanks, Sareesh. I checked out the two alternatives you mentioned. The Mole-Richardson JuniorLED 200W 8" Fresnel (Daylight) has the same power draw as the Fotodiox, and costs about half again as much. It's got a CRI of 90, which is a lot better than the Fotodiox's 85. The Zylight F8 LED Fresnel (Daylight) has the same 100W draw as the Litepanels Sola 6, costs about the same, and has an eight-inch lens as opposed to the Sola's six-inch one. I'm still trying to figure out why the Litepanels and Zylight units are at least three times as expensive per watt as the other two.

I wouldn't use the CRI rating because there isn't one universal way to measure it. Litepanels had a head start, and their 1x1s are rugged enough for international travel and documentary work. I believe they deserve their billing. Zylight? I don't know. $2K seems to be going rate for an LED fresnel. Here's a comparison of specs: http://wolfcrow.com/blog/a-comparison-of-9-led-fresnel-lights/

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The Mole-Richardson 200w unit has a little over a 3-stop dimming range, which lets it out for my use. The others all say they dim to 0, but something has to go wrong as the light gets very dim.

The Arri L7C is about 14 lbs in active cooling configuration, but, you're right, the passive cooled version is a monster.

The active cooling fixture is fine. You can't hear the fan, and even four of them is barely above a whisper (sound doesn't add linearly). However, the entire philosophy of the L7 line is upgradeability, and a fan is a constant source of worry in the long term.

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Perhaps SMPTE has done something here?

Don't let me get started on the SMPTE! However, no committee can agree on measuring light and color. And, a genius like BC can make mockery of any specification!

Quote
One thing that you say gives me pause. I am used to applying about a 5x multiplier to the wattage of a high-efficiency Cree LED with a CRI of 93 to get the tungsten equivalent, maybe a little higher for 5000 Kelvin sources and a little lower for 2700 Kelvin ones. When you say that a 200w Arri isn't better than a 650w tungsten, that makes me think there's something going on that I don't understand. I would think that a 200w LED would match a kilowatt tungsten. Zylight says their 100w unit is the equivalent of a 650w tungsten lamp. Hmm...

The truth is, a 200 W LED fresnel does not match a 650 W fresnel - both Arri. You could compare the lux maps provided by Arri, but you'll notice the tungsten has a greater 'zone' of usability. E.g., at 10m flood, the L7 delivers 60 lux, while the 650W delivers 100+ Lux. The beam angles are different, too. Finally, nothing beats the color from a tungsten. All said and done, it would be better to think of the L7 as a totally different tool, and not as a replacement to a 650 W tungsten or a 200 W HMI.

About 1x1 Litepanels, I think of the quality of light as needle-like. If you're looking at 1x1s, also take a look at Photon Beard's fluorescent 1x1s - beautiful light but less rugged body, cheaper price but... fluorescent tubes. The cool thing about 1x1s is that you can bank them for a larger source on just one circuit.

If you really want punch, low wattage and a fresnel, an Arri 200 W HMI is great. But it's almost $4K.
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andrew00
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« Reply #5 on: January 04, 2014, 08:58:15 AM »
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I really like LED's as they're light, don't draw much power, aren't hot so won't fry your subject and can be dimmed easily.

That being said they do have issues - either the cheap ones tend to have colour issues, esp green/magenta (bad for skin) or the top quality ones are really expensive. I also have issue with the light output which isn't a whole lot for what you pay for.

Personally unless you can afford the cost with ease I'd stick with traditional Arri/HMI/Kino's as they're so much cheaper and 'proven'. Not to say LED's can't be excellent, just that for me it's a lot of cash for the same output of a cheapo Arri or Kino.
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