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Archive 2012 · Canon Speedlite vs LED light.
  
 
jaybird555
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p.1 #1 · Canon Speedlite vs LED light.


I been photographing bees with a Canon Speedlite 580 EX ll. but you are limited to 10 flashes in succession to avoid overheating. Does anybody had any experiences with any of the LED lights.One of the advantages that I can see is you just leave it on with minimal overheating (if any), but I just wonder what the light output and the range is compared to a flash.


Edited on Feb 08, 2012 at 01:24 AM · View previous versions



Feb 07, 2012 at 10:29 PM
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p.1 #2 · Canon Speedlite vs LED light.


You need a light which has a good CRI. Most LED lights do not have this.
Right now, the LED lights at the forefront of the industry are like the type by CREE still have a pretty awful spectral response. It is not good for color photography.

Xenon flashes like the speedlights have a really good CRI across the whole visual spectrum that comes pretty close to mimicking sunlight.

I have tried to make a decent LED flash (mainly for small size and light weight in this case) but the real problem is relative intensity and the color spectrum.

You can get good intensity with enough LEDs, and driver circuitry can be bought in ready-to-go modules like the type sold by LEDdynamics.

You can use an RGB LED to get a better spectrum, but, the intensity will be limited. Compromises do exist such as LEDs that have both 'white' and RGB on the same chip, but these are just compromises that fall somewhere between the two.

http://www.cree.com/products/pdf/XLampCXA2011.pdf (series of 'white' LEDs)
1st table at the top of page four.

http://www.cree.com/products/pdf/XLampMC-E.pdf
example Red-Green-Blue-White LED

http://media.digikey.com/pdf/Data%20Sheets/Osram%20PDFs/LE_ATB_S2W.pdf
example Amber-Green-Blue LED, see the graph on page 6

I have several LED lights that are used for video lighting 'on the go' where light weight and efficiency (everything runs of battery power -- less efficient - larger battery to carry around) are important. They are unbeatable / unmatched for this application, ie. a 6000-8000 lumen video light that can be easily carried and run off a small battery for 30 minutes at max brightness. But for serious photography, I'm still sticking with speedlights.

Also the overheating thing is a myth. You can probably use it as a flash and not have to worry about it heating up. But a high power setup that's going to be on with any intensity for more than a few seconds will need cooling or it will bake, and that means less light intensity, much shorter life, and possibly burning it up on the spot. Most of the video lights I use have a relatively large heatsink and some have fans, this is an important design consideration, you can't ignore it.



Feb 08, 2012 at 12:45 AM
big country
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p.1 #3 · Canon Speedlite vs LED light.


the only LED light i am interested in at the moment is jerry ghionis's ice light.


Feb 08, 2012 at 01:29 AM
Kisutch
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p.1 #4 · Canon Speedlite vs LED light.


If this type of photography is important, you could look at a Paul buff flash for price similar to 580. Or get a flash without thermal protection, power it off DIY sla battery pack, and shoot 1/4 or less power, which you need to freeze action anyway. Maybe one of those big sun pack tato mashers.


Feb 08, 2012 at 05:52 AM
cgardner
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p.1 #5 · Canon Speedlite vs LED light.


jaybird555 wrote:
I been photographing bees with a Canon Speedlite 580 EX ll. but you are limited to 10 flashes in succession to avoid overheating. Does anybody had any experiences with any of the LED lights.One of the advantages that I can see is you just leave it on with minimal overheating (if any), but I just wonder what the light output and the range is compared to a flash.


Have you found your flash shutting down after 10 flashes or are you simply speculating / worrying that it will?

Canon added thermal protection in the form of a cut-off to the 580exII and an early adopter did a torture test of his driven with an external battery pack to discover then the thermal protection would kick in. It found that it occurred after 20 consecutive full power flashes and 70 flashes at 1/2 power. So shooting pace and distance (% capacity used) are factors.

LPA Designs, the maker of PW Flex TTL radio triggers investigating reports of HHS using it's triggers causing 580exII failures discovered the cause to be related to arcing between the flash tube contacts and the shielding rather than heat related. The spacing of the shielding wasn't consistent unit-to-unit which is why come worked fine and others failed. The 430exII which has a different shield design didn't suffer similar failures.

If you find your self in situations where you can't pace your shooting and continually hit the thermal "nanny" and it gives you a "time out" then redundant flashes or flashes / bodies would be a better solution than LEDs that don't have the same output or cost effectiveness in terms of Lux for the buck spent on the gear.




Feb 08, 2012 at 01:48 PM
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p.1 #6 · Canon Speedlite vs LED light.


cgardner he may be outdoors in the heat (he said he was photographing bees), or perhaps using the strobe feature on the flash? That's why I'd guess he's only getting 10 flashes.


Feb 08, 2012 at 06:13 PM
 

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cgardner
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p.1 #7 · Canon Speedlite vs LED light.


10 flashes is what the manuals have long said, even with the 580ex which doesn't have the thermal nanny.


Feb 08, 2012 at 07:32 PM
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p.1 #8 · Canon Speedlite vs LED light.


If you are only using a flash at very low power for gentle shadow fill light, you might be able to get away with an LED panel. However, a flash is very good at doing what it is designed for: putting out a lot of light in a very short time; LEDs are much more suitable for sustained light over longer periods of time.

Just for a rough comparison, a typical flash unit at full power might be designed to put out ~80 Watt-Seconds of light (equivalent to the light put out by an 80 Watt source for one second, but all squeezed into a 1/1000 second burst). If you wanted to use an LED panel instead, using a slow-ish 1/50s shutter speed, you would need an (80 W-s)/(1/50 s) = 4000 Watt LED array. Dragging around the diesel generator trailer to power this would be inconvenient. This comparison isn't exact, since I haven't accounted for the different efficiencies of the different light sources, but should be close enough to give you a sense of scale --- for high peak intensity, short bursts of light, other lighting technologies are nowhere near to flash tubes.



Feb 08, 2012 at 08:54 PM
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p.1 #9 · Canon Speedlite vs LED light.


mpmendenhall LEDs can already do that. Or close.
4000 watts is not much of a stretch with the modern arrays. Intensity alone isn't the problem; you can get intensity, you just can't get intensity with good color spectrum.
ie. http://search.digikey.com/us/en/products/BXRA-50C9000-J-00/976-1069-ND/2797759
That's a 15,000 lumen array that's a roughly 35mm diameter circle. Two side by side would be 30,000 lumens or roughly equivelent to 3000 watt incadescent light bulb. Actual power consumed is only around 150-200Watts per array. 32V, 10A doesn't require any kind of generator, that's not too hard to power with a small battery if all you want is flashes, or a somewhat larger (but still portable) battery if you want 30 minutes of continuous use.

I made a video back in May demonstrating a small LED strobe (around 800 lumens -- 100 watt equiv) and today I have one that will put out roughly 6000-8000 lumens. It just doesn't have the good spectrum that the flash tubes have.



Feb 08, 2012 at 10:50 PM
mpmendenhall
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p.1 #10 · Canon Speedlite vs LED light.


Access wrote:
mpmendenhall LEDs can already do that. Or close.
4000 watts is not much of a stretch with the modern arrays.


Yes, you can get pretty big LED arrays now. But when I estimated that you need ~4000W of output, I didn't mean "the equivalent of 4000W incandescent lights" (which are rather inefficient at turning energy into light), but actually more like 4000W of power consumption by the LEDs (to be comparable to the light coming from a flash/arc lamp, which has far higher efficiency than incandescent bulbs). An LED array that consumes 4kW is a whopping big array, and takes a hefty power source to run (a lot bigger than the 4 AA cells that power a camera flash). For video, where you need continuous light anyways, LEDs can be great; for pulsed light, solid state devices are still not competitive with flash tubes.



Feb 08, 2012 at 11:42 PM
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p.1 #11 · Canon Speedlite vs LED light.


Ah okay. I'll take your word for it, I've never actually measured how much a flash tube puts out; I've always just based it on how much light I need to do what I do.


Feb 09, 2012 at 01:20 AM
Kisutch
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p.1 #12 · Canon Speedlite vs LED light.


Yeah, wondering if 580 exIi actually powers off after 10 pops at low power--I have had issues at 1/2 to 1/1, but for macro I'd think you could shoot 1/16 or so, have you tested the thermal shutoff at low power?


Feb 09, 2012 at 07:24 AM





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