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05-11-2017, 12:48 PM   #1
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LED ringflash

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Has anyone had any experience with an LED ring flash. I'm thinking of getting one for macro as they seem considerably cheaper than a conventional ring flash.
Thanks

05-11-2017, 01:13 PM   #2
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yep the yongnuo yn14ex ring flash works with the k1 and 100 2.8. it's effective.
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05-11-2017, 01:44 PM   #3
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In the "flash" mode vs continuous lighting they are slower than traditional Xenon flashes. You probably have to shoot a slower shutter speed than 1/180-200 to get it to sync. The flash duration is longer too so you may not get a stroboscopic effect to help freeze motion. Guide numbers are typically lower so you may need wider apertures or higher ISO.
05-11-2017, 02:32 PM   #4
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^^ My experience too. I'm still not aware of any LED light sources at all that have as short a duration as Xenon

05-11-2017, 04:23 PM   #5
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Certainly with some of the cheaper ones, the use of the word 'flash' is a misnomer - they only emit constant light, and in my (limited) experience of using one, they are only really suitable for static subjects. I was lucky enough to obtain a second-hand ring flash for £25 - although it is intended for Canon use, it works fine on my K20D, but obviously without any kind of TTL. It does not, however, take re-chargeable AA batteries.

Last edited by 35mmfilmfan; 05-11-2017 at 04:24 PM. Reason: Further info
05-11-2017, 08:14 PM   #6
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I recently got a Bolt VM-160 LED Macro Ring Light. I don't do a lot of macro, but I won an old Sigma Macro 50 2.8 in an auction and the light was on a B&H Deal Zone for a great price, so I got one. I has a constant light, which I like, and it also flashes. I really can't compare it to anything else, but it works for me. It is a fully manual flash.
05-12-2017, 10:26 AM   #7
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Thanks for the info everyone
05-12-2017, 09:23 PM   #8
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The “problem” is not how fast the LEDs can flash, but how much light they can output.

I just tested half a dozen LEDs of various colors: red, yellow, blue, green, and white in my collection.

I used a signal generator to pulse the LEDs ON/OFF with a square wave at rates up to a MHz and the same light detector I use for making flash duration measurements.

The combination of LEDs and the detector showed turn-ON and turn-OFF times of one or two microseconds (millionths of a second)!

I suspect the real limit of my setup is the time constant of the light detector, which appears to be around a microsecond or so. So, the LEDs may be even faster.

At any rate - one or two microseconds is WAY FASTER than any conventional standard (gas discharge tube) flash that I have measured (AF540FGZ, other Pentax, Vivitar, and Neewer flashes, as well as the built-in flash on my K3). The fastest of these, at their lowest power settings, have output light pulses of 10-20 microseconds or longer.

So, an LED ring “flash” could theoretically be very fast (depending on the actual design). However, the instantaneous light output of the several LEDs in the flash is not all that much. Hence, to get enough light for a reasonable exposure, I’d guess that the LEDs are, at best, flashed for a much longer time than the intrinsic microsecond that the LEDs are capable of.

If you are after moving objects with a ring flash, you may need a real flash. If it is just the uniform lighting you are after, I see no reason not to use the cheaper LED version.

05-13-2017, 05:39 AM   #9
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Yes it is uniform lighting for close up work so I will try a cheaper LED
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