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LED Flash

 
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lothman



Joined: 14 Feb 2009
Posts: 376
Location: Stuttgart/Germany

PostPosted: Sun Feb 21, 2016 1:52 pm    Post subject: LED Flash Reply with quote

Hi,

has anyone tried this flash for only 42$ ?

http://www.ebay.de/itm/Double-Twin-Flashes-LED-Macro-Ring-Flash-Light-for-DSLR-Camera-New-/191797946344?hash=item2ca80c67e8:g:rzIAAOSwL7VWsXi1



Or is there another source of an (adjustable) twin Flash.

Regards
Lothman
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rjlittlefield
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Joined: 01 Aug 2006
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Location: Richland, Washington State, USA

PostPosted: Sun Feb 21, 2016 1:59 pm    Post subject: Reply with quote

You've probably noticed already, but beware the exposure time, quoted as 1/100 second.

--Rik
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lothman



Joined: 14 Feb 2009
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Location: Stuttgart/Germany

PostPosted: Mon Feb 22, 2016 7:53 am    Post subject: Reply with quote

do you expect 1/100 is too long to freeze vibrations?
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ChrisR
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PostPosted: Mon Feb 22, 2016 9:52 am    Post subject: Reply with quote

How about $26? We'd need a bulk order Smile
http://travor.en.made-in-china.com/product/FSVJNjfPwBWy/China-Magic-Elf-LED-Macro-Flash-Ml-2D-for-Canon-and-Nikon-Cameras.html

This is potentially wonderful.
GN 21 at 10ms
Lets say they overestimate the power by only 100%, and we use Eff f/21.

1m distance using 20ms
So if I put these say 5cm from the subject
I'd need a pulse (5/100 )² x 20ms = 50µs. That'll do.

Perhaps the 10ms is when turned right down - 7 stops? More?
1.28 seconds at full power?
Still usable very close...
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Lou Jost



Joined: 04 Sep 2015
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Location: Ecuador

PostPosted: Mon Feb 22, 2016 10:27 am    Post subject: Reply with quote

That seems too slow to stop vibrations unless you already have a setup that can use continuous light. And in that case you might as well use continuous light. However I guess it could still be useful in cases where the subject is sensitive to heat.
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ChrisR
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PostPosted: Sat Mar 05, 2016 12:14 pm    Post subject: Reply with quote

I have one.
The published specification, repeated in the User Guide, says:
Flash GN: 21 (no ISO is quoted)
Effective distance: 5cm - 2m
Color temperature: 5500K
Exposure time 1/100s
Power : 4 AA batteries.
Power adjustable from 1/1 to 1/64

Well it was correct about the batteries.

At iso 200, I measure about GN 5.5 (0.5 metres, f/11)
Duration I can't measure accurately yet, but a full "flash" is about 350ms.
Minimum flash is supposed to be 1/64th of a full flash, but exposures suggest it's about 1.66 stops less than a full flash, not 6.0 stops less.
I don't think the flash period changes.

The light is a little brighter in continuous mode than flash. The "power" setting again, reduces it by up to 1.66 stops.


I didn't expect it to be close to the specification, but it's worse than that.
Either mine's faulty, or it's not very useful.

For a picture at 1:1, marked aperture f/11 (Effective aperture f/22) on my MP-E65, I have to use eg 160th second at iso1600.

Can't wait to hear what anyone else has found.

Perhaps we should work on a 20Watt LED conversion - the "paddles" are fairly convenient!
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Chris R
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ChrisR
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PostPosted: Tue Apr 12, 2016 3:49 am    Post subject: Reply with quote

After about dozen ebay messages I finally got a reasonable "partial refund "from the seller.

It's moderately useful as a general purpose focus light - eg one of the paddles can go behind a subect, one can go each side if using a compact or a phone.

I've noticed the product has diappeared from Amazon, LinkDelight and one or two otherwise normally reliable sellers.
I suspect that the manufacturers' claims are simply nonsense, so the sellers have had to withdraw them. I find no comments or reviews of the item though.

Modified, it could be a lot more useful. But I have a house full of things with that epitaph.
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Last edited by ChrisR on Tue Apr 12, 2016 5:47 am; edited 1 time in total
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mjkzz



Joined: 01 Jul 2015
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PostPosted: Tue Apr 12, 2016 4:42 am    Post subject: Reply with quote

Chris, from what you observed, it seems that it is designed by a bunch of engineer who does not have a clue of macro photography.

The "ring light" I tested was designed by two LED engineers who are specialized in LED light used in household, they are novice in embedded software design, the thing was buggy, to the tune of outputting wrong level of flash, locking up in about 10 minutes of use. But they invested a lot of money to create plastic molding, securing source of components, etc. Waste of money
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ChrisR
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PostPosted: Tue Apr 12, 2016 5:46 am    Post subject: Reply with quote

Yes, If they applied some intelligence they could probably produce a useful product..

I'm thinking of adding some high power LEDs, and a big capacitor. What do you think ? Smile
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mjkzz



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PostPosted: Tue Apr 12, 2016 7:26 am    Post subject: Reply with quote

the most difficult part is to find a high powered LED with high CRI at reasonable price. You would also need some sort of reflector, like those in softbox, to help diffusing light (or maybe just add a softbox)
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lothman



Joined: 14 Feb 2009
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Location: Stuttgart/Germany

PostPosted: Tue Apr 12, 2016 9:38 am    Post subject: Reply with quote

ChrisR wrote:
After about dozen ebay messages I finally got a reasonable "partial refund "from the seller.


mine (ordered 22th February) is still not delivered, let's see what happens after another dozen ebay mails Sad

edit:
found this: https://www.youtube.com/watch?v=O1j2t0-IBvY a video from the so called Travor ML-2D flash. Chris is this the version you have?
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didin22



Joined: 25 Jan 2011
Posts: 43
Location: France

PostPosted: Tue Aug 16, 2016 11:30 am    Post subject: Reply with quote

I just received the 3 flash heads version.
I intend to use it in field for fill-in lighting and focus-stacking.

Pro :
-Operating is very easy thanks to the back panel.
-Battery life is quite good. I did hundreds of pictures without a notable power loss.
-Light power is enough for my kind of use.

Cons:
-Poor build quality. The plastic is not thick enough IMO.
-Flexible arms are not stiff enough.
-Does not work well with elecronic shutter. I use a EM5 mk II that has the focus bracketing function and an electronic shutter (a dream comes true!)
but the led based system appears to have an issue with non global electronic shutter. Sometimes things are working and sometimes no.
i recommend to read this topic for a more technical explanation of this issue: http://www.photomacrography.net/forum/viewtopic.php?t=31165&highlight=led

Some pictures done with this flash. I did not use any diffuser. The last one is a focus-stacked image.



Tettigonia viridissima by didin21, sur Flickr


Thecophora sp by didin21, sur Flickr


Dasypoda altercator by didin21, sur Flickr
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ChrisR
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PostPosted: Tue Aug 16, 2016 2:45 pm    Post subject: Reply with quote

Some super shots there. But which model is it? I can't find one with 3 heads.
What's the duration of the flash?

Lothar - I missed your question. Yes that's the one I have. It's not junk, but the manufacturer's description is!
The "flash" duration is so long that a manual On/Off would have been as good, and
the intensity range adjustment is so narrow that it's a waste of time, and
it's pretty dim.
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didin22



Joined: 25 Jan 2011
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Location: France

PostPosted: Wed Aug 17, 2016 2:45 am    Post subject: Reply with quote

Thank you Chris,
Googlise ml-3d led macro flash to find the 3 heads version.
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