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TLD



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Ultimate Geek
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Topic # 162223 2-Feb-2015 14:55
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I'm going to call this a work in progress because results are not what I hoped for so far, but I started the project before I had done proper research, so my bad.  I have two proprietary LED light panels that cost me $500 each from Photo & Video.  They are fantastic to work with. No heat, good WB, and you obviously need a constant light source for video.

The problem is I bought the components before realizing the difference between SMD3058 LED strips, and the much more powerful SMD5050 LED strips.  When I noticed my mistake I decided to carry on because its possible to get something like three times as many 3058 LEDs in a given area, so I hoped quantity might cancel out individual LED brightness.  That didn't happen.

This is where I was up to a few days ago and shows the nearly finished panel and outstanding materials


And this is the finished panel


The metal strip at the bottom spreads the mounting point load to the outside of the box.  I felt the box would twist and break without this.

Switch and DC power socket.  I used to do this stuff for a living, but it sure comes hard with my much older eyes.


And the proof of the pudding...  :-(   This shows the DIY using compared with one of the Photo & Video panels.  Both exactly one metre from white foam board.  WD set to daylight. Exposure measured with my Sekonic L-758DR and files completely as taken with zero adjustment.

The most noticable difference is the blue cast with the DIY unit.  The sampled RGB values show the extent of the error.  The other noticable difference is the 1.66 difference in panel brightness.  Neither light comes remotely close to my big Bowens flash units (four or five stops) but they are still useful.



I have most of what I need to make another panel but will need the 5050 LED strips (two off at $50).  I also started with a PSU that will power several panels, so I will definitely carry on.




Trevor Dennis
Rapaura (near Blenheim)

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TLD



694 posts

Ultimate Geek
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  Reply # 1227777 2-Feb-2015 14:59
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Out of interest, how are people seeing the lower half of the last image?  It looks a touch red on my monitor, but I just pasted a screen grab into Photoshop, and it samples exactly same as the original with slight weakness in the green channel.  Surprising how much difference it makes!




Trevor Dennis
Rapaura (near Blenheim)

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  Reply # 1227780 2-Feb-2015 15:12
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I have three monitors at work.  Both images look surprisingly different on all of them.  The top image is a grey\green\blue and the bottom image has a magenta tinge either all over or in zones.

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  Reply # 1227783 2-Feb-2015 15:21
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Hi - nice work on the panel - LED's are becoming a very useful lighting source for a variety of areas. To my eye the top image is a bit cyan and the bottom image is rather magenta. It'd be interesting to see how clean and consistent the light is with a custom white balance.. but that becomes problematic when you're shooting with mixed light sources....




Cheers,
Mike

Photographer/Videographer clickmedia.nz


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  Reply # 1227786 2-Feb-2015 15:28
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bottom image is a little red on the right lower half.
Your panel looks good in comparison


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  Reply # 1243274 20-Feb-2015 20:19
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They wont last if they are all stuffed into an insulating box like that without any heatsinking.

Also, how have you sorted out your power supply to put it into production from how you were testing it?

edit:

Also, feed power into every 2nd or so strip, the cheaper strips have thin copper so signifigant resistance to them making them noticibly dim out after a couple of meters.




Richard rich.ms

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