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chris_4622
28-Nov-2017, 06:18
Hi,
I'm going to build one or two of these light panels: https://www.youtube.com/watch?v=jLia59KfkSw

In shopping for LED's I've seen prices go from under $15 (ebay) for a roll (5 meters/300 LEDs) to $155 (baersupply.com). I've tried to compare apples with apples, that is 3 watts per foot tape vs. 3 watt...from different manufacturers but not every site lists the same specs. Some can be cut every 1" others at 2" or 3". As I mentioned all are for 5 meter rolls.

How can I decide which are quality and which are junk? Is price alone the determining factor?
What color temperature for B&W film? If it matters. I do plan to use these for video as well so I'm thinking 5000k.

A few years ago I bought a roll from Baer Supply, where I buy hardware for kitchen cabinets I make. After installing the tape under the cabinets I was very impressed with the result. That roll of tape was $85 which was charged to the job, but since I need at least 3 rolls, cost is a factor.

My head is spinning, any advice...

chris_4622
30-Nov-2017, 07:04
In the interest of sharing what I've learned I'll pass this along.

I bought Flexfire's Industrial Series light tape 4200K. It's a company that publishes specs including picking from the same bin for color consistency. After reading reviews about some of the cheaper options out there I decided I'm not going through the expense and work to have some failures of LED's. Fortunately I bought everything during their cyber week sale which essentially gave me the drivers for free.

The requirement for these ultra bright LED's is the use of a heat sink. I found one, 5.5" x 11.8" that will hold one roll 9'10" of lights. I'll make two of these to fit on the two light stands I already have. I expect to have enough light to bring my exposure times down to 1/15 or faster with my aperture and film choice.

Tin Can
30-Nov-2017, 07:39
Great, let's see more, when you have more!

I bought 2-900 Led 5000K Video lights maybe 5 years ago, $500 each. Still work fine.

I also bought a bi-color 600 Led panel which is 50/50 2800K and 5600K. I really dislike that one, as I never use 2800K then only get light from the 300 5000K bulbs.

I recently bought 18 48" LED 6500K shop lights. These weigh nothing. I am using 12, one failed, I have 5 spares left. Failure was flickering on and off, not temperature related. There are made of ribbon LED inside a diffuser.

https://www.amazon.com/gp/product/B01HBT3BVM/ref=oh_aui_detailpage_o07_s01?ie=UTF8&psc=1

You can see them on my Paint an Elwood thread. http://www.largeformatphotography.info/forum/showthread.php?142998-Painting-an-Elwood&p=1418076&viewfull=1#post1418076

Bob Salomon
30-Nov-2017, 08:57
In the interest of sharing what I've learned I'll pass this along.

I bought Flexfire's Industrial Series light tape 4200K. It's a company that publishes specs including picking from the same bin for color consistency. After reading reviews about some of the cheaper options out there I decided I'm not going through the expense and work to have some failures of LED's. Fortunately I bought everything during their cyber week sale which essentially gave me the drivers for free.

The requirement for these ultra bright LED's is the use of a heat sink. I found one, 5.5" x 11.8" that will hold one roll 9'10" of lights. I'll make two of these to fit on the two light stands I already have. I expect to have enough light to bring my exposure times down to 1/15 or faster with my aperture and film choice.
What is the CRI of these LEDs? Do you need to use a special paint or reflective surface or special acrylic to get the CRI into the photo range of 90 or higher? For best color the CRI of the system should be 95 or above.

HMG
30-Nov-2017, 10:19
Great, let's see more, when you have more!

I bought 2-900 Led 5000K Video lights maybe 5 years ago, $500 each. Still work fine.

I also bought a bi-color 600 Led panel which is 50/50 2800K and 5600K. I really dislike that one, as I never use 2800K then only get light from the 300 5000K bulbs.

I recently bought 18 48" LED 6500K shop lights. These weigh nothing. I am using 12, one failed, I have 5 spares left. Failure was flickering on and off, not temperature related. There are made of ribbon LED inside a diffuser.

https://www.amazon.com/gp/product/B01HBT3BVM/ref=oh_aui_detailpage_o07_s01?ie=UTF8&psc=1

You can see them on my Paint an Elwood thread. http://www.largeformatphotography.info/forum/showthread.php?142998-Painting-an-Elwood&p=1418076&viewfull=1#post1418076

Was the failure immediate (or almost immediate) or after some period of usage?

Peter De Smidt
30-Nov-2017, 10:51
https://www.provideocoalition.com/doestlcireallywork/

Tin Can
30-Nov-2017, 11:38
Was the failure immediate (or almost immediate) or after some period of usage?

Failed after 3 weeks of 4 hours a day usage. Just started flashing on and off.

I hope they work, they use 20 watts per and the light is pleasant for me.

chris_4622
1-Dec-2017, 04:35
What is the CRI of these LEDs? Do you need to use a special paint or reflective surface or special acrylic to get the CRI into the photo range of 90 or higher? For best color the CRI of the system should be 95 or above.
I bought the 42K. I'm not concerned about the CRI for B&W film and for video there are options for managing color.

The CRI reminds me of Wine Spectator's ranking numbers, the mind thinks the higher the number the better. But what if you just don't like that wine...I know color is not wine but what I'm saying is there are other things to consider than just a high CRI.

AFSmithphoto
6-Dec-2017, 05:55
I bought the 42K. I'm not concerned about the CRI for B&W film and for video there are options for managing color.

The CRI reminds me of Wine Spectator's ranking numbers, the mind thinks the higher the number the better. But what if you just don't like that wine...I know color is not wine but what I'm saying is there are other things to consider than just a high CRI.


It sounds like you may a victim of some bad info. CRI is not a measurement of color, its a measurement of how faithfully the full spectrum of color can be represented. It matters for black and white.

If a specific frequency is underrepresented by your light, anybobjects in your frame that have a color correpsonding with the frequency will appear unnaturally dark in the final picture.

Peter De Smidt
6-Dec-2017, 07:11
It sounds like you may a victim of some bad info. CRI is not a measurement of color, its a measurement of how faithfully the full spectrum of color can be represented. It matters for black and white.

If a specific frequency is underrepresented by your light, anybobjects in your frame that have a color correpsonding with the frequency will appear unnaturally dark in the final picture.

Unfortunately, CRI isn't all that good of a light quality measure. See: http://leapfroglighting.com/attention-cri-youre-no-longer-relevant/

vinny
6-Dec-2017, 09:32
Lite ribbon by LiteGear has what you need. Yes, it costs more but their stuff has a cri of 95 and is pretty damn bright. I've been using it for several years at work.

AFSmithphoto
6-Dec-2017, 10:44
Unfortunately, CRI isn't all that good of a light quality measure. See: http://leapfroglighting.com/attention-cri-youre-no-longer-relevant/


While I agree 100% that there are superior metrics to CRI, if the OP limits their LED tape search to brands they can find CQS or RA2012 data for, their options will be pretty limited.

If on the other hand you accept that above 90 cri will be "pretty good" 80-90 will be eh and below 80 not so good you at least have a starting point.

If you're needs are more specific, CRI won't get you there, but in the absence of better information, its at least worth considering as an indicator.

chris_4622
7-Dec-2017, 04:47
Lite ribbon by LiteGear has what you need. Yes, it costs more but their stuff has a cri of 95 and is pretty damn bright. I've been using it for several years at work.

Thanks vinny.

Daniel Moore
5-Jan-2018, 11:43
Interesting read and LED database for those considering a similar project:

http://indiecinemaacademy.com/complete-led-color-database-cri-tlci-cqs-tm30-15/

They consider several other factors than CRI as well.
They also mention that their database is in the process of being updated with even newer products.

scheinfluger_77
5-Jan-2018, 12:22
I have one of these and 6 six-foot versions in my garage for... garage light. Don’t know if this would work for you but they are cheap, run cool, and provide LOTS of light.

https://www.samsclub.com/sams/linkable-shop-light-honeywell-led/prod20590154.ip?athcpid=prod20590154&athena=true&athpgid=pdp&athmtid=VaV&athznid=sams_ip_VaV&parentpid=prod21062241&xid=pdp:carousel:people-who-viewed-this-item-also-viewed:3

chris_4622
7-Jan-2018, 08:53
I finished my two panels measuring 5.5" x 11.75". I can attach them together to make an almost square panel or I can mount them one above the other or use them separately. I found some 60 grids that are the right size and I also made a couple of snoots out of mat board. Everything works well.

I made some comparison exposures. Using these and then with a 500W Tungsten source. Exposures were the same, developed them together and I just made some prints. The subjects were book ends and album cover ends with plenty of various colors. I just took the prints out of the wash and the differences are so slight it's not a concern. The reds rendered slightly darker. This test was done using Ilford Fp4+ developed in tubes using Pyrocat HD 2:2:100.

Had I not already bought the Flexfire LED's I would have considered the ones Vinny mentioned because in color there is a difference, the yellows tend to render a bit green but since I made these for B&W work I'm quite happy with the results. I found a battery pack that can run both lights at the same time. I'll be testing them with a model who I've photographed before using strobes.

I hope this is useful to the community.

jim10219
28-Nov-2018, 11:48
If you're worried about CRI, then you could build a box with red, green, and blue LED's, put each color on it's own circuit with an inline potentiometer, and then you can vary the color mix as you see fit. Then just take something that you want to call white, shine the light on it, and adjust until the object looks white to you. That would also allow you to match the colors of other light sources, such as overhead lighting, daylight, or flashes. And it could act like a variable color filter for your lens for B&W work.

Bob Salomon
28-Nov-2018, 12:40
If you're worried about CRI, then you could build a box with red, green, and blue LED's, put each color on it's own circuit with an inline potentiometer, and then you can vary the color mix as you see fit. Then just take something that you want to call white, shine the light on it, and adjust until the object looks white to you. That would also allow you to match the colors of other light sources, such as overhead lighting, daylight, or flashes. And it could act like a variable color filter for your lens for B&W work.

Or find the old Kodak test patch that showed if your CRI is photo quality visually!

Bruce Watson
28-Nov-2018, 13:25
Yuji (https://www.yujiintl.com/high-cri-led-lighting) has an excellent rep. in indy video circles. They have a decent selection of DIY stuff (https://store.yujiintl.com/collections/high-cri-led-strips-ribbon) too. If it'll work for video, it'll work for anything we do here.

Pere Casals
28-Nov-2018, 14:01
Peter, there are several CRI standards, CRI R96a standard is pretty good.

Peter De Smidt
28-Nov-2018, 16:11
https://www.bhphotovideo.com/c/product/1402519-REG/dracast_dr728rgbw_728_led_rgb_white.html