Looking to build a ring light

[bstrickler]

Well, I've been getting into macro B&W photography, and I've been having some troubles with getting enough light to my camera, because I'm using 100 and lower film (as slow as 20 ASA)... I can't use the manufactured ones, because I'm usually getting 1" or closer to the subject, and most of those look like they stick out at least that much, negating their usability for me.

I've been trying to figure out if I need high CRI, or just mix warm, neutral, and cool white LED's, to get good pictures. I've been doing some research, and it's pretty confusing or frustrating.

With high CRI LED's, I'd be having to spend at least $150 to make a good ring light (10 Nichia 083 LED's, plus making a ring, a driver, finding/making a diffusor, and a battery pack). I don't have that kind of money right now, though, so that's currently out of the question, unless there's a way to get high CRI LED's for less.

I also can't just buy the manufactured ones, because with film, you can't set the white balance, and LED's don't usually give the right tones for me, and neither do incan's.

I've taken *some* pictures, using my Quark AA^2 NW to light them, and its worked fairly decently for wood, and filling in the shadows, but somethings missing.



Anyone have any input on how to go about aquiring the right LED's?


~Brian

 

[NYCaver]

I don't know where you're going to find high CRI led's for sale cheaply but Future is a source for high CRI luxeons.

For instance:
http://www.futureelectronics.com/en...d-emitters/white/Pages/8070005-LXML-PW71.aspx

I'm not sure they sell mounted LED's though.

Also check out luxeonstar.com. They will mount LED's and it looks cheaper than Future.

Mixing LED's like you mentioned could work. You basically want to illuminate as much of the visible color spectrum as possible. I've never done this before so I can't say how well it works but maybe someone else who has can shed some light on the topic.

Are you only using this for B&W photography? If so, you probably have a lot more room to work with in terms of the CCT or color temperature of the light source.

 

[bstrickler]

Are you only using this for B&W photography? If so, you probably have a lot more room to work with in terms of the CCT or color temperature of the light source.

Cheap, for me, is under $9/emitter for high CRI. Some of the ones I was looking for on CPF were $15+ per emitter. When looking to use 8-10 emitters, that adds up QUICK.

Looks like I found 5 high CRI SSC's, but idk if the person still has them or not. Hopefully they do.

Yes, I will be only using them for B&W photography. Color isn't a huge attraction to me, right now.

Thanks for the info, I'll check those links out.

~Brian

 

[snarfer]

I think you might get more bang for your buck with a DIY fiber optic setup that uses your existing flash.

Also, I don't understand why you'd be concerned with color rendering (CRI) if your application is black and white.

 

[bstrickler]

Also, I don't understand why you'd be concerned with color rendering (CRI) if your application is black and white.

The film is still sensitive to the wavelengths we see, so if the colors are too red, it will act like a red filter, and negate some of the blues, and if the LED's are too blue, it will act like a blue filter, and block out reds.

I'm not 100% sure how a "low" CRI LED will affect the film, so I want to try to keep it as close to sunlight renditioning as possible.

~Brian

 

[bstrickler]

Just an update:

I have the heatsink made. I completely forgot to take pics of what it looked like before. Here's the after pics, though:

http://i3.photobucket.com/albums/y85/Bstrickler/DSC07108.jpg
http://i3.photobucket.com/albums/y85/Bstrickler/DSC07109.jpg
http://i3.photobucket.com/albums/y85/Bstrickler/DSC07110.jpg
http://i3.photobucket.com/albums/y85/Bstrickler/DSC07111.jpg

Stuff that still needs to be done:

Buy 6 more high CRI P4's (one of the P4's is from my P60L),

Design a driver to run them (power will be controlled by a pot, if I can find the right stuff)

Put in set-screws, so the ring light doesn't accidentally fall off when in use.

Make an adapter for smaller diameter lenses

Get some optics for distant shooting (i.e. portraits... Hey, why not use the full capabilities of the P4's?)

 

[Mash]

Will your driver run on batteries or mains (studio etc)?

 

[JB01245]

http://www.diyphotography.net/diy-macro-lighting-led-ring

 

[bstrickler]

Will your driver run on batteries or mains (studio etc)?

It will run off of battery and the ability for mains (using a step-up driver) (most likely IMR, with the driver I have in mind.) I will be running 5 strings of 2 LED's for a total output of 16.25v @ 1.5 amp (each LED will be driven @ 3.25v 750mA), or 10 series, each driven at 3.5v @ 800-1000mA peak (all depends on the brightness I will really need, to get what I want), and it will be driven by 1 or 2 26500 or 18650 (depending on what total current draw will be), or a laptop power supply (assuming it will be able to handle the draw required).

Using 10 of these LED's:

http://www.mouser.com/Search/ProductDetail.aspx?qs=sGAEpiMZZMvbrKVFTEWTlqOZlvE%2f%2fZRzCkdlGTKsMqY%3d (85 CRI, I think) or
http://www.mouser.com/Search/ProductDetail.aspx?R=S42182-S1virtualkey61510000virtualkey889-S42182-S1 (93 CRI)

I still have to make the driver (along with other boards), and get the rest of the LED's (need 6 more).

All-in-all, its probably going to be quite expensive, but I'll love it.