LED portable light

[Carlos E. Martinez]

There's a very interesting thread here on a LED based portable light:

http://www.dvxuser.com/cgi-bin/DVX/YaBB.cgi?board=Links;action=display;num=1071261354

There are probably some pro products around using that formula, but the possiblities of ths specific project are really great.

Have a look and come back here comment about it.



Carlos

[Mike Cavanaugh]

I've been playing around with the same concept for a while now (Just never seem to get enought time to re-do prototypes) I first thought of it when kayaking at night - one of my friends has a headlamp with 3, super bright LED. Ran for hours on just 1 little battery.

Biggest problem seems to be the "coldness" of the LED light - been playing with filters and/or adding warm color LEDs to the array.

Another problem is obviously size - in order to get enough LEDs in one spot to make the light effective, it takes some tricky wiring.

Thanks for letting us know that there are others working on this idea!

[Don Berube]

I seem to recall that Panasonic showed a very similar LED on-camera video light for use with the DVX at the DV Expo West.

Anyone recall seeing that at the show?

- don

[Mike Rehmus]

There are some pro lights available but you'd better have a very thick wallet. These are of the size of kinoflos if I remember correctly.

I looked at them, checked the price on white LEDs ($5 in small quantities), looked at the very blue light and decided I'd wait a while.

What I would like is a ring light where I can switch off some of the LEDs depending on the shot I need.

Does anyone know if LED light is effected by camera polarizers without having to place a polarizing filter over them?

[Charles Papert]

<<What I would like is a ring light where I can switch off some of the LEDs depending on the shot I need.
>>

Here's that.

At some point this sort of thing will filter down into the prosumer market or whatever it's called now. Still quite exotic and expensive.

[Carlos E. Martinez]

<<<-- Originally posted by Mike Rehmus : There are some pro lights available but you'd better have a very thick wallet. These are of the size of kinoflos if I remember correctly.-->>>

On the URL I mentioned there's the basis for a simpler and cheaper portable light. How large you can get with it will depend on how much you will want to work.

<<<-- I looked at them, checked the price on white LEDs ($5 in small quantities), looked at the very blue light and decided I'd wait a while. -->>>

Very blue compared to what? If you are talking about Jared's photos, the light on the background should be house incandescents, which are very yellow.

About the price you should compare light output to a photo type light of similar strength. LED's advantage is they are more sturdy, cooler running and drain less.

<<<--What I would like is a ring light where I can switch off some of the LEDs depending on the shot I need.-->>>

Doing a ring light won't be easy, as you should have to cut a ring pcb. But you can assemble square LED blocks and use separate switches on each.

<<<--Does anyone know if LED light is effected by camera polarizers without having to place a polarizing filter over them?
-->>>

Why would you use a polarizer for? Are you talking about pola screens?


Carlos

[Mike Rehmus]

<<<-- Originally posted by Carlos E. Martinez : <<<-- Originally posted by Mike Rehmus : There are some pro lights available but you'd better have a very thick wallet. These are of the size of kinoflos if I remember correctly.-->>>

On the URL I mentioned there's the basis for a simpler and cheaper portable light. How large you can get with it will depend on how much you will want to work.

<<<-- I looked at them, checked the price on white LEDs ($5 in small quantities), looked at the very blue light and decided I'd wait a while. -->>>

Very blue compared to what? If you are talking about Jared's photos, the light on the background should be house incandescents, which are very yellow.

Personal experience is that the light is very blue. I have one in a flashlight.

About the price you should compare light output to a photo type light of similar strength. LED's advantage is they are more sturdy, cooler running and drain less.

Ah, but I have the other stuff now. I don't know how they compare to a HMI light either. Some things to check.

<<<--What I would like is a ring light where I can switch off some of the LEDs depending on the shot I need.-->>>

Doing a ring light won't be easy, as you should have to cut a ring pcb. But you can assemble square LED blocks and use separate switches on each.

Here around Silicon Valley, circuit boards are no problem. But a pcb isn't necessary. A thick milk plastic ring could be use with the LEDs lightly pressed into holes around the back surface. Another plastic ring could be mounted over the back of that to carry the switches and hide the point-to-point wiring. Actually, switches are probably not the correct way to do it. With the low power consumption, a better way may be to simply use a mechanical cover over the sections I want dark.

<<<--Does anyone know if LED light is effected by camera polarizers without having to place a polarizing filter over them?
-->>>

Why would you use a polarizer for? Are you talking about pola screens?

I am interested in controlling the glare that is always a possiblity with a ring light.


Carlos -->>>

[Carlos E. Martinez]

<<<-- Originally posted by Mike Rehmus :
Personal experience is that the light is very blue. I have one in a flashlight.-->>>

Perhaps you should find out first what type that one is and see which MCD family it comes from. Right now I am trying to find spectrum graphs of different film/video lamps and see which LED type may fit better where.

<<<--Ah, but I have the other stuff now. I don't know how they compare to a HMI light either. Some things to check.-->>>

What other stuff is that? What should compare to HMI?

<<<--Here around Silicon Valley, circuit boards are no problem. But a pcb isn't necessary. A thick milk plastic ring could be use with the LEDs lightly pressed into holes around the back surface. Another plastic ring could be mounted over the back of that to carry the switches and hide the point-to-point wiring. -->>>

Maybe they are no problem there, but they will probably be pricey. A pcb would also provide a secure base to work from.

I am not familiar with that plastic ring you describe.

Point to point wiring is definitely not advised on this project, in my opinion, as we are talking several LEDs to be soldered.

<<<-- Actually, switches are probably not the correct way to do it. With the low power consumption, a better way may be to simply use a mechanical cover over the sections I want dark.-->>>

A cover sounds fine to me. But a switch might be more practical. In fact we could use both.

<<<-- I am interested in controlling the glare that is always a possiblity with a ring light.-->>>

There might be some lateral glare, but the LEDs are quite directional at about 20 degrees.


Carlos

[Mike Rehmus]

<<<-- Originally posted by Carlos E. Martinez : <<<-- Originally posted by Mike Rehmus :
Personal experience is that the light is very blue. I have one in a flashlight.-->>>

Perhaps you should find out first what type that one is and see which MCD family it comes from. Right now I am trying to find spectrum graphs of different film/video lamps and see which LED type may fit better where.

<<<--Ah, but I have the other stuff now. I don't know how they compare to a HMI light either. Some things to check.-->>>

What other stuff is that? What should compare to HMI?

Sorry, I didn't write that correctly. I don't know how white LEDs compare to a HMI light. I haven't got a good enough reason to search out the details and too busy to do it during work hours.

<<<--Here around Silicon Valley, circuit boards are no problem. But a pcb isn't necessary. A thick milk plastic ring could be use with the LEDs lightly pressed into holes around the back surface. Another plastic ring could be mounted over the back of that to carry the switches and hide the point-to-point wiring. -->>>

Maybe they are no problem there, but they will probably be pricey. A pcb would also provide a secure base to work from.

PCBs are not pricey if one is willing to make one. If one wanted 10 copies, there are free design programs to lay it out and the boards are not too expensive to have made. But a quick trip to the electronics store will get me all the tools to make my own if I want to do that.

I am not familiar with that plastic ring you describe.

I would machine that myself.

Point to point wiring is definitely not advised on this project, in my opinion, as we are talking several LEDs to be soldered.

Point-to-point wiring is not much of a problem as I see it.

<<<-- Actually, switches are probably not the correct way to do it. With the low power consumption, a better way may be to simply use a mechanical cover over the sections I want dark.-->>>

A cover sounds fine to me. But a switch might be more practical. In fact we could use both.

Agreed

<<<-- I am interested in controlling the glare that is always a possiblity with a ring light.-->>>

There might be some lateral glare, but the LEDs are quite directional at about 20 degrees.

And if the light hits a reflective object head-on, it will reflect right back to the lens as glare.


Carlos -->>>