plans for SIT modules

[speleogen]

Does anyone know where I can source parts and plans for LED SIT modules? I'd like to give cave photography a try and they seem to be the way to go.

Thanks,
John

[NZcaver]

I'm not sure what a 'SIT module' is, but I know where you can get LEDs and drivers for home built projects at a reasonable price.

Try http://www.dealextreme.com/ and search for whatever you need.

[MUD]

You need to contact Nathan "Realms" Williams of the Huntsville Grotto. He's the original developer of the S.I.T. modules for cave photography. Sustained Illumination Technique using small led modules instead of flashes. Open the shutter for a few seconds and it makes for some mighty fine lighting! Nathan actually had an article on SIT photography in the May 2007 NSS News. Pretty much explains it all right there. There are others on this forum who build and use them too. I'm sure they'll see this post and chime in.... I'd like to have several myself!

[NZcaver]

Sustained Illumination Technique using small led modules instead of flashes. Open the shutter for a few seconds and it makes for some mighty fine lighting! Nathan actually had an article on SIT photography in the May 2007 NSS News. Pretty much explains it all right there.

Oh right, that rings a bell. Reminds me I still have to get around to patenting my own PIT method. You know - Pulse Illumination Technology (aka electronic flashguns).

Using a fixed light source like LEDs for illuminating cave time exposures is not exactly something new.

[MoonshineR DavE]

Cavemud is right, Nathan Williams is the one to contact. He goes by Realms here on the forum. I believe he has moved from using LEDs and is using CF bulbs now. Don't hold me to that though.

[speleogen]

Thanks all for the info. I sent Nathan an email through his Realms of Reality website, but haven't heard from him yet. Most of his stuff seems to be on Fickr now. And I did see some mention there of CF bulbs. I work in the semiconductor industry though and I'm just naturally drawn to LEDs

Now I have to choose a camera. I haven't owned one since my old Olympus OM-1 and I think things have changed a bit . . .

John

[Footleg]

I gave a talk on this at the convention in Texas last Summer. And again at a recent UK based caving technology meeting. You can download the (16MB) powerpoint presentation from the UK event from here:
http://bcra.org.uk/proc/cts10/Footleg%2 ... graphy.ppt

It is mainly pictures to illustrate the talk, but you can see the internals of the LED photography lights I have made. The LEDs came from DealExtreme.com ( http://www.dealextreme.com/details.dx/sku.12721 ) and the drivers were from Kaidomain.com ( http://kaidomain.com/ProductDetails.aspx?ProductId=6386 )

The main problem with building lights using these LEDs is the huge amount of heat given off. If you do not draw this heat away from the LED then it will not last very long at all. So the take home lesson is to use a metal housing and provide a good heat path from the LED to the housing. The talk also includes some pictures of twin P7 LED lights made using the same LEDs and drivers by UK caver Rob Eavis.

I have also used MagicShine mountain biking lights which use the same LED. Search for them on Google, or on the DealExtreme or Kaidomain websites.

[speleogen]

Thanks for the info!

[Footleg]

I have recently learned of the CREE XM-L which looks like a much more efficient new LED of comparable brightness and power requirements as the P7 LEDs I used. Can be driven at variable currents up the 3A, and is more efficient at less than full power. Cheaper too, so a couple could be run at half power for the same cost as a P7 LED and significantly more efficient. I'm going to try to prototype some new SIT lights using them.

You might also be interested to know that a UK caver is now selling SIT modules based on the CREE XPG LED.
http://www.bisun.co.uk/pharos.html

The Bisun SIT module comes with flood and spot modes in one unit.

[innermostphoto]

Over the last month we have been experimenting with our new color balanced HAL lights. HAL stands for Hal's Auxiliary Lighting. It has been my experience the LED's have severe limitations when it comes to making a QUALITY photo. The plus side to them is they are easy to use, creates a nice blur effect on moving water, and they act as modeling light before the shot. The negative is as I said before quality is sometimes sacrificed to gain enough light and the model must be extremely still in order to prevent ghosting. Additionally, Nathan's photos (nice as they are) are shopped but of course mine are too however, not to the extent Nathan's are. The jury's decision on LED's is still out for me right now. The pictures I have done thus far could have been achieved without the use of external flashes but that is not the point now is it? The point is it can be done.

I don't have any on my web site as yet but you can see some on my facebook page for Bob Biddix. Just send me a friend request.

bob biddix
Innermost Imagery
http://www.innermostimagery.com

[LukeM]

Bob, are you talking about using corrective color gels when you say "color balanced"?

Short of that, I think what is needed to get near the excellent color rendition of a strobe or flashbulb is a high CRI (color rendering index) LED. Unfortunately high CRI versions of the latest LED's lag way behind in production and really high CRI LEDs (approaching incandescent levels) are quite rare. Further, they tend to take a serious hit in the efficiency department to gain the better color rendering. The next best bet seems to be "neutral" color temp LED's that aren't necessarily high CRI. Like you said, Photoshop is usually heavily employed to correct the color balance of LED-lit photos.

I think we're getting to the point where very soon it will be possible to light small areas with pretty fast shutter speeds using "SIT modules".

[innermostphoto]

No, color gels are not used.

bob biddix
Innermost Imagery
http://www.innermostimagery.com

[LukeM]

No, color gels are not used.

Care to elaborate on what are you using for these auxiliary lights? I'm always interested in new techniques.

[Hal]

The modules use Seoul SSC P4 high CRI leds. They are 5000K color temp and CRI=93. I do not know of any sources for these now. The best leds out there right now for photography would be the Nichia 119, but obtaining them is difficult.

Hal

[LukeM]

Thanks for the info Hal. Sounds like you found the right LED's for the job. Any examples of the results yet, or still too early for that?