One Million Lumen

[peterk]

2011 but may provide useful information about LED's for photography
". This article presents a solution for flash illumination with high power white LED controlled by a single chip boost converter. Furthermore, the setup of a suitable application for a cell phone, smart phone or PDA with small form factor and optimized battery loading are presented"
http://focus.ti.com/download/trng/docs/seminar/Topic%2011%20-%20White%20LED%20Flashlight.pdf

 

[Antwan]

Duncan, I wish my camera would produce the same results as your at anything higher than iso800!

This was taken with a single lamp (100lumens ish) 3m to the left of the camera over 4 seconds on my old bridge camera, all depends on what your going for really doesn't it.
Giants Hole by Anthony aka Antwan, on Flickr

Now what I can do with my flash guns is set one or more to strobe, Trouble is I dont get to go caving very often so all the creative uses I have in my head don't come out to play very often, but I could for example set up a 1/2 power flash as a main scene light then have a 1/64 fast strobe back lighting a waterfall or a selective part of the scene for 1/30th or longer so in theory you can freeze the 'action' without freezing the water.

I need to get out and practice like you!

Pete, Interesting article, Thanks

 

[bograt]

Nice picture Antwan, 'Eating House in Spate?' could maybe benefit from a bit of spread lighting from somewhere above the 'models' head??

Or even if he/she had their headlight on pointing upwards?

 

[blackholesun]

As mentioned by rom82, there is a serious problem with using LEDs for photography - the colour.

A (metz 45) flashgun gives out
http://medicalphotography.com.au/Article_03/IRFig11.gif

Whereas a typical high power LED spectrum is
http://i.stack.imgur.com/uJqtZ.png

LEDs really lack in certain areas of the spectrum, and you can't just shift the white balance for this. If an object is equally reflective at 450nm and 490nm, it'll look almost the same as if it is just reflecting the 450nm light as there's so little 490nm hitting the object. This leads to the colours looking a bit rubbish. Often they also look washed out.

This is all compounded by the fact that LEDs usually require high ISOs and thus the colours will be suffering anyway.

This is far from the best example out there, but shows the colours that come naturally with flash, even with a cheap camera
https://www.flickr.com/photos/127423544@N02/15118458876/in/album-72157647180289046/lightbox/
The rock shows actual colour throughout the image instead of the grey/cold blue common from LEDs. The orange on the helmet stays controlled, but more importantly the red oversuit is neither blown out and saturated nor is it washed out and weak in colour.

I'm not claiming this or any of the others to be images of note, and I think it's very possible to get stunning images from LEDs. I just think its really worth being aware of how they could make it difficult to get the colours you want.

I usually find smooth water in action shots slightly odd as there is an inherent contradiction - is the person posing or not? I stick with flash as ever for things like:
https://www.flickr.com/photos/127423544@N02/15526087280/
and
https://www.flickr.com/photos/127423544@N02/15465822219/

I do like the 1/30 shot though; I think this shows how you can achieve the tricky task of action and flowing water together. Much slower or faster would case the contradiction to arise in my head again. Multisecond shots of water can also be beautiful, but completely remove the chance of any action

Anyway, I'm rambling. My point: I think the majority of cavers would be better served with a handful of dirt cheap second hand flashguns and triggers than any LED source, flash or floodlamp.

 

[Duncan S]

Hmm - that's an interesting point about colours being washed out.
Looking back at my shots it is very possible I can see the effect.
Sometime soon I'll try a same shot with LED and Flash from the same position and see what differences we get.

 

[Roger W]

Interesting, about colours being washed out on film with LED lights.  How far does this affect what we see with the naked eye?

From candles and carbide through old-fashioned Oldhams to xenon bulbs and LEDs - which is best to see the cave as it "really" is?

Sorry if I'm going off topic.

 

[blackholesun]

Roger has reminded me of a caveat that I should have added:

If you use flash guns for photos, but LEDs for lighting, then the colours won't match the ones that you saw. LEDs reflect much better what the cave looked like to a caver at the time of the photo.

This can make you feel like your images are dishonestly warm, or somehow misleadingly saturated, like you've just taken a bog standard sunset and jacked up the colours to make it something extraordinary.

 

[Olaf]

Well, if you take a green lamp underground, the cave "really" is green. If our sun was blue rather than sunlight coloured, everything around us would "really" be blue. I think it's not a question of how well a photo captures reality (because ideally they would then be as pitch black as a cave), but what sort of colours you as an artist like to have in your photos. And for my personal taste the previously linked photo of a red caver on the orange rope in a redish cave is a bit too much on the red side. Maybe that's because I've always caved with LEDs and I'm much more used to the blueish LED appearance of caves.

On a more general note, the problem blackholesun mentioned is described on wikipedia at http://en.wikipedia.org/wiki/Color_rendering_index and reading through it, I get the impression that trial and error is currently still the state-of-the-art in determining which light source to use for with camera.

 

[Fulk]

I've noticed that the walls of caves (I'm talking of bare rock now, not muddy rock) appear brownish in digital photos taken by electronic flash, while they (normally) appear grey by LED light.

 

[kdxn]

It would be interesting to compare photographs taken with different warmth LED's, Carbide and Oldham Lead Acid Lamps.

For example, the latest Cree XHP70 (4022lumen at 32W) warm white has a more realistic daylight spectra.
The Cool White version features a significant blue spike.
http://www.cree.com/LED-Components-and-Modules/Products/XLamp/Arrays-Directional/XLamp-XHP70

Kyocera report an LED research development which corresponds much better to the daylight spectrum.
http://www.kyocera.eu/index/news/previous_news/news_archive_detail.L2NvcnBvcmF0ZS9uZXdzLzIwMTQvS1lPQ0VSQV9ERVZFTE9QU19MRURTX1dJVEhfRVhDRUxMRU5UX1JFTkRFUklOR19PRl9USEVfREFZTElHSFRfU1BFQ1RSVU0~.html

Given that caves are not naturally lit.
What should a cave look like ?
The eye of the beholder..........
.........or based upon the predominant light source ?

 

[kdxn]

A further suggestion, try the Xicato XTM LED. Especially the 'Artist' spec version. These are typically used in Art Galleries as they provide the most realistic daylight spectra.