LED Lights

Any electronic experts in the house?

Can you shed any light on these LED lights? Might be worth it for close up/macro work.
http://cgi.ebay.co.uk/Pentax-Nikon-Kodak-Sony-Olympus-PHOTO-SHOOT-4-x-LIGHTS_W0QQitemZ7594020795QQcategoryZ3860QQrdZ1QQcmdZViewItem

Uh huh.
There are several different types of white LED. They vary in wavelength, as well as brightness and angle of illumination. I think it's Kingbright, one of the largest LED manufacturers, that make some nice ones that are pretty white (not so blue), and with a good angle.

The only trouble with white LEDs is their forward voltage. Regular LEDs are about 1.2V, but the whites are around 4.2V. Makes it a real pain for powering actually. I can't remember their current off hand, but it's a lot higher than regular 3mm or 5mm red LEDs, and a PP3 isn't going to last long at all.

Ideally you need a couple of NiMH AA cells and a step-up switch mode supply to get to the 4.2V. It's one of those projects I've always meant to get round to, and have the LEDs, but not the time

Let me know if you want more info

Matt

Hi,

I would be VERY wary of any LED lights. Just recently our low voltage bulb in a reading lamp went and I tried an LED replacement as the power consumption was so much lower...the bulb cost about £7 pounds and was absolutely rubbish. It was hardly any brighter than a candle...hence the low power consumption. It went right back to Focus diy.

Cheers Steve.

I got this superb flashlight which uses LED's as a lightsource.
It uses 17 bright LED's which together give an awfull lot of light.

LED lighting will used much, much more in the coming years. Just look at cars and how many manufacturers use LED's for the rear light clusters.

pure white light is still 'difficult' with LED's but the development is still ongoing. For use in flashlights I do not want anything else then LED's, only for certain applications (light which has to create a focused beam) flashlights will be needed.

LEDs have moved along quite a bit. I use torches with LEDs and they are excellent.

In Dentistry, LEDs are used in light curing units, which set the white coloured filling materials. Some single LED lights can deliver over 1400 mW per square cm of energy. This is quite a considerable output, and with a life expectancy of 100,000 hours makes them the units of choice.

Of course we are talking about fairly small areas of illumunation, but if you want more light you just put in more LEDs!

We are going to see a lot more of LED lighting in the future, especially as they get this small http://www.luxeonstar.com. I always have an LED headtorch in my rucksack, but I use a hybrid LED/Xenon bulb version for serious night walking, as the range of LED's is limited unless combined with clever (and bulky) reflectors and lenses, as seen in some cars. Watch this space (but you might need to wear shades)

I too use an LED torch, very good for what it is intended for. ie giving some light for my very forgiving human eyes.

Hence the main problem, the human eye can compensate for many different light levels and many different colours.

Unfortunatley our cameras have not had millions of years of evolution so they like specific colours (or like to be told what colours to expect)

It would be brilliant if you could switch the camera on and give it a few seconds to aclimatise and compensate for the light and then take perfect pictures.

re- the original post and use for macro work.

I have used a 'white' LED torch to illuminate an object from oneside, a tungsten bulb in an angle-poise lamp on the other. With camera WB set to Tungsten, you get great colours - still a yellow-orange from the tungsten, plus a blue from the LED torch
Andy

Pentax *ist DS and I presume D & DL too, can set any white balance manually to any colour of light. Page 113, 114 of your manual shows you how.

Chris

precisely, just point it at a white piece of paper, doesn't need to be in focus.
Works beautifully.
Better still, take these shots in raw mode so you can adjust everything to your liking.

Thanks for the info folks, maybe buy a couple of LED torches to mess around with first.

Hi all....LED's again.

I have actually got round to building a prototype LED lighting rig for macro stuff.

While I was browsing around one of our local independent hardware stores I came across a display of 230Vac LED reflector type bulbs (no wattage or angle info) but they were only £3.99 each, they had white, blue, yellow, red and green ones on display but.......they had a GU10 fitting that I was not familiar with so I passed on bye.

A couple of days later I was in B&Q and spied this....perfect, just what I was looking for


240Vac with GU10 fittings in small moulded plastic lamp holders fitted with gambles.....

Here it is out of the box.....



Prior to this I had already bought 4x 18" goosenecks off ebay for £2.00 each in anticipation of the forthcoming project, went back to the hardware store and bought a couple of the white LED's that I had seen.

So Sunday afternoon I commandeered the kitchen worktops (after I had cooked and served dinner, got to keep in the good books) and set about creating McBrian's Macro Rig® (£34.99 available soon from all good photographic stores).
After lots of fiddly disassembly, soldering (swearing) and reassembly I came up with this..........






I’ve not had a lot of time to try it out but it looks like the *istD copes with the white balance OK on auto, will post some more pics when I get the full compliment of 4 bulbs, the great thing about this rig is the bulbs are nice and cool, no problem sticking on diffusers, paper snoots........with selotape or bluetack.
Full assembly instruction available on request.

Well that probably deserves a genuine Blue Peter badge!

Typical, kettle never far away

I like it Brian. The light certainly has a blue hue to it. Does that balance out OK and still render the colours properly?.

It is possible to get near white LED's having about 1 watt output. I have a torch with one in and it really is very bright.

Is there enough room for a small to medium sized light tent in the middle ?

I'm experimenting making a flash macro system at the moment. I've got most of the bits, I just need to fabricate a couple of arms to mount the guns on. I know I could buy a flash rig but they are astronomically expensive. I've spent about £50.00 so far, the rest is labour.

Keep at it.

I admire your inginuity. Good workmanship (may I suggest using a sheet of plexi instead of particle board?). Imagine the fun one could have with a cokin filterholder mounted to each light.
I've found using metal dryer ducting and my studio lights works A OK in studio for me, and have been using flashlight for focus assist when using ring light for macro.
I am considering using small battery powered florescent lamps or video lights for location/low light work.